Sex-based forearm morphology in climbers: an ultrasound study and it´s predictive value for climbing style

Sex-based forearm morphology in climbers: an ultrasound study and it´s predictive value for climbing style | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Sex-based forearm morphology in climbers: an ultrasound study and it´s predictive value for climbing style Harryson Caro-Bethancur, María Bravo-Aguilar, María Estrella-Riquelme, and 7 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7530539/v1 This work is licensed under a CC BY 4.0 License Status: Under Revision Version 1 posted 12 You are reading this latest preprint version Abstract Background : Sport climbing is a physically demanding discipline that places repetitive mechanical load on the upper limbs, potentially leading to morphological adaptations or overuse injuries. Despite this, musculoskeletal ultrasound (USI) has been underutilized in climbing research. This study aims to investigate sex-related differences in forearm muscle and nerve morphology in climbers and to determine whether these structural features can predict climbing specialization (bouldering vs. sport climbing). Methods : A cross-sectional study was conducted with 50 recreational climbers (25 males, 25 females). Ultrasound imaging was used to assess the thickness of key forearm muscles (brachioradialis, pronator teres, flexor digitorum superficialis/profundus, pronator quadratus) and the median and radial nerves. Results: Significant sex differences were observed for all muscles and the median nerve (p < 0.001), with males exhibiting greater thickness. No differences were found for the radial nerve or between dominant and non-dominant limbs. Logistic regression identified flexor digitorum profundus (FDP) thickness as the strongest anatomical predictor of sport climbing, with each 1 mm increase in FDP thickness raising the odds of being a sport climber by 48.2%. The final model, including FDP, median nerve, and pronator teres thickness, showed excellent discriminative ability (AUC = 0.814, accuracy = 82%). Conclusions: Ultrasound-based assessments revealed robust sex-related morphological differences in climbers’ forearm musculature and median nerve. Greater FDP thickness is strongly associated with sport climbing specialization. These findings suggest that USI may be a valuable tool for profiling climbers, guiding training programs, and informing injury prevention strategies. Health sciences/Anatomy Health sciences/Health care Figures Figure 1 Figure 2 Figure 3 Introduction Sport climbing, practiced in both indoor and outdoor settings, involves the repetitive execution of static and dynamic movements that require muscular strength, balance, and postural control. This discipline has experienced a significant increase in popularity, culminating in its inclusion as an official Olympic sport at the Tokyo 2020 Games ( 1 ). In Spain, according to the Spanish Federation of Mountain and Climbing Sports (FEDME), sport climbing rack as the fifth most practiced sport, with over 290,000 registered federated athletes and an extensive network of specialized climbing facilities. Sport climbing includes three primary modalities, speed climbing, lead climbing, and bouldering. Regardless of the discipline, climbing involves repetitive static and dynamic movements that demand significant muscular strength, postural control, and neuromuscular coordination, particularly of the upper limbs ( 2 ). These biomechanical requirements, combined with the inclined surfaces and frequent suspension of the climber's body weight from the upper extremities, lead to substantial loading of the forearm, hand, and fingers ( 3 , 4 ). While grading systems vary across countries and disciplines, the International Rock Climbing Research Association (IRCRA) has proposed a standardized classification system based on performance level: novice, intermediate, advanced, elite, and high elite ( 5 ). In this study, climbing ability was categorized using the French scale grading system, which applies a combination of numbers and letters in both lead climbing and bouldering to represent route difficulty ( 6 ). Due to the biomechanical demands of sport climbing such as sustained gripping on inclined surfaces and prolonged suspension of body weight using the upper limbs here is a significant mechanical load placed on the musculoskeletal structures of the upper extremity. This sustained load has been associated with a high prevalence of overuse injuries in climbers. A systematic review by Quarmby et al. reported that up to 93% of climbing-related injuries are classified as overuse injuries, with the fingers being the most frequently affected anatomical region ( 7 ). Similarly, a descriptive study conducted by McDonald et al. found that 39.4% of injuries occurred in the fingers, followed by 17.7% in the shoulders and 15.6% in the elbows, with tendinous strains, muscle strains, and tendinopathies being the most commonly reported diagnoses, accounting for 45.8% of all cases ( 8 ). One of the most commonly used grip techniques in climbing, particularly on small holds, is the crimp grip, in which the proximal interphalangeal joint is flexed to approximately 90 degrees and the distal interphalangeal joint remains in hyperextension. This grip configuration has been associated with increased mechanical stress on the flexor tendon complex, especially the flexor digitorum superficialis and flexor digitorum profundus muscles, which play a key role in sustaining body weight during climbing tasks ( 9 ). Climbing performance has been the subject of numerous studies that have examined both physical and psychological attributes, including strength, endurance, flexibility, and mental resilience. Among the physical assessments, grip strength and muscular endurance tests have demonstrated strong validity and reliability in evaluating climbing-specific capabilities ( 6 , 10 , 11 ). These measurements are particularly relevant given the repetitive and high-load nature of gripping during training and competition. Despite the growing interest in functional and morphological adaptations in climbers, musculoskeletal ultrasound has not yet been widely employed as an analytical tool in climbing research. Currently, there are no published studies that use ultrasound imaging to explore associations between anatomical structures and sport-specific factors, such as climbing discipline, performance level, training history, or injury occurrence in the upper limbs ( 12 ). The forearm region plays a fundamental role in climbing biomechanics, as it houses the primary muscle-tendon units responsible for generating and sustaining grip force ( 13 ). Given the cumulative loading experienced during prolonged climbing sessions, this segment is considered particularly vulnerable to overuse injuries and may present detectable morphological adaptations related to training exposure and athletic profile. In this context, musculoskeletal ultrasound may provide valuable information regarding anatomical changes induced by sport-specific demands and potential risk factors associated with overuse injuries in this population. Furthermore, this tool enables the detailed description of structural findings in climbers and the exploration of possible correlations with demographic variables, such as sex, age, and climbing discipline, contributing to the development of targeted preventive and clinical strategies. Methods Study design This observational cross-sectional study was carried out between December 2024 and February 2025, in accordance with the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines ( 14 ). Participants A total of 50 recreational rock climbers were included in this study (Table 1 ). The sample was divided into two groups according to sex: male (n = 25) and female (n = 25) participants. Inclusion criteria comprised male and female climbers aged between 18 and 60 years, with regular climbing practice for at least the previous three months. Exclusion criteria included any upper limb musculoskeletal injury occurring within the last three months, and history of surgery within the past six months. Table 1 Participant Characteristics Variable Mean ± SD or n (%) Age (years) 37.68 ± 8.52 Height (m) 1.71 ± 0.09 Weight (kg) 65.14 ± 11.85 BMI (kg/m²) 22.29 ± 3.09 Years of Experience 3.52 ± 3.05 Sex Male 33 (66%) Female 17 (34%) Training Volume 1-1.5 h/week 2 (4%) 2-2.5 h/week 10 (20%) 3-3.5 h/week 9 (18%) 4–5 h/week 8 (16%) > 5 h/week 11 (22%) External Activity Yes 38 (76%) No 12 (24%) Climbing Type Boulder 33 (66%) Sport Climbing 17 (34%) Climbing Grade Boulder 5 4 (8%) 6 16 (32%) 7 11 (22%) 8 2 (4%) Climbing Grade Sport 5 5 (10%) 6 8 (16%) 7 4 (8%) Previous Upper Limb Injury Yes 20 (40%) No 30 (60%) Table 2 MANOVA: Muscle and Nerve Measurements by Sex and Dominant Side. Variable Dominant Non-Dominant Sex (F, p-value) Dominant Side (F, p-value) Sex ✻ Dominant Side (F, p-value) Male Female Male Female Brachioradialis 18.31 ± 2.56 12.36 ± 1.82 18.27 ± 2.83 12.23 ± 1.71 137.079, < 0.001 0.020, 0.887 0.008, 0.930 Pronator Teres 11.69 ± 1.85 9.33 ± 1.59 11.08 ± 1.65 9.09 ± 1.38 37.985, < 0.001 2.098, 0.151 0.280, 0.598 Flexor Digitorum Superficialis 13.23 ± 2.55 10.07 ± 1.41 12.75 ± 1.81 9.40 ± 1.52 59.675, < 0.001 1.870, 0.175 0.049, 0.826 Flexor Digitorum Profundus 15.21 ± 2.28 11.67 ± 1.89 15.46 ± 2.35 10.97 ± 1.72 77.502, < 0.001 0.033, 0.857 1.090, 0.299 Pronator Quadratus 13.67 ± 1.63 10.12 ± 1.53 13.44 ± 1.84 9.68 ± 1.08 115.368, < 0.001 0.867, 0.354 0.092, 0.762 Radial Nerve 8.59 ± 1.32 8.15 ± 1.08 8.86 ± 1.54 8.98 ± 1.41 0.317, 0.575 2.786, 0.098 0.920, 0.340 Median Nerve 10.69 ± 1.28 9.99 ± 0.80 10.16 ± 2.20 9.03 ± 1.02 7.752, 0.006 4.718, 0.032 0.439, 0.509 Notes: Muscle and nerve measurements are in millimeters (mm). Statistical significance set at p < 0.05 (bold). Sample size calculation The sample size was calculated using G*Power 3.1.9.2 software, based on preliminary data from a pilot study (n = 20) assessing the thickness of the flexor digitorum profundus muscle (mm). The pilot included two independent groups of climbers: 10 males (mean ± SD: 6.2 ± 1.4 mm) and 10 females (5.1 ± 1.3 mm). A two-tailed hypothesis was applied, with an effect size (Cohen’s d ) of 0.83, an alpha level of 0.05, statistical power (1–β) of 0.80, and an allocation ratio of 1. Based on these parameters, the minimum required sample size was determined to be 50 participants, with 25 in each group. Ethical considerations This study received ethical approval from the Ethics Committee of the European University. All participants provided written informed consent prior to their inclusion in the research. The procedures followed were in accordance with the ethical principles outlined in the Declaration of Helsinki for research involving human subjects. Data Availability The datasets generated and/or analysed during the current study are not publicly available due to privacy and ethical restrictions but are available from the corresponding author on reasonable request. Data Collection Instruments and Ultrasonography Procedure: A digital questionnaire was administered to collect detailed information on participants’ anthropometric characteristics, history of upper limb injuries, and physical activity related or unrelated to climbing. Participant confidentiality was ensured throughout the study. Ultrasound measurements were recorded in a custom-designed database developed by the research team. A SonoScape E2 ultrasound system (SonoScape, Madrid, Spain), conductive gel, a portable examination table, and disposable paper were used during the assessment process. All participants were evaluated in a seated position, with the elbow flexed to approximately 120°, ensuring consistency in posture throughout data collection. For the assessment of muscular structures, the brachioradialis muscle was evaluated with the forearm in pronation and supported on the examination table. The transducer was placed transversely over the supracondylar region, and muscle thickness was measured where the muscle belly ran parallel to the bone surface. To examine the pronator teres, the forearm was positioned in supination. The transducer was first placed over the brachioradialis and then rotated and shifted medially and distally along the forearm (Fig. 1 A). Activation was confirmed by asking the participant to pronate the forearm ( 15 ). The flexor digitorum superficialis and flexor digitorum profundus muscles were also examined with the forearm in supination. The transducer was positioned along the middle third of the forearm, and correct identification of each muscle was verified by requesting metacarpophalangeal joint flexion for the superficial flexor (Fig. 1 B) and distal phalanx flexion for the deep flexor ( 16 ). The pronator quadratus was assessed by placing the probe transversely at the midpoint between the radius and ulna in the same supine position, and vertical muscle thickness was measured (Fig. 1 C). Regarding the peripheral nerves, the median nerve was evaluated with the forearm in supination and the shoulder slightly externally rotated. The nerve was identified on the medial aspect of the proximal third of the forearm, near the elbow joint (Fig. 1 B). The radial nerve was located by sliding the transducer slightly distally, identifying it between the brachioradialis and pronator teres muscles, and its cross-sectional area was recorded (Fig. 1 D) ( 17 ). Statistical Analysis The statistical analyses for this study were conducted using JASP (Version 0.17.3) and SPSS (Version 29, IBM Corp., Armonk, NY, USA) for Windows. The analyses included descriptive statistics, normality tests, independent samples t-tests, Mann-Whitney U tests, multivariate analysis of variance (MANOVA), and hierarchical logistic regression, following the STROBE guidelines for observational studies. Descriptive statistics were calculated for continuous variables. These variables were summarized as means and standard deviations (SD) for normally distributed data, and as medians and interquartile ranges (IQR) for non-normally distributed data. Proportions were reported for categorical variables. To assess normality, the Shapiro-Wilk test was used, with a significance threshold set at p < 0.05, indicating a deviation from the normal distribution. Homogeneity of variances was evaluated using Levene's test, with p < 0.05 suggesting unequal variances. Independent samples t-tests were conducted to compare means between male and female climbers for normally distributed variables. Effect sizes were calculated using Cohen's d, with values below 0.2 indicating a small effect, 0.2 to 0.5 a medium effect, and above 0.8 a large effect. For non-normally distributed data, Mann-Whitney U tests were employed, with effect sizes reported as rank biserial correlations. A MANOVA was conducted to examine the main effects of sex, dominant side, and their interaction on muscle and nerve thickness. The analysis used Pillai’s Trace as the multivariate test statistic. Pillai’s Trace values closer to 1 indicate stronger multivariate effects. Univariate ANOVAs were then conducted for each muscle and nerve to identify significant differences within the MANOVA model. Post-hoc pairwise comparisons were realized for significant main effects, using 95% confidence intervals (CI) to estimate the precision of the observed differences. Bonferroni correction was applied to adjust for multiple comparisons, maintaining a family-wise error rate of 0.05. Hierarchical logistic regression models were developed to identify anatomical and morphological predictors of climbing style (sport climbing vs. bouldering). Predictors were entered in a stepwise manner, with model fit assessed using the likelihood ratio (Δχ²) test at each step. Model performance was evaluated using McFadden's R², Nagelkerke's R², Tjur's R², and the area under the receiver operating characteristic (ROC) curve (AUC). Multicollinearity was assessed using variance inflation factors (VIF), with a threshold of 5 indicating potential multicollinearity. Residual diagnostics included the Durbin-Watson test to assess autocorrelation. Assumptions for each analysis were checked, including normality, homogeneity of variance, multicollinearity, and independence of residuals. Any violations were addressed accordingly to ensure the robustness of the results. Results The baseline characteristics of the 50 climbers included in the study are presented in Table 1 . No significant differences were observed in age between males (37.24 ± 9.05 years) and females (38.53 ± 7.45 years) (t(98) = -0.714, p = 0.477, d = -0.151). In contrast, significant differences were found for height, weight, and BMI. Males had significantly greater height (1.74 ± 0.07 m) than females (1.63 ± 0.07 m), (t(98) = 8.092, p < 0.001, d = 1.708). Similarly, males exhibited higher weight (70.12 ± 10.69 kg) compared to females (55.47 ± 7.09 kg) (t(98) = 7.205, p < 0.001, d = 1.521). Regarding BMI, males (23.04 ± 3.30 kg/m²) presented significantly higher values than females (20.82 ± 1.95 kg/m²) (t(98) = 3.606, p < 0.001, d = 0.761). MANOVA effects The MANOVA revealed a significant main effect of sex (Pillai’s Trace = 0.689, F(7, 90) = 28.437, p < 0.001), while the main effect of dominant side (Pillai’s Trace = 0.098, F(7, 90) = 1.394, p = 0.218) and the interaction between sex and dominant side (Pillai’s Trace = 0.033, F(7, 90) = 0.443, p = 0.872) were not statistically significant, indicating that the differences were primarily driven by sex rather than limb dominance or the interaction between these factors. Sex Muscle thickness differences were significant for the Brachioradialis (F = 137.079, p < 0.001), Pronator Teres (F = 37.985, p < 0.001), Flexor Digitorum Superficialis (F = 59.675, p < 0.001), Flexor Digitorum Profundus (F = 77.502, p < 0.001), Pronator Quadratus (F = 115.368, p < 0.001), and Median Nerve (F = 7.752, p = 0.006). In contrast, the Radial Nerve did not show a significant sex difference (F = 0.317, p = 0.575). Dominant Side The main effect for dominant side was not statistically significant for any of the muscles or nerves assessed. The Brachioradialis (F = 0.020, p = 0.887), Pronator Teres (F = 2.098, p = 0.151), Flexor Digitorum Superficialis (F = 1.870, p = 0.175), Flexor Digitorum Profundus (F = 0.033, p = 0.857), Pronator Quadratus (F = 0.867, p = 0.354), Radial Nerve (F = 2.786, p = 0.098), and Median Nerve (F = 4.718, p = 0.032) did not show significant differences based on the dominant side. Interaction of Sex and Dominant Side Similarly, the interaction between sex and dominant side was not statistically significant for any of the muscles or nerves measured. The Brachioradialis (F = 0.008, p = 0.930), Pronator Teres (F = 0.280, p = 0.598), Flexor Digitorum Superficialis (F = 0.049, p = 0.826), Flexor Digitorum Profundus (F = 1.090, p = 0.299), Pronator Quadratus (F = 0.092, p = 0.762), Radial Nerve (F = 0.920, p = 0.340), and Median Nerve (F = 0.439, p = 0.509) all showed no significant interaction effects. (Fig. 1 ). Post-Hoc Analysis Post-hoc comparisons revealed that the Brachioradialis in males was significantly thicker than in females for both the dominant (MD = 5.95 mm, 95% CI [4.86, 7.04]) and non-dominant sides (MD = 6.04 mm, 95% CI [4.87, 7.21]). Similarly, the Pronator Teres in males was significantly thicker than in females for both the dominant (MD = 2.36 mm, 95% CI [1.50, 3.22]) and non-dominant sides (MD = 1.99 mm, 95% CI [1.17, 2.81]). For the Flexor Digitorum Superficialis, males also had greater thickness on both the dominant (MD = 3.16 mm, 95% CI [2.15, 4.16]) and non-dominant sides (MD = 3.35 mm, 95% CI [2.34, 4.36]). The Flexor Digitorum Profundus showed a similar pattern, with significant differences for both dominant (MD = 3.54 mm, 95% CI [2.41, 4.67]) and non-dominant sides (MD = 4.49 mm, 95% CI [3.30, 5.68]). The Pronator Quadratus also demonstrated significant sex differences for both dominant (MD = 3.55 mm, 95% CI [2.67, 4.43]) and non-dominant sides (MD = 3.76 mm, 95% CI [2.90, 4.62]). Finally, the Median Nerve was significantly thicker in males for the dominant (MD = 0.70 mm, 95% CI [0.20, 1.20]) and non-dominant sides (MD = 1.13 mm, 95% CI [0.44, 1.82]). In contrast, no significant differences were observed for the Radial Nerve on either the dominant (MD = 0.44 mm, 95% CI [-0.15, 1.03]) or non-dominant side (MD = -0.12 mm, 95% CI [-0.70, 0.46]). Logistic Regression A hierarchical logistic regression analysis was conducted to identify the anatomical and morphological predictors of sport climbing style compared to bouldering tstyle In the initial model (M₁), only the thickness of the flexor digitorum profundus (FDP) was included as a predictor. This variable significantly improved model fit (Δχ²( 1 ) = 21.709, p < 0.001) and accounted for 27.0% of the variance (Nagelkerke R² = 0.270). The FDP thickness was a significant positive predictor (B = 0.394, SE = 0.096, OR = 1.482, 95% CI [1.231, 1.784], p < 0.001), indicating that for each 1 mm increase in FDP thickness, the odds of being a sport climber increased by approximately 48.2% (Table 3 and Table 4 ). Table 3 Logistic Regression Model Summary for Predicting Climbing type Model Deviance AIC BIC df ΔΧ² p McFadden R² Nagelkerke R² Tjur R² Cox & Snell R² M₀ 128.207 130.207 132.812 99 0.000 0.000 M₁ 106.498 110.498 115.708 98 21.709 < .001 0.169 0.270 0.210 0.195 M₂ 103.314 109.314 117.129 97 3.184 0.074 0.194 0.305 0.242 0.220 M₃ 99.167 107.167 117.588 96 4.147 0.042 0.227 0.349 0.289 0.252 Table 4 Logistic Regression Models for Predicting Climbing Type Based on Muscle and Nerve Thickness. Wald Test Model Parameter Estimate Standard Error Odds Ratio z Wald Statistic df p M₀ (Intercept) -0.663 0.211 0.515 -3.142 9.873 1 0.002 M₁ (Intercept) -6.337 1.443 0.002 -4.392 19.287 1 < .001 Flexor Digitorum Profundus 0.394 0.096 1.482 4.080 16.650 1 < .001 M₂ (Intercept) -8.426 2.000 2.192×10 − 4 -4.212 17.741 1 < .001 Flexor Digitorum Profundus 0.330 0.100 1.391 3.289 10.820 1 0.001 Median Nerve 0.295 0.182 1.343 1.617 2.616 1 0.106 M₃ (Intercept) -7.420 2.152 5.990×10 − 4 -3.448 11.888 1 < .001 Flexor Digitorum Profundus 0.402 0.113 1.495 3.554 12.628 1 < .001 Median Nerve 0.418 0.217 1.519 1.927 3.712 1 0.054 Pronator Teres -0.305 0.158 0.737 -1.927 3.714 1 0.054 Model 2 (M₂) introduced the median nerve (MN) thickness as an additional predictor. This addition further improved the model fit (Δχ²( 1 ) = 3.184, p = 0.074), resulting in a Nagelkerke R² of 0.305, explaining 30.5% of the variance. In this step, FDP thickness remained a significant positive predictor (B = 0.330, SE = 0.100, OR = 1.391, 95% CI [1.136, 1.703], p = 0.001), while the median nerve thickness approached significance (B = 0.295, SE = 0.182, OR = 1.343, 95% CI [0.938, 1.922], p = 0.106) (Table 3 and Table 4 ). In the final model (M₃), the pronator teres thickness was included as a third predictor. This model significantly enhanced the overall fit (Δχ²( 1 ) = 4.147, p = 0.042) and accounted for 34.9% of the variance (Nagelkerke R² = 0.349). FDP thickness remained a strong predictor (B = 0.402, SE = 0.113, OR = 1.495, 95% CI [1.203, 1.857], p < 0.001), while the median nerve thickness also became more influential (B = 0.418, SE = 0.217, OR = 1.519, 95% CI [0.994, 2.324], p = 0.054). Interestingly, the thickness of the pronator teres showed a negative association with the likelihood of being a sport climber (B = -0.305, SE = 0.158, OR = 0.737, 95% CI [0.538, 1.008], p = 0.054) (Table 3 and Table 4 ). Overall, the final model demonstrated a good fit, with a McFadden R² of 0.227, a Nagelkerke R² of 0.349, and a Tjur R² of 0.289 (Table 3 ). The model's predictive performance was further supported by the ROC analysis, yielding an area under the curve (AUC) of 0.814, indicating excellent discriminative ability. The model achieved an accuracy of 82.0%, a sensitivity of 58.8%, and a specificity of 93.9%. (Fig. 3 ) Multicollinearity diagnostics indicated acceptable tolerance values for all included predictors, suggesting no substantial multicollinearity in the model. Specifically, the Flexor Digitorum Profundus had a tolerance of 0.747 (VIF = 1.340), the Median Nerve showed a tolerance of 0.786 (VIF = 1.273), and the Pronator Teres presented a tolerance of 0.671 (VIF = 1.491). Residual diagnostics confirmed the absence of significant autocorrelation (Durbin-Watson = 2.354). Discussion This study aimed to identify sex-related differences in forearm muscle and nerve morphology among climbers and to explore potential anatomical predictors of climbing discipline. Significant differences in muscle thickness were observed between sexes for all muscles assessed brachioradialis, pronator teres, flexor digitorum superficialis, flexor digitorum profundus and pronator quadratus, except for the radial nerve. These findings suggest that sex plays a central role in anatomical adaptation to climbing stress, while neither limb dominance nor the interaction between sex and dominance exerted statistically significant effects. The greater muscle thickness observed in male climbers is consistent with previous studies linking male sex to increased hypertrophy, attributed to hormonal factors specifically circulating testosterone levels that are 15–20 times higher than those of females from puberty onward and to higher training loads in men, which facilitate greater muscle gains ( 18 , 19 ). A systematic review indicated a significant association between male sex and a higher risk of overuse injuries, which may be linked to men achieving higher climbing grades and accumulating greater experience over time ( 7 ). In contrast, female climbers exhibited a higher rate of traumatic injuries. Although no studies to date have directly linked forearm muscle thickness to sex, the greater muscle thickness observed in male participants in this study could be partially explained by their significantly higher values in height, weight, and BMI compared to females factors that may influence overall muscular development. A greater median nerve thickness was also observed in male climbers, in contrast to the radial nerve, which showed no sex-related differences. This disparity may be explained by the anatomical pathway and mechanical compression points each nerve encounters during climbing. Specifically, the median nerve passes through the carpal tunnel and is subjected to compressive forces during repetitive gripping maneuvers, which may induce adaptive thickening in response to chronic mechanical stress ( 20 ). The MANOVA analysis confirmed that sex was the primary determinant of morphological differences, with no significant effects observed for limb dominance or its interaction with sex. This suggests that, although climbing is a bilateral activity, anatomical adaptations are more strongly driven by sex-related physiological factors than by preferential use of one side of the body. Regarding climbing style, the hierarchical logistic regression analysis identified the flexor digitorum profundus thickness as the strongest anatomical predictor. Climbers with greater FDP thickness were more likely to specialize in sport climbing compared to bouldering. This relationship aligns with the biomechanical demands of sport climbing, which is characterized by longer routes and endurance requirements involving sustained isometric contractions of the deep finger flexors ( 21 , 22 ). Increased FDP development may reflect a functional adaptation to prolonged gripping efforts. Jonathan Leung identified in his study that climbing injuries are primarily due to overuse and most frequently affect the upper limbs. Moreover, he was able to differentiate injury prevalence based on climbing discipline ( 23 ). Boulder climbers showed a higher incidence of traumatic injuries, particularly in the ankles and knees, as a result of falls from height. In contrast, sport climbing was associated predominantly with overuse injuries, especially affecting the fingers, elbows, and shoulders, due to repetitive movements, finger overload, and excessive use of maximal grip force. The inclusion of median nerve thickness in the predictive model moderately increased its explanatory power, suggesting a possible role of neural adaptations or stress-induced changes in differentiating climbing disciplines. Although the effect did not reach conventional levels of statistical significance (p = 0.054), the observed trend justifies further exploration in future studies involving larger samples or climbers at higher competitive levels. This is consistent with previous findings indicating that chronic mechanical compression, such as that experienced during repetitive gripping, can induce measurable nerve thickening, especially in peripheral nerves exposed to repetitive strain ( 24 ). Similarly, pronator teres thickness showed a negative association with sport climbing, which may reflect greater development in boulder climbers. This population often performs explosive, high-intensity upper limb movements requiring powerful forearm pronation and elbow stabilization, movements in which the pronator teres plays a key functional role ( 25 ). The final regression model demonstrated high classification accuracy (82%), excellent discriminative ability (AUC = 0.814), and no issues with multicollinearity or autocorrelation, reinforcing the robustness of the findings. Collectively, these results provide preliminary evidence that ultrasound-measured anatomical variables particularly the thickness of the flexor digitorum profundus and the median nerve could serve as non-invasive indicators of climbing specialization. Limitations This study presents important methodological considerations that should be considered when interpreting the results. While musculoskeletal ultrasound (USI) provided a reliable and non-invasive method for assessing forearm muscle and nerve morphology, it did not include direct measurements of muscle strength or functional capacity. Therefore, the relationship between anatomical adaptations and climbing performance remains partially unexplored. Future research should integrate objective assessments of grip strength or climbing-specific tasks to clarify these associations. Another limitation lies in the static nature of ultrasound imaging. Measurements were taken under resting conditions, which may not fully reflect the functional demands imposed during climbing. The integration of surface electromyography (sEMG) in future protocols could offer additional insight into neuromuscular activation patterns under load or during sport-specific gestures. Finally, although climbers were grouped based on their predominant climbing discipline (bouldering vs. sport climbing), the degree of cross-participation between styles was not systematically recorded. This overlap may have influenced the morphological differences observed between groups. Conclusions The findings of this study revealed significant sex-based differences in forearm muscle and median nerve thickness among climbers. Male participants exhibited greater thickness across all assessed muscles including the brachioradialis, pronator teres, flexor digitorum superficialis, flexor digitorum profundus and pronator quadratus as well as the median nerve. In contrast, no significant differences were observed for the radial nerve. No effects were found related to limb dominance, suggesting that anatomical adaptations in climbers occur bilaterally, regardless of preferential arm use. This supports the notion that climbing imposes symmetrical demands on the upper limbs. Regarding climbing discipline, the FDP thickness emerged as the most consistent anatomical predictor of sport climbing specialization. Greater FDP thickness was associated with a higher likelihood of practicing lead climbing over bouldering, and this association remained significant after controlling for other morphological variables. Median nerve thickness also showed a positive trend toward sport climbing, while pronator teres thickness was inversely associated, potentially indicating different muscular adaptation patterns in bouldering athletes. These results underscore the value of ultrasound-based assessments in identifying structural adaptations linked to sex and climbing style, which may inform future approaches in training, screening, and injury prevention for climbers. Declarations Author Contribution Conceptualization: H.C.-B., D.L.-L., C.R.-M.Methodology: H.C.-B., Á.G.-F., M.G.-M., D.M.-M., G.J.-C.Formal analysis: H.C.-B., M.B.-A., M.E.-R., D.J.-P.Investigation / Data collection: M.B.-A., M.E.-R., D.J.-P., Á.G.-F., M.G.-M., D.M.-M., G.J.-C.Visualization (figures, tables): H.C.-B., M.B.-A., Á.G.-F.Writing – original draft: H.C.-B.Writing – review & editing: M.B.-A., M.E.-R., D.J.-P., Á.G.-F., M.G.-M., D.M.-M., G.J.-C., D.L.-L., C.R.-M.Supervision: D.L.-L., C.R.-M.Project administration: H.C.-B., C.R.-M.All authors read and approved the final manuscript. Data Availability The datasets generated and/or analysed during the current study are not publicly available due to privacy and ethical restrictions but are available from the corresponding author on reasonable request. Funding This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors. 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Brachioradialis and pronator teres muscle thickness. B.\u003cstrong\u003e \u003c/strong\u003eFlexor digitorum superficialis muscle thickness (yellow line), flexor digitorum profundus thickness (green line) and median nerve cross-sectional area (yellow circle). C. Pronator quadratus muscle thickness. D. Radial nerve cross-sectional area (yellow circle).\u003c/p\u003e","description":"","filename":"Figure1.png","url":"https://assets-eu.researchsquare.com/files/rs-7530539/v1/04bb26b7531d7316f26d7141.png"},{"id":93014683,"identity":"ef63994e-e726-4c6b-b027-f967bf924d52","added_by":"auto","created_at":"2025-10-08 07:40:04","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":636734,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eMuscle and Nerve Thickness by Sex and Dominant Side.\u003c/strong\u003e Violin plots showing the distribution, median, and interquartile range for muscle (brachioradialis, pronator teres, flexor digitorum superficialis, flexor digitorum profundus, pronator quadratus) and nerve (radial nerve, median nerve) thickness measurements, separated by sex (male, female) and dominant side (dominant, non-dominant). Dominant sides are highlighted in green, while non-dominant sides are in gray.\u003c/p\u003e","description":"","filename":"Figure2.png","url":"https://assets-eu.researchsquare.com/files/rs-7530539/v1/4075f5109248cb5ea3082281.png"},{"id":93013157,"identity":"e90a9616-5278-4547-bf43-070a2133bf9a","added_by":"auto","created_at":"2025-10-08 07:24:05","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":259247,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eReceiver Operating Characteristic (ROC) and Precision-Recall (PR) Curves for the Logistic Regression Model.\u003c/strong\u003e Legend: The ROC curve illustrates the true positive rate (sensitivity) versus the false positive rate (1-specificity) at various threshold settings, providing a measure of the overall model performance with an AUC (Area Under the Curve) of 0.814, indicating excellent discrimination. The PR curve, plotted alongside, reflects the precision (positive predictive value) versus recall (sensitivity) across threshold levels\u003c/p\u003e","description":"","filename":"Figure3.png","url":"https://assets-eu.researchsquare.com/files/rs-7530539/v1/27007a7e27ee64b2a9c65541.png"},{"id":93014685,"identity":"34757d43-156d-46c9-8ef5-cfba987f3da1","added_by":"auto","created_at":"2025-10-08 07:40:11","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":5042727,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7530539/v1/3a19348c-3fb6-4f72-8d5e-c743935994d1.pdf"},{"id":93013032,"identity":"c5288dfd-38b9-4e39-ba51-bf86ba7bd860","added_by":"auto","created_at":"2025-10-08 07:23:54","extension":"xlsx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":24927,"visible":true,"origin":"","legend":"","description":"","filename":"rawdata.xlsx","url":"https://assets-eu.researchsquare.com/files/rs-7530539/v1/e08bf84a01e0550e74c58fc5.xlsx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Sex-based forearm morphology in climbers: an ultrasound study and it´s predictive value for climbing style","fulltext":[{"header":"Introduction","content":"\u003cp\u003eSport climbing, practiced in both indoor and outdoor settings, involves the repetitive execution of static and dynamic movements that require muscular strength, balance, and postural control. This discipline has experienced a significant increase in popularity, culminating in its inclusion as an official Olympic sport at the Tokyo 2020 Games (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e). In Spain, according to the Spanish Federation of Mountain and Climbing Sports (FEDME), sport climbing rack as the fifth most practiced sport, with over 290,000 registered federated athletes and an extensive network of specialized climbing facilities.\u003c/p\u003e\u003cp\u003eSport climbing includes three primary modalities, speed climbing, lead climbing, and bouldering. Regardless of the discipline, climbing involves repetitive static and dynamic movements that demand significant muscular strength, postural control, and neuromuscular coordination, particularly of the upper limbs (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e). These biomechanical requirements, combined with the inclined surfaces and frequent suspension of the climber's body weight from the upper extremities, lead to substantial loading of the forearm, hand, and fingers (\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eWhile grading systems vary across countries and disciplines, the International Rock Climbing Research Association (IRCRA) has proposed a standardized classification system based on performance level: novice, intermediate, advanced, elite, and high elite (\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e). In this study, climbing ability was categorized using the French scale grading system, which applies a combination of numbers and letters in both lead climbing and bouldering to represent route difficulty (\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eDue to the biomechanical demands of sport climbing such as sustained gripping on inclined surfaces and prolonged suspension of body weight using the upper limbs here is a significant mechanical load placed on the musculoskeletal structures of the upper extremity. This sustained load has been associated with a high prevalence of overuse injuries in climbers. A systematic review by Quarmby et al. reported that up to 93% of climbing-related injuries are classified as overuse injuries, with the fingers being the most frequently affected anatomical region (\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e). Similarly, a descriptive study conducted by McDonald et al. found that 39.4% of injuries occurred in the fingers, followed by 17.7% in the shoulders and 15.6% in the elbows, with tendinous strains, muscle strains, and tendinopathies being the most commonly reported diagnoses, accounting for 45.8% of all cases (\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eOne of the most commonly used grip techniques in climbing, particularly on small holds, is the crimp grip, in which the proximal interphalangeal joint is flexed to approximately 90 degrees and the distal interphalangeal joint remains in hyperextension. This grip configuration has been associated with increased mechanical stress on the flexor tendon complex, especially the flexor digitorum superficialis and flexor digitorum profundus muscles, which play a key role in sustaining body weight during climbing tasks (\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eClimbing performance has been the subject of numerous studies that have examined both physical and psychological attributes, including strength, endurance, flexibility, and mental resilience. Among the physical assessments, grip strength and muscular endurance tests have demonstrated strong validity and reliability in evaluating climbing-specific capabilities (\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e). These measurements are particularly relevant given the repetitive and high-load nature of gripping during training and competition.\u003c/p\u003e\u003cp\u003eDespite the growing interest in functional and morphological adaptations in climbers, musculoskeletal ultrasound has not yet been widely employed as an analytical tool in climbing research. Currently, there are no published studies that use ultrasound imaging to explore associations between anatomical structures and sport-specific factors, such as climbing discipline, performance level, training history, or injury occurrence in the upper limbs (\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eThe forearm region plays a fundamental role in climbing biomechanics, as it houses the primary muscle-tendon units responsible for generating and sustaining grip force (\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e). Given the cumulative loading experienced during prolonged climbing sessions, this segment is considered particularly vulnerable to overuse injuries and may present detectable morphological adaptations related to training exposure and athletic profile.\u003c/p\u003e\u003cp\u003eIn this context, musculoskeletal ultrasound may provide valuable information regarding anatomical changes induced by sport-specific demands and potential risk factors associated with overuse injuries in this population. Furthermore, this tool enables the detailed description of structural findings in climbers and the exploration of possible correlations with demographic variables, such as sex, age, and climbing discipline, contributing to the development of targeted preventive and clinical strategies.\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003eStudy design\u003c/h2\u003e\u003cp\u003eThis observational cross-sectional study was carried out between December 2024 and February 2025, in accordance with the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines (\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e).\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003eParticipants\u003c/h3\u003e\n\u003cp\u003eA total of 50 recreational rock climbers were included in this study (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The sample was divided into two groups according to sex: male (n\u0026thinsp;=\u0026thinsp;25) and female (n\u0026thinsp;=\u0026thinsp;25) participants. Inclusion criteria comprised male and female climbers aged between 18 and 60 years, with regular climbing practice for at least the previous three months. Exclusion criteria included any upper limb musculoskeletal injury occurring within the last three months, and history of surgery within the past six months.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eParticipant Characteristics\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"3\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eVariable\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eMean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD or n (%)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAge (years)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e37.68\u0026thinsp;\u0026plusmn;\u0026thinsp;8.52\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eHeight (m)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1.71\u0026thinsp;\u0026plusmn;\u0026thinsp;0.09\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eWeight (kg)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e65.14\u0026thinsp;\u0026plusmn;\u0026thinsp;11.85\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eBMI (kg/m\u0026sup2;)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e22.29\u0026thinsp;\u0026plusmn;\u0026thinsp;3.09\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eYears of Experience\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e3.52\u0026thinsp;\u0026plusmn;\u0026thinsp;3.05\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eSex\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMale\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e33 (66%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFemale\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e17 (34%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eTraining Volume\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1-1.5 h/week\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2 (4%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e2-2.5 h/week\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e10 (20%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e3-3.5 h/week\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e9 (18%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e4\u0026ndash;5 h/week\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e8 (16%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u0026gt;\u0026thinsp;5 h/week\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e11 (22%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eExternal Activity\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eYes\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e38 (76%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNo\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e12 (24%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eClimbing Type\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eBoulder\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e33 (66%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSport Climbing\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e17 (34%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eClimbing Grade Boulder\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e4 (8%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e16 (32%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e11 (22%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2 (4%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eClimbing Grade Sport\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e5 (10%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e8 (16%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e4 (8%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003ePrevious Upper Limb Injury\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eYes\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e20 (40%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNo\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e30 (60%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eMANOVA: Muscle and Nerve Measurements by Sex and Dominant Side.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"8\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eVariable\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003eDominant\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e\u003cp\u003eNon-Dominant\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eSex (F, p-value)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eDominant Side (F, p-value)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c8\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eSex ✻ Dominant Side (F, p-value)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eMale\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eFemale\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eMale\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eFemale\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eBrachioradialis\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e18.31\u0026thinsp;\u0026plusmn;\u0026thinsp;2.56\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e\u003cp\u003e12.36\u0026thinsp;\u0026plusmn;\u0026thinsp;1.82\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e\u003cp\u003e18.27\u0026thinsp;\u0026plusmn;\u0026thinsp;2.83\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e\u003cp\u003e12.23\u0026thinsp;\u0026plusmn;\u0026thinsp;1.71\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e\u003cb\u003e137.079, \u0026lt;\u0026thinsp;0.001\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e0.020, 0.887\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e0.008, 0.930\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003ePronator Teres\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e11.69\u0026thinsp;\u0026plusmn;\u0026thinsp;1.85\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e\u003cp\u003e9.33\u0026thinsp;\u0026plusmn;\u0026thinsp;1.59\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e\u003cp\u003e11.08\u0026thinsp;\u0026plusmn;\u0026thinsp;1.65\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e\u003cp\u003e9.09\u0026thinsp;\u0026plusmn;\u0026thinsp;1.38\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e\u003cb\u003e37.985, \u0026lt;\u0026thinsp;0.001\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e2.098, 0.151\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e0.280, 0.598\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eFlexor Digitorum Superficialis\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e13.23\u0026thinsp;\u0026plusmn;\u0026thinsp;2.55\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e\u003cp\u003e10.07\u0026thinsp;\u0026plusmn;\u0026thinsp;1.41\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e\u003cp\u003e12.75\u0026thinsp;\u0026plusmn;\u0026thinsp;1.81\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e\u003cp\u003e9.40\u0026thinsp;\u0026plusmn;\u0026thinsp;1.52\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e\u003cb\u003e59.675, \u0026lt;\u0026thinsp;0.001\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e1.870, 0.175\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e0.049, 0.826\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eFlexor Digitorum Profundus\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e15.21\u0026thinsp;\u0026plusmn;\u0026thinsp;2.28\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e\u003cp\u003e11.67\u0026thinsp;\u0026plusmn;\u0026thinsp;1.89\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e\u003cp\u003e15.46\u0026thinsp;\u0026plusmn;\u0026thinsp;2.35\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e\u003cp\u003e10.97\u0026thinsp;\u0026plusmn;\u0026thinsp;1.72\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e\u003cb\u003e77.502, \u0026lt;\u0026thinsp;0.001\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e0.033, 0.857\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e1.090, 0.299\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003ePronator Quadratus\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e13.67\u0026thinsp;\u0026plusmn;\u0026thinsp;1.63\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e\u003cp\u003e10.12\u0026thinsp;\u0026plusmn;\u0026thinsp;1.53\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e\u003cp\u003e13.44\u0026thinsp;\u0026plusmn;\u0026thinsp;1.84\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e\u003cp\u003e9.68\u0026thinsp;\u0026plusmn;\u0026thinsp;1.08\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e\u003cb\u003e115.368, \u0026lt;\u0026thinsp;0.001\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e0.867, 0.354\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e0.092, 0.762\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eRadial Nerve\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e8.59\u0026thinsp;\u0026plusmn;\u0026thinsp;1.32\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e\u003cp\u003e8.15\u0026thinsp;\u0026plusmn;\u0026thinsp;1.08\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e\u003cp\u003e8.86\u0026thinsp;\u0026plusmn;\u0026thinsp;1.54\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e\u003cp\u003e8.98\u0026thinsp;\u0026plusmn;\u0026thinsp;1.41\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e0.317, 0.575\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e2.786, 0.098\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e0.920, 0.340\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eMedian Nerve\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e10.69\u0026thinsp;\u0026plusmn;\u0026thinsp;1.28\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e\u003cp\u003e9.99\u0026thinsp;\u0026plusmn;\u0026thinsp;0.80\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e\u003cp\u003e10.16\u0026thinsp;\u0026plusmn;\u0026thinsp;2.20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e\u003cp\u003e9.03\u0026thinsp;\u0026plusmn;\u0026thinsp;1.02\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e\u003cb\u003e7.752, 0.006\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e\u003cb\u003e4.718, 0.032\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e0.439, 0.509\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"8\"\u003eNotes: Muscle and nerve measurements are in millimeters (mm). Statistical significance set at p\u0026thinsp;\u0026lt;\u0026thinsp;0.05 (bold).\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\n\u003ch3\u003eSample size calculation\u003c/h3\u003e\n\u003cp\u003eThe sample size was calculated using G*Power 3.1.9.2 software, based on preliminary data from a pilot study (n\u0026thinsp;=\u0026thinsp;20) assessing the thickness of the flexor digitorum profundus muscle (mm). The pilot included two independent groups of climbers: 10 males (mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD: 6.2\u0026thinsp;\u0026plusmn;\u0026thinsp;1.4 mm) and 10 females (5.1\u0026thinsp;\u0026plusmn;\u0026thinsp;1.3 mm). A two-tailed hypothesis was applied, with an effect size (Cohen\u0026rsquo;s \u003cem\u003ed\u003c/em\u003e) of 0.83, an alpha level of 0.05, statistical power (1\u0026ndash;β) of 0.80, and an allocation ratio of 1. Based on these parameters, the minimum required sample size was determined to be 50 participants, with 25 in each group.\u003c/p\u003e\n\u003ch3\u003eEthical considerations\u003c/h3\u003e\n\u003cp\u003e This study received ethical approval from the Ethics Committee of the European University. All participants provided written informed consent prior to their inclusion in the research. The procedures followed were in accordance with the ethical principles outlined in the Declaration of Helsinki for research involving human subjects.\u003c/p\u003e\n\u003ch3\u003eData Availability\u003c/h3\u003e\n\u003cp\u003eThe datasets generated and/or analysed during the current study are not publicly available due to privacy and ethical restrictions but are available from the corresponding author on reasonable request.\u003c/p\u003e\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\u003ch2\u003eData Collection Instruments and Ultrasonography Procedure:\u003c/h2\u003e\u003cp\u003eA digital questionnaire was administered to collect detailed information on participants\u0026rsquo; anthropometric characteristics, history of upper limb injuries, and physical activity related or unrelated to climbing. Participant confidentiality was ensured throughout the study.\u003c/p\u003e\u003cp\u003eUltrasound measurements were recorded in a custom-designed database developed by the research team. A SonoScape E2 ultrasound system (SonoScape, Madrid, Spain), conductive gel, a portable examination table, and disposable paper were used during the assessment process. All participants were evaluated in a seated position, with the elbow flexed to approximately 120\u0026deg;, ensuring consistency in posture throughout data collection.\u003c/p\u003e\u003cp\u003eFor the assessment of muscular structures, the brachioradialis muscle was evaluated with the forearm in pronation and supported on the examination table. The transducer was placed transversely over the supracondylar region, and muscle thickness was measured where the muscle belly ran parallel to the bone surface. To examine the pronator teres, the forearm was positioned in supination. The transducer was first placed over the brachioradialis and then rotated and shifted medially and distally along the forearm (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eA). Activation was confirmed by asking the participant to pronate the forearm (\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe flexor digitorum superficialis and flexor digitorum profundus muscles were also examined with the forearm in supination. The transducer was positioned along the middle third of the forearm, and correct identification of each muscle was verified by requesting metacarpophalangeal joint flexion for the superficial flexor (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eB) and distal phalanx flexion for the deep flexor (\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e). The pronator quadratus was assessed by placing the probe transversely at the midpoint between the radius and ulna in the same supine position, and vertical muscle thickness was measured (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eC).\u003c/p\u003e\u003cp\u003eRegarding the peripheral nerves, the median nerve was evaluated with the forearm in supination and the shoulder slightly externally rotated. The nerve was identified on the medial aspect of the proximal third of the forearm, near the elbow joint (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eB). The radial nerve was located by sliding the transducer slightly distally, identifying it between the brachioradialis and pronator teres muscles, and its cross-sectional area was recorded (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eD) (\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec9\" class=\"Section2\"\u003e\u003ch2\u003eStatistical Analysis\u003c/h2\u003e\u003cp\u003eThe statistical analyses for this study were conducted using JASP (Version 0.17.3) and SPSS (Version 29, IBM Corp., Armonk, NY, USA) for Windows. The analyses included descriptive statistics, normality tests, independent samples t-tests, Mann-Whitney U tests, multivariate analysis of variance (MANOVA), and hierarchical logistic regression, following the STROBE guidelines for observational studies.\u003c/p\u003e\u003cp\u003eDescriptive statistics were calculated for continuous variables. These variables were summarized as means and standard deviations (SD) for normally distributed data, and as medians and interquartile ranges (IQR) for non-normally distributed data. Proportions were reported for categorical variables. To assess normality, the Shapiro-Wilk test was used, with a significance threshold set at p\u0026thinsp;\u0026lt;\u0026thinsp;0.05, indicating a deviation from the normal distribution. Homogeneity of variances was evaluated using Levene's test, with p\u0026thinsp;\u0026lt;\u0026thinsp;0.05 suggesting unequal variances. Independent samples t-tests were conducted to compare means between male and female climbers for normally distributed variables. Effect sizes were calculated using Cohen's d, with values below 0.2 indicating a small effect, 0.2 to 0.5 a medium effect, and above 0.8 a large effect. For non-normally distributed data, Mann-Whitney U tests were employed, with effect sizes reported as rank biserial correlations.\u003c/p\u003e\u003cp\u003eA MANOVA was conducted to examine the main effects of sex, dominant side, and their interaction on muscle and nerve thickness. The analysis used Pillai\u0026rsquo;s Trace as the multivariate test statistic. Pillai\u0026rsquo;s Trace values closer to 1 indicate stronger multivariate effects. Univariate ANOVAs were then conducted for each muscle and nerve to identify significant differences within the MANOVA model. Post-hoc pairwise comparisons were realized for significant main effects, using 95% confidence intervals (CI) to estimate the precision of the observed differences. Bonferroni correction was applied to adjust for multiple comparisons, maintaining a family-wise error rate of 0.05.\u003c/p\u003e\u003cp\u003eHierarchical logistic regression models were developed to identify anatomical and morphological predictors of climbing style (sport climbing vs. bouldering). Predictors were entered in a stepwise manner, with model fit assessed using the likelihood ratio (Δχ\u0026sup2;) test at each step. Model performance was evaluated using McFadden's R\u0026sup2;, Nagelkerke's R\u0026sup2;, Tjur's R\u0026sup2;, and the area under the receiver operating characteristic (ROC) curve (AUC). Multicollinearity was assessed using variance inflation factors (VIF), with a threshold of 5 indicating potential multicollinearity. Residual diagnostics included the Durbin-Watson test to assess autocorrelation. Assumptions for each analysis were checked, including normality, homogeneity of variance, multicollinearity, and independence of residuals. Any violations were addressed accordingly to ensure the robustness of the results.\u003c/p\u003e\u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eThe baseline characteristics of the 50 climbers included in the study are presented in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. No significant differences were observed in age between males (37.24\u0026thinsp;\u0026plusmn;\u0026thinsp;9.05 years) and females (38.53\u0026thinsp;\u0026plusmn;\u0026thinsp;7.45 years) (t(98) = -0.714, p\u0026thinsp;=\u0026thinsp;0.477, d = -0.151). In contrast, significant differences were found for height, weight, and BMI. Males had significantly greater height (1.74\u0026thinsp;\u0026plusmn;\u0026thinsp;0.07 m) than females (1.63\u0026thinsp;\u0026plusmn;\u0026thinsp;0.07 m), (t(98)\u0026thinsp;=\u0026thinsp;8.092, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001, d\u0026thinsp;=\u0026thinsp;1.708). Similarly, males exhibited higher weight (70.12\u0026thinsp;\u0026plusmn;\u0026thinsp;10.69 kg) compared to females (55.47\u0026thinsp;\u0026plusmn;\u0026thinsp;7.09 kg) (t(98)\u0026thinsp;=\u0026thinsp;7.205, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001, d\u0026thinsp;=\u0026thinsp;1.521). Regarding BMI, males (23.04\u0026thinsp;\u0026plusmn;\u0026thinsp;3.30 kg/m\u0026sup2;) presented significantly higher values than females (20.82\u0026thinsp;\u0026plusmn;\u0026thinsp;1.95 kg/m\u0026sup2;) (t(98)\u0026thinsp;=\u0026thinsp;3.606, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001, d\u0026thinsp;=\u0026thinsp;0.761).\u003c/p\u003e\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e\u003ch2\u003eMANOVA effects\u003c/h2\u003e\u003cp\u003eThe MANOVA revealed a significant main effect of sex (Pillai\u0026rsquo;s Trace\u0026thinsp;=\u0026thinsp;0.689, F(7, 90)\u0026thinsp;=\u0026thinsp;28.437, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), while the main effect of dominant side (Pillai\u0026rsquo;s Trace\u0026thinsp;=\u0026thinsp;0.098, F(7, 90)\u0026thinsp;=\u0026thinsp;1.394, p\u0026thinsp;=\u0026thinsp;0.218) and the interaction between sex and dominant side (Pillai\u0026rsquo;s Trace\u0026thinsp;=\u0026thinsp;0.033, F(7, 90)\u0026thinsp;=\u0026thinsp;0.443, p\u0026thinsp;=\u0026thinsp;0.872) were not statistically significant, indicating that the differences were primarily driven by sex rather than limb dominance or the interaction between these factors.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec12\" class=\"Section2\"\u003e\u003ch2\u003eSex\u003c/h2\u003e\u003cp\u003eMuscle thickness differences were significant for the Brachioradialis (F\u0026thinsp;=\u0026thinsp;137.079, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), Pronator Teres (F\u0026thinsp;=\u0026thinsp;37.985, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), Flexor Digitorum Superficialis (F\u0026thinsp;=\u0026thinsp;59.675, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), Flexor Digitorum Profundus (F\u0026thinsp;=\u0026thinsp;77.502, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), Pronator Quadratus (F\u0026thinsp;=\u0026thinsp;115.368, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), and Median Nerve (F\u0026thinsp;=\u0026thinsp;7.752, p\u0026thinsp;=\u0026thinsp;0.006). In contrast, the Radial Nerve did not show a significant sex difference (F\u0026thinsp;=\u0026thinsp;0.317, p\u0026thinsp;=\u0026thinsp;0.575).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec13\" class=\"Section2\"\u003e\u003ch2\u003eDominant Side\u003c/h2\u003e\u003cp\u003eThe main effect for dominant side was not statistically significant for any of the muscles or nerves assessed. The Brachioradialis (F\u0026thinsp;=\u0026thinsp;0.020, p\u0026thinsp;=\u0026thinsp;0.887), Pronator Teres (F\u0026thinsp;=\u0026thinsp;2.098, p\u0026thinsp;=\u0026thinsp;0.151), Flexor Digitorum Superficialis (F\u0026thinsp;=\u0026thinsp;1.870, p\u0026thinsp;=\u0026thinsp;0.175), Flexor Digitorum Profundus (F\u0026thinsp;=\u0026thinsp;0.033, p\u0026thinsp;=\u0026thinsp;0.857), Pronator Quadratus (F\u0026thinsp;=\u0026thinsp;0.867, p\u0026thinsp;=\u0026thinsp;0.354), Radial Nerve (F\u0026thinsp;=\u0026thinsp;2.786, p\u0026thinsp;=\u0026thinsp;0.098), and Median Nerve (F\u0026thinsp;=\u0026thinsp;4.718, p\u0026thinsp;=\u0026thinsp;0.032) did not show significant differences based on the dominant side.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec14\" class=\"Section2\"\u003e\u003ch2\u003eInteraction of Sex and Dominant Side\u003c/h2\u003e\u003cp\u003eSimilarly, the interaction between sex and dominant side was not statistically significant for any of the muscles or nerves measured. The Brachioradialis (F\u0026thinsp;=\u0026thinsp;0.008, p\u0026thinsp;=\u0026thinsp;0.930), Pronator Teres (F\u0026thinsp;=\u0026thinsp;0.280, p\u0026thinsp;=\u0026thinsp;0.598), Flexor Digitorum Superficialis (F\u0026thinsp;=\u0026thinsp;0.049, p\u0026thinsp;=\u0026thinsp;0.826), Flexor Digitorum Profundus (F\u0026thinsp;=\u0026thinsp;1.090, p\u0026thinsp;=\u0026thinsp;0.299), Pronator Quadratus (F\u0026thinsp;=\u0026thinsp;0.092, p\u0026thinsp;=\u0026thinsp;0.762), Radial Nerve (F\u0026thinsp;=\u0026thinsp;0.920, p\u0026thinsp;=\u0026thinsp;0.340), and Median Nerve (F\u0026thinsp;=\u0026thinsp;0.439, p\u0026thinsp;=\u0026thinsp;0.509) all showed no significant interaction effects. (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec15\" class=\"Section2\"\u003e\u003ch2\u003ePost-Hoc Analysis\u003c/h2\u003e\u003cp\u003ePost-hoc comparisons revealed that the Brachioradialis in males was significantly thicker than in females for both the dominant (MD\u0026thinsp;=\u0026thinsp;5.95 mm, 95% CI [4.86, 7.04]) and non-dominant sides (MD\u0026thinsp;=\u0026thinsp;6.04 mm, 95% CI [4.87, 7.21]). Similarly, the Pronator Teres in males was significantly thicker than in females for both the dominant (MD\u0026thinsp;=\u0026thinsp;2.36 mm, 95% CI [1.50, 3.22]) and non-dominant sides (MD\u0026thinsp;=\u0026thinsp;1.99 mm, 95% CI [1.17, 2.81]). For the Flexor Digitorum Superficialis, males also had greater thickness on both the dominant (MD\u0026thinsp;=\u0026thinsp;3.16 mm, 95% CI [2.15, 4.16]) and non-dominant sides (MD\u0026thinsp;=\u0026thinsp;3.35 mm, 95% CI [2.34, 4.36]). The Flexor Digitorum Profundus showed a similar pattern, with significant differences for both dominant (MD\u0026thinsp;=\u0026thinsp;3.54 mm, 95% CI [2.41, 4.67]) and non-dominant sides (MD\u0026thinsp;=\u0026thinsp;4.49 mm, 95% CI [3.30, 5.68]). The Pronator Quadratus also demonstrated significant sex differences for both dominant (MD\u0026thinsp;=\u0026thinsp;3.55 mm, 95% CI [2.67, 4.43]) and non-dominant sides (MD\u0026thinsp;=\u0026thinsp;3.76 mm, 95% CI [2.90, 4.62]). Finally, the Median Nerve was significantly thicker in males for the dominant (MD\u0026thinsp;=\u0026thinsp;0.70 mm, 95% CI [0.20, 1.20]) and non-dominant sides (MD\u0026thinsp;=\u0026thinsp;1.13 mm, 95% CI [0.44, 1.82]). In contrast, no significant differences were observed for the Radial Nerve on either the dominant (MD\u0026thinsp;=\u0026thinsp;0.44 mm, 95% CI [-0.15, 1.03]) or non-dominant side (MD = -0.12 mm, 95% CI [-0.70, 0.46]).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec16\" class=\"Section2\"\u003e\u003ch2\u003eLogistic Regression\u003c/h2\u003e\u003cp\u003eA hierarchical logistic regression analysis was conducted to identify the anatomical and morphological predictors of sport climbing style compared to bouldering tstyle\u003c/p\u003e\u003cp\u003eIn the initial model (M₁), only the thickness of the flexor digitorum profundus (FDP) was included as a predictor. This variable significantly improved model fit (Δχ\u0026sup2;(\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e)\u0026thinsp;=\u0026thinsp;21.709, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) and accounted for 27.0% of the variance (Nagelkerke R\u0026sup2; = 0.270). The FDP thickness was a significant positive predictor (B\u0026thinsp;=\u0026thinsp;0.394, SE\u0026thinsp;=\u0026thinsp;0.096, OR\u0026thinsp;=\u0026thinsp;1.482, 95% CI [1.231, 1.784], p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), indicating that for each 1 mm increase in FDP thickness, the odds of being a sport climber increased by approximately 48.2% (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e and Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eLogistic Regression Model Summary for Predicting Climbing type\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"23\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c11\" colnum=\"11\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c12\" colnum=\"12\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c13\" colnum=\"13\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c14\" colnum=\"14\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c15\" colnum=\"15\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c16\" colnum=\"16\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c17\" colnum=\"17\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c18\" colnum=\"18\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c19\" colnum=\"19\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c20\" colnum=\"20\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c21\" colnum=\"21\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c22\" colnum=\"22\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c23\" colnum=\"23\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003eModel\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e\u003cp\u003eDeviance\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e\u003cp\u003eAIC\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c9\" namest=\"c8\"\u003e\u003cp\u003eBIC\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c11\" namest=\"c10\"\u003e\u003cp\u003edf\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c13\" namest=\"c12\"\u003e\u003cp\u003eΔΧ\u0026sup2;\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c15\" namest=\"c14\"\u003e\u003cp\u003ep\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c17\" namest=\"c16\"\u003e\u003cp\u003eMcFadden R\u0026sup2;\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c19\" namest=\"c18\"\u003e\u003cp\u003eNagelkerke R\u0026sup2;\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c21\" namest=\"c20\"\u003e\u003cp\u003eTjur R\u0026sup2;\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c23\" namest=\"c22\"\u003e\u003cp\u003eCox \u0026amp; Snell R\u0026sup2;\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eM₀\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e128.207\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e130.207\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e132.812\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e\u003cp\u003e99\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c14\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c15\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c16\"\u003e\u003cp\u003e0.000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c17\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c18\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c19\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c20\"\u003e\u003cp\u003e0.000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c21\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c22\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c23\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eM₁\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e106.498\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e110.498\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e115.708\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e\u003cp\u003e98\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c12\"\u003e\u003cp\u003e21.709\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c14\"\u003e\u003cp\u003e\u0026lt;\u0026nbsp;.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c15\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c16\"\u003e\u003cp\u003e0.169\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c17\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c18\"\u003e\u003cp\u003e0.270\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c19\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c20\"\u003e\u003cp\u003e0.210\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c21\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c22\"\u003e\u003cp\u003e0.195\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c23\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eM₂\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e103.314\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e109.314\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e117.129\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e\u003cp\u003e97\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c12\"\u003e\u003cp\u003e3.184\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c14\"\u003e\u003cp\u003e0.074\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c15\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c16\"\u003e\u003cp\u003e0.194\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c17\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c18\"\u003e\u003cp\u003e0.305\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c19\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c20\"\u003e\u003cp\u003e0.242\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c21\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c22\"\u003e\u003cp\u003e0.220\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c23\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eM₃\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e99.167\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e107.167\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e117.588\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e\u003cp\u003e96\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c12\"\u003e\u003cp\u003e4.147\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c14\"\u003e\u003cp\u003e0.042\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c15\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c16\"\u003e\u003cp\u003e0.227\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c17\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c18\"\u003e\u003cp\u003e0.349\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c19\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c20\"\u003e\u003cp\u003e0.289\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c21\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c22\"\u003e\u003cp\u003e0.252\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c23\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eLogistic Regression Models for Predicting Climbing Type Based on Muscle and Nerve Thickness.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"20\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c11\" colnum=\"11\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c12\" colnum=\"12\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c13\" colnum=\"13\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c14\" colnum=\"14\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c15\" colnum=\"15\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c16\" colnum=\"16\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c17\" colnum=\"17\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c18\" colnum=\"18\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c19\" colnum=\"19\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c20\" colnum=\"20\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colspan=\"13\" nameend=\"c13\" namest=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colspan=\"7\" nameend=\"c20\" namest=\"c14\"\u003e\u003cp\u003eWald Test\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003eModel\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e\u003cp\u003eParameter\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e\u003cp\u003eEstimate\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c8\" namest=\"c7\"\u003e\u003cp\u003eStandard Error\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c10\" namest=\"c9\"\u003e\u003cp\u003eOdds Ratio\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"3\" nameend=\"c13\" namest=\"c11\"\u003e\u003cp\u003ez\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c15\" namest=\"c14\"\u003e\u003cp\u003eWald Statistic\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"3\" nameend=\"c18\" namest=\"c16\"\u003e\u003cp\u003edf\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c20\" namest=\"c19\"\u003e\u003cp\u003ep\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eM₀\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e\u003cb\u003e(Intercept)\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-0.663\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e0.211\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e0.515\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e-3.142\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c14\" namest=\"c13\"\u003e\u003cp\u003e9.873\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c15\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c16\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c17\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c19\" namest=\"c18\"\u003e\u003cp\u003e0.002\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c20\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eM₁\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e\u003cb\u003e(Intercept)\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-6.337\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e1.443\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e0.002\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e-4.392\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c14\" namest=\"c13\"\u003e\u003cp\u003e19.287\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c15\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c16\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c17\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c19\" namest=\"c18\"\u003e\u003cp\u003e\u0026lt;\u0026nbsp;.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c20\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e\u003cb\u003eFlexor Digitorum Profundus\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.394\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e0.096\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e1.482\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e4.080\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c14\" namest=\"c13\"\u003e\u003cp\u003e16.650\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c15\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c16\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c17\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c19\" namest=\"c18\"\u003e\u003cp\u003e\u0026lt;\u0026nbsp;.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c20\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eM₂\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e\u003cb\u003e(Intercept)\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-8.426\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e2.000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e2.192\u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;4\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e-4.212\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c14\" namest=\"c13\"\u003e\u003cp\u003e17.741\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c15\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c16\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c17\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c19\" namest=\"c18\"\u003e\u003cp\u003e\u0026lt;\u0026nbsp;.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c20\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e\u003cb\u003eFlexor Digitorum Profundus\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.330\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e0.100\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e1.391\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e3.289\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c14\" namest=\"c13\"\u003e\u003cp\u003e10.820\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c15\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c16\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c17\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c19\" namest=\"c18\"\u003e\u003cp\u003e0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c20\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e\u003cb\u003eMedian Nerve\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.295\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e0.182\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e1.343\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e1.617\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c14\" namest=\"c13\"\u003e\u003cp\u003e2.616\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c15\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c16\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c17\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c19\" namest=\"c18\"\u003e\u003cp\u003e0.106\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c20\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eM₃\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e\u003cb\u003e(Intercept)\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-7.420\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e2.152\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e5.990\u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;4\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e-3.448\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c14\" namest=\"c13\"\u003e\u003cp\u003e11.888\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c15\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c16\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c17\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c19\" namest=\"c18\"\u003e\u003cp\u003e\u0026lt;\u0026nbsp;.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c20\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e\u003cb\u003eFlexor Digitorum Profundus\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.402\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e0.113\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e1.495\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e3.554\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c14\" namest=\"c13\"\u003e\u003cp\u003e12.628\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c15\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c16\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c17\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c19\" namest=\"c18\"\u003e\u003cp\u003e\u0026lt;\u0026nbsp;.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c20\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e\u003cb\u003eMedian Nerve\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.418\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e0.217\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e1.519\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e1.927\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c14\" namest=\"c13\"\u003e\u003cp\u003e3.712\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c15\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c16\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c17\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c19\" namest=\"c18\"\u003e\u003cp\u003e0.054\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c20\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e\u003cb\u003ePronator Teres\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-0.305\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e0.158\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e0.737\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e-1.927\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c14\" namest=\"c13\"\u003e\u003cp\u003e3.714\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c15\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c16\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c17\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c19\" namest=\"c18\"\u003e\u003cp\u003e0.054\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c20\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eModel 2 (M₂) introduced the median nerve (MN) thickness as an additional predictor. This addition further improved the model fit (Δχ\u0026sup2;(\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e)\u0026thinsp;=\u0026thinsp;3.184, p\u0026thinsp;=\u0026thinsp;0.074), resulting in a Nagelkerke R\u0026sup2; of 0.305, explaining 30.5% of the variance. In this step, FDP thickness remained a significant positive predictor (B\u0026thinsp;=\u0026thinsp;0.330, SE\u0026thinsp;=\u0026thinsp;0.100, OR\u0026thinsp;=\u0026thinsp;1.391, 95% CI [1.136, 1.703], p\u0026thinsp;=\u0026thinsp;0.001), while the median nerve thickness approached significance (B\u0026thinsp;=\u0026thinsp;0.295, SE\u0026thinsp;=\u0026thinsp;0.182, OR\u0026thinsp;=\u0026thinsp;1.343, 95% CI [0.938, 1.922], p\u0026thinsp;=\u0026thinsp;0.106) (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e and Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eIn the final model (M₃), the pronator teres thickness was included as a third predictor. This model significantly enhanced the overall fit (Δχ\u0026sup2;(\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e)\u0026thinsp;=\u0026thinsp;4.147, p\u0026thinsp;=\u0026thinsp;0.042) and accounted for 34.9% of the variance (Nagelkerke R\u0026sup2; = 0.349). FDP thickness remained a strong predictor (B\u0026thinsp;=\u0026thinsp;0.402, SE\u0026thinsp;=\u0026thinsp;0.113, OR\u0026thinsp;=\u0026thinsp;1.495, 95% CI [1.203, 1.857], p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), while the median nerve thickness also became more influential (B\u0026thinsp;=\u0026thinsp;0.418, SE\u0026thinsp;=\u0026thinsp;0.217, OR\u0026thinsp;=\u0026thinsp;1.519, 95% CI [0.994, 2.324], p\u0026thinsp;=\u0026thinsp;0.054). Interestingly, the thickness of the pronator teres showed a negative association with the likelihood of being a sport climber (B = -0.305, SE\u0026thinsp;=\u0026thinsp;0.158, OR\u0026thinsp;=\u0026thinsp;0.737, 95% CI [0.538, 1.008], p\u0026thinsp;=\u0026thinsp;0.054) (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e and Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eOverall, the final model demonstrated a good fit, with a McFadden R\u0026sup2; of 0.227, a Nagelkerke R\u0026sup2; of 0.349, and a Tjur R\u0026sup2; of 0.289 (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). The model's predictive performance was further supported by the ROC analysis, yielding an area under the curve (AUC) of 0.814, indicating excellent discriminative ability. The model achieved an accuracy of 82.0%, a sensitivity of 58.8%, and a specificity of 93.9%. (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e)\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eMulticollinearity diagnostics indicated acceptable tolerance values for all included predictors, suggesting no substantial multicollinearity in the model. Specifically, the Flexor Digitorum Profundus had a tolerance of 0.747 (VIF\u0026thinsp;=\u0026thinsp;1.340), the Median Nerve showed a tolerance of 0.786 (VIF\u0026thinsp;=\u0026thinsp;1.273), and the Pronator Teres presented a tolerance of 0.671 (VIF\u0026thinsp;=\u0026thinsp;1.491). Residual diagnostics confirmed the absence of significant autocorrelation (Durbin-Watson\u0026thinsp;=\u0026thinsp;2.354).\u003c/p\u003e\u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis study aimed to identify sex-related differences in forearm muscle and nerve morphology among climbers and to explore potential anatomical predictors of climbing discipline. Significant differences in muscle thickness were observed between sexes for all muscles assessed brachioradialis, pronator teres, flexor digitorum superficialis, flexor digitorum profundus and pronator quadratus, except for the radial nerve. These findings suggest that sex plays a central role in anatomical adaptation to climbing stress, while neither limb dominance nor the interaction between sex and dominance exerted statistically significant effects.\u003c/p\u003e\u003cp\u003eThe greater muscle thickness observed in male climbers is consistent with previous studies linking male sex to increased hypertrophy, attributed to hormonal factors specifically circulating testosterone levels that are 15\u0026ndash;20 times higher than those of females from puberty onward and to higher training loads in men, which facilitate greater muscle gains (\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eA systematic review indicated a significant association between male sex and a higher risk of overuse injuries, which may be linked to men achieving higher climbing grades and accumulating greater experience over time (\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e). In contrast, female climbers exhibited a higher rate of traumatic injuries. Although no studies to date have directly linked forearm muscle thickness to sex, the greater muscle thickness observed in male participants in this study could be partially explained by their significantly higher values in height, weight, and BMI compared to females factors that may influence overall muscular development.\u003c/p\u003e\u003cp\u003eA greater median nerve thickness was also observed in male climbers, in contrast to the radial nerve, which showed no sex-related differences. This disparity may be explained by the anatomical pathway and mechanical compression points each nerve encounters during climbing. Specifically, the median nerve passes through the carpal tunnel and is subjected to compressive forces during repetitive gripping maneuvers, which may induce adaptive thickening in response to chronic mechanical stress (\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eThe MANOVA analysis confirmed that sex was the primary determinant of morphological differences, with no significant effects observed for limb dominance or its interaction with sex. This suggests that, although climbing is a bilateral activity, anatomical adaptations are more strongly driven by sex-related physiological factors than by preferential use of one side of the body.\u003c/p\u003e\u003cp\u003eRegarding climbing style, the hierarchical logistic regression analysis identified the flexor digitorum profundus thickness as the strongest anatomical predictor. Climbers with greater FDP thickness were more likely to specialize in sport climbing compared to bouldering. This relationship aligns with the biomechanical demands of sport climbing, which is characterized by longer routes and endurance requirements involving sustained isometric contractions of the deep finger flexors (\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e). Increased FDP development may reflect a functional adaptation to prolonged gripping efforts.\u003c/p\u003e\u003cp\u003eJonathan Leung identified in his study that climbing injuries are primarily due to overuse and most frequently affect the upper limbs. Moreover, he was able to differentiate injury prevalence based on climbing discipline (\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e). Boulder climbers showed a higher incidence of traumatic injuries, particularly in the ankles and knees, as a result of falls from height. In contrast, sport climbing was associated predominantly with overuse injuries, especially affecting the fingers, elbows, and shoulders, due to repetitive movements, finger overload, and excessive use of maximal grip force.\u003c/p\u003e\u003cp\u003eThe inclusion of median nerve thickness in the predictive model moderately increased its explanatory power, suggesting a possible role of neural adaptations or stress-induced changes in differentiating climbing disciplines. Although the effect did not reach conventional levels of statistical significance (p\u0026thinsp;=\u0026thinsp;0.054), the observed trend justifies further exploration in future studies involving larger samples or climbers at higher competitive levels. This is consistent with previous findings indicating that chronic mechanical compression, such as that experienced during repetitive gripping, can induce measurable nerve thickening, especially in peripheral nerves exposed to repetitive strain (\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eSimilarly, pronator teres thickness showed a negative association with sport climbing, which may reflect greater development in boulder climbers. This population often performs explosive, high-intensity upper limb movements requiring powerful forearm pronation and elbow stabilization, movements in which the pronator teres plays a key functional role (\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eThe final regression model demonstrated high classification accuracy (82%), excellent discriminative ability (AUC\u0026thinsp;=\u0026thinsp;0.814), and no issues with multicollinearity or autocorrelation, reinforcing the robustness of the findings. Collectively, these results provide preliminary evidence that ultrasound-measured anatomical variables particularly the thickness of the flexor digitorum profundus and the median nerve could serve as non-invasive indicators of climbing specialization.\u003c/p\u003e\u003cdiv id=\"Sec18\" class=\"Section2\"\u003e\u003ch2\u003eLimitations\u003c/h2\u003e\u003cp\u003eThis study presents important methodological considerations that should be considered when interpreting the results. While musculoskeletal ultrasound (USI) provided a reliable and non-invasive method for assessing forearm muscle and nerve morphology, it did not include direct measurements of muscle strength or functional capacity. Therefore, the relationship between anatomical adaptations and climbing performance remains partially unexplored. Future research should integrate objective assessments of grip strength or climbing-specific tasks to clarify these associations.\u003c/p\u003e\u003cp\u003eAnother limitation lies in the static nature of ultrasound imaging. Measurements were taken under resting conditions, which may not fully reflect the functional demands imposed during climbing. The integration of surface electromyography (sEMG) in future protocols could offer additional insight into neuromuscular activation patterns under load or during sport-specific gestures.\u003c/p\u003e\u003cp\u003eFinally, although climbers were grouped based on their predominant climbing discipline (bouldering vs. sport climbing), the degree of cross-participation between styles was not systematically recorded. This overlap may have influenced the morphological differences observed between groups.\u003c/p\u003e\u003c/div\u003e"},{"header":"Conclusions","content":"\u003cp\u003eThe findings of this study revealed significant sex-based differences in forearm muscle and median nerve thickness among climbers. Male participants exhibited greater thickness across all assessed muscles including the brachioradialis, pronator teres, flexor digitorum superficialis, flexor digitorum profundus and pronator quadratus as well as the median nerve. In contrast, no significant differences were observed for the radial nerve.\u003c/p\u003e\u003cp\u003eNo effects were found related to limb dominance, suggesting that anatomical adaptations in climbers occur bilaterally, regardless of preferential arm use. This supports the notion that climbing imposes symmetrical demands on the upper limbs.\u003c/p\u003e\u003cp\u003eRegarding climbing discipline, the FDP thickness emerged as the most consistent anatomical predictor of sport climbing specialization. Greater FDP thickness was associated with a higher likelihood of practicing lead climbing over bouldering, and this association remained significant after controlling for other morphological variables. Median nerve thickness also showed a positive trend toward sport climbing, while pronator teres thickness was inversely associated, potentially indicating different muscular adaptation patterns in bouldering athletes.\u003c/p\u003e\u003cp\u003eThese results underscore the value of ultrasound-based assessments in identifying structural adaptations linked to sex and climbing style, which may inform future approaches in training, screening, and injury prevention for climbers.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\n\u003cp\u003eConceptualization: H.C.-B., D.L.-L., C.R.-M.Methodology: H.C.-B., \u0026Aacute;.G.-F., M.G.-M., D.M.-M., G.J.-C.Formal analysis: H.C.-B., M.B.-A., M.E.-R., D.J.-P.Investigation / Data collection: M.B.-A., M.E.-R., D.J.-P., \u0026Aacute;.G.-F., M.G.-M., D.M.-M., G.J.-C.Visualization (figures, tables): H.C.-B., M.B.-A., \u0026Aacute;.G.-F.Writing \u0026ndash; original draft: H.C.-B.Writing \u0026ndash; review \u0026amp; editing: M.B.-A., M.E.-R., D.J.-P., \u0026Aacute;.G.-F., M.G.-M., D.M.-M., G.J.-C., D.L.-L., C.R.-M.Supervision: D.L.-L., C.R.-M.Project administration: H.C.-B., C.R.-M.All authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData Availability\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets generated and/or analysed during the current study are not publicly available due to privacy and ethical restrictions but are available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflicts of Interest and Source of Funding:\u0026nbsp;\u003c/strong\u003eThere are no conflicts of interest or Source of Funding.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eFaggian, S. et al. 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Reliability and Validity of Functional Grip Strength Measures Across Holds and Body Positions in Climbers: Associations With Skill and Climbing Performance. \u003cem\u003eRes. Q. Exerc. Sport\u003c/em\u003e. \u003cb\u003e94\u003c/b\u003e (3), 627\u0026ndash;637 (2023).\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eCartwright, M. S. et al. Ultrasound for carpal tunnel syndrome screening in manual laborers. \u003cem\u003eMuscle Nerve\u003c/em\u003e. \u003cb\u003e48\u003c/b\u003e (1), 127\u0026ndash;131. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1002/mus.23735\u003c/span\u003e\u003cspan address=\"10.1002/mus.23735\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2013). Epub 2013 May 6.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eBal\u0026aacute;š, J. et al. Active range of motion of the shoulder joint in sport climbers. \u003cem\u003eInt. J. Sports Med.\u003c/em\u003e \u003cb\u003e33\u003c/b\u003e (9), 766\u0026ndash;770. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1055/s-0032-1301882\u003c/span\u003e\u003cspan address=\"10.1055/s-0032-1301882\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2012).\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-7530539/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7530539/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground\u003c/strong\u003e: Sport climbing is a physically demanding discipline that places repetitive mechanical load on the upper limbs, potentially leading to morphological adaptations or overuse injuries. Despite this, musculoskeletal ultrasound (USI) has been underutilized in climbing research. This study aims to investigate sex-related differences in forearm muscle and nerve morphology in climbers and to determine whether these structural features can predict climbing specialization (bouldering vs. sport climbing).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods\u003c/strong\u003e: A cross-sectional study was conducted with 50 recreational climbers (25 males, 25 females). Ultrasound imaging was used to assess the thickness of key forearm muscles (brachioradialis, pronator teres, flexor digitorum superficialis/profundus, pronator quadratus) and the median and radial nerves.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults:\u003c/strong\u003e Significant sex differences were observed for all muscles and the median nerve (p \u0026lt; 0.001), with males exhibiting greater thickness. No differences were found for the radial nerve or between dominant and non-dominant limbs. Logistic regression identified flexor digitorum profundus (FDP) thickness as the strongest anatomical predictor of sport climbing, with each 1 mm increase in FDP thickness raising the odds of being a sport climber by 48.2%. The final model, including FDP, median nerve, and pronator teres thickness, showed excellent discriminative ability (AUC = 0.814, accuracy = 82%).\u003cstrong\u003e Conclusions: \u003c/strong\u003eUltrasound-based assessments revealed robust sex-related morphological differences in climbers’ forearm musculature and median nerve. Greater FDP thickness is strongly associated with sport climbing specialization. These findings suggest that USI may be a valuable tool for profiling climbers, guiding training programs, and informing injury prevention strategies.\u003c/p\u003e","manuscriptTitle":"Sex-based forearm morphology in climbers: an ultrasound study and it´s predictive value for climbing style","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-10-08 07:23:28","doi":"10.21203/rs.3.rs-7530539/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-03-13T05:56:41+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-03-11T15:17:45+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"121450699841822875054461453953283220780","date":"2026-02-19T11:15:42+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"5808969190078560204090050969910040082","date":"2025-11-27T16:37:39+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-11-05T20:43:23+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"190049666229043422988615863100674761120","date":"2025-10-17T05:27:59+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"44047409445708741740581792831277466952","date":"2025-09-26T18:59:39+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-09-24T18:55:16+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-09-24T18:53:25+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-09-24T05:57:03+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-09-11T08:21:04+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2025-09-11T08:14:54+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"9f460f53-c719-454a-baec-7ae3bb14cf84","owner":[],"postedDate":"October 8th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"in-revision","subjectAreas":[{"id":55857116,"name":"Health sciences/Anatomy"},{"id":55857117,"name":"Health sciences/Health care"}],"tags":[],"updatedAt":"2026-05-19T07:25:18+00:00","versionOfRecord":[],"versionCreatedAt":"2025-10-08 07:23:28","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7530539","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7530539","identity":"rs-7530539","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}