Comparison of the effects of different warm-up protocols on anabolic-catabolic balance, fatigue, physical readiness, and technical skill measures: Study protocol for a randomized parallel study in young male soccer players

Comparison of the effects of different warm-up protocols on anabolic-catabolic balance, fatigue, physical readiness, and technical skill measures: Study protocol for a randomized parallel study in young male soccer players | 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 Method Article Comparison of the effects of different warm-up protocols on anabolic-catabolic balance, fatigue, physical readiness, and technical skill measures: Study protocol for a randomized parallel study in young male soccer players Hamzeh Zarei, Khosro Jalali Dehkordi, Farzaneh Taghian, Filipe Manuel Clemente This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7105813/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Introduction Warm-up routines are essential for optimizing soccer players’ performance, yet their specific effects on adolescents, with unique hormonal and physiological characteristics, remain underexplored. This study aims to identify effective warm-up strategies to enhance physical fitness, technical skills, and fatigue management in youth soccer players under 15 years old. Methods and Analysis The study involves 72 semi-elite male soccer players, randomly assigned to one of six groups: five experimental warm-up protocols (Integrated, Analytical, Small-Sided Games [SSG], Analytical + Dynamic, SSG + Integrated) and one control group performing a standard dynamic warm-up. Participants will complete an eight-week training program with warm-up routines applied for 20 minutes at the start of training sessions, three times per week (24 sessions total). Outcomes assessed include physical performance (endurance, explosive power, sprint speed, and agility), technical skills (dribbling and passing accuracy), physiological markers (testosterone, cortisol, and LDH levels during simulated matches), and fatigue indicators (neuromuscular, musculoskeletal, and metabolic measures). Data will be collected at baseline, post-intervention, and follow-up. Ethics and Dissemination This project has been approved by the Research Ethics Committee of Islamic Azad University, Isfahan (Khorasgan) Branch (IR.IAU.KHUISF.REC.1403.419). Findings will be disseminated through peer-reviewed publications and presentations at relevant academic conferences, providing practical recommendations for coaches and trainers to optimize warm-up routines for adolescent soccer players. Sports Medicine and Kinesiology Warmup Exercise Testosterone/Cortisol Ratio Fatigue Athletic Performance Soccer Randomized study Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 WHAT IS ALREADY KNOWN ON THIS TOPIC ⇒ Warm-up routines are essential for enhancing soccer performance, with dynamic protocols improving physical readiness, skill execution, and injury prevention. ⇒ Hormonal markers like testosterone and cortisol are sensitive indicators of training stress and performance readiness in adolescent athletes. ⇒ Structured warm-ups can optimize neuromuscular and metabolic efficiency while reducing fatigue accumulation. WHAT THIS STUDY ADDS ⇒ This study is the first to compare the acute and chronic effects of six distinct warm-up protocols on physical, technical, and hormonal adaptations in U-15 soccer players . ⇒ It integrates biochemical markers (cortisol, testosterone, LDH) with performance metrics to identify the most effective warm-up strategies for adolescent athletes . ⇒ Findings will provide evidence-based recommendations for designing warm-ups tailored to the unique physiological needs of youth soccer players . HOW THIS STUDY AFFECTS RESEARCH, PRACTICE, OR POLICY ⇒ Results will guide coaches in implementing warm-up protocols that enhance performance and reduce injury risks in adolescent athletes . ⇒ Hormonal and fatigue-related insights may influence training load management and recovery strategies in youth sports . ⇒ This research could shape future policies on warm-up practices in football academies, promoting long-term athletic development . INTRODUCTION Soccer performance depends on many things. For young players, skills like dribbling and passing matter most, while for professionals, physical strengths such as jumping, power, and endurance are key. Efficient movement might also be important, though it hasn’t been fully explored yet. (1) . Warm-up is important for soccer performance, with research showing its importance in enhancing physical condition and performance (2) . Dynamic stretching and post activation potentiation exercises have been found to improve acute performance by 3.46% and 4.21%, respectively (3) . The FIFA 11+ warm-up program has shown significant increases in strength, jump, speed, and explosive performances. Dynamic stretching as part of a warm-up leads to superior performance in vertical jump, 20-m sprint, and agility tests compared to static stretching (2) . Biochemical parameters play an important role in monitoring the athlete’s responses to the imposed training loads since they give abundant information about how athletes evolve (4) . Hormonal monitoring helps optimize training loads and prevent burnout and injuries in teen soccer players, in this regard, examining the anabolic /catabolic (A/C) balance is of particular importance (5) . The testosterone/cortisol (T/C) ratio and combination of them may be useful to measure the balance between A/C and to indicate the level of wellness/fatigue as a means of avoiding overtraining and overreaching (6) . In fact, testosterone and cortisol have been related with that ability to perform soccer skills at high intensity and recovery capacity (7) . these hormones play a role in catabolic and anabolic processes and are frequently used in studies as training stress marker (8) . These parameters can be estimated for evaluating the degree of muscle damage, hydration/dehydration, inflammation, oxidative damage, and other factors that facilitate the evaluation of the response of the athlete’s body to the different exercise or training loads being carried out (9) . Emerging research underscores the critical role of hormonal monitoring in optimizing athletic development, particularly during puberty when anabolic-catabolic balance significantly influences training adaptations. Recent findings demonstrate that serum cortisol and testosterone levels in adolescent athletes serve as sensitive biomarkers of training stress, with disproportionate cortisol elevations (>20% above baseline) correlating with impaired neuromuscular performance (r = -0.68, p < 0.01) and increased injury risk (10) . This endocrine profiling proves especially valuable when assessing warm-up efficacy, as transient hormonal fluctuations during preparatory exercise may dictate subsequent match performance. Lactate dehydrogenase (LDH) has emerged as a key indicator of metabolic strain, with post-activity levels reflecting the cumulative cellular stress of athletic performance. A 2025 longitudinal study revealed that adolescent soccer players exhibiting endurance performances are positively affected after high intensity warm-up phases that increase the REP by athletes in the warm-up phase (11) . Warm-up protocols, while transient in duration, critically prime neuromuscular efficiency, hormonal regulation, and metabolic readiness in soccer players. Emerging evidence highlights that structured warm-ups enhance post-activation potentiation (PAP), optimizing motor unit recruitment and force transmission during subsequent activity (12) . This neuromuscular priming is further linked to transient hormonal shifts, including cortisol suppression and testosterone elevation, which modulate anabolic-catabolic balance (A/C) even in the absence of sustained metabolic demand (13) . Additionally, warm-up-induced increases in muscle temperature and oxygen kinetics improve movement economy, reducing fatigue accumulation during high-intensity efforts (14) . In youth athletes, whose hormonal profiles and neuromuscular plasticity are distinct from adults, tailored warm-ups may amplify skill acquisition while mitigating injury risks via enhanced proprioceptive feedback. Thus, analyzing warm-up strategies provides actionable insights into acute physiological adaptations that indirectly influence long-term performance trajectories (15) . While previous investigations have explored warm-up physiological effects, few have integrated hormonal, biochemical, and performance measures in adolescent populations. In a recent review, the potential physiological benefits of stretching exercises and sports performance, key differences, and comparisons with static exercises are considered as critical components of a multifaceted approach (16) . while Hackney (17) linked a conceptual framework of endocrine reactivity to the physical Stress of exercise, Dalle, S., et al. state that Anabolic/catabolic balance is crucial for athletes, especially under energy restriction or intense training (18) . A 2022 study tracked hormonal responses in youth soccer players over a season, observing significant changes in testosterone, cortisol, and growth hormone levels due to training intensity (19) . This study uniquely synthesizes these domains through a randomized comparison of six evidence-based protocols, addressing critical gaps in youth-specific warm-up guidelines. This study aims to determine the acute and longitudinal effects of five structured warm-up protocols (Integrated, Analytical, SSG, and combined Analytical+ Dynamic/SSG+ Integrated) versus a dynamic warm-up control on sport-specific adaptations in U-15 soccer players. The primary objective is to identify which protocol(s) most effectively enhance physical performance (aerobic endurance, anaerobic power, explosive strength, sprint, agility), technical execution (dribbling, passing, composite skills), and physiological resilience (anabolic-catabolic balance via cortisol/testosterone ratios, LDH-mediated metabolic stress). A secondary objective is to quantify fatigue dynamics (neuromuscular, musculoskeletal, metabolic) across four timepoints (T1-T4) to assess recovery and sustainability of adaptations. By prioritizing adolescent-specific hormonal and neuromuscular plasticity, this protocol seeks to establish a hierarchy of warm-up efficacy for optimizing performance readiness while reducing injury susceptibility in youth athletes. Research question, aim and objectives The research question for the randomized parallel study is: What are the effects of different warm-up protocols on anabolic-catabolic balance, fatigue, physical readiness, and technical skill performance in male youth soccer players? The study will aim to compare the effects of different warm-up protocols on anabolic-catabolic balance, fatigue, physical readiness, and technical skill performance among semi-elite male youth soccer players (under 15 years), using validated physiological and performance markers. To answer the research question, we have set out to meet the following objectives: What are the acute and chronic effects of different warm-up protocols on serum cortisol and testosterone levels in male youth soccer players ? What are the acute and chronic effects of different warm-up protocols on blood lactate levels in male youth soccer players ? What are the acute and chronic effects of different warm-up protocols on fatigue measures in male youth soccer players ? Is there an association between hormonal levels (cortisol, testosterone, cortisol/testosterone ratio), lactate and external training load in male youth soccer players ? What are the effects of different warm-up protocols on aerobic endurance, explosive power, peak sprint speed, anaerobic power, dribbling speed, passing accuracy, and technical skills (F-MARK) in male youth soccer players? METHODS Study design The study will employ a randomized parallel design to collect quantitative data on physical, physiological, and technical performance indicators in U-15 semi-professional male soccer players. Participants will be recruited from the Nesf-e-Jahan Soccer team, which competes in the first division of the grassroots football league in Isfahan province. Prior to participation, written consent will be obtained from the club and the players’ parents. Context data collection will be carried out over an eight-week period, from June 23, 2024, to August 15, 2024. The data will be gathered on odd days of the week (Sunday, Tuesday, and Thursday) immediately after the pre-season training sessions of the 2024-2025 grassroots football leagues in Isfahan Province . Study population This study is a randomized parallel study design in U-15 male soccer players. This age group has been selected because it is underrepresented in studies implemented In the A/C balance and fatigue with the implementation of different warm-up protocols and examining physical fitness and skill factors in a group of adolescents context (20) . Recruitment Seventy-two U-15 players from a first-division Iranian soccer club (Isfahan) will be randomly allocated to six groups: SSG, Analytical, Integrated, SSG+ Integrated, Analytical+ Dynamic, and Dynamic (control). Ethical protocols include parental/player informed consent after club approval and detailed study briefings (Figure 1&2). Randomization Club principal, as a person independent of the study, will conceal participant allocation by shaking a bag with all 72 players (3 teams), before baseline testing. Groups will be randomized such that 5 selection from each principal's try will be allocated to the intervention condition and the other one to the control condition. Using this approach, each group will have an equal chance of being allocated to the intervention condition, while maintaining an appropriate balance of grades across the two conditions. Inclusion/exclusion criteria Inclusion criteria will require players to attend all warm-up sessions and remain healthy and injury-free throughout the study. Eligible participants will have no history of nutritional supplement use, will have completed at least three years of consistent training and competition, and will not have any diagnosed cardiovascular or musculoskeletal conditions. Players will be excluded if they miss more than 20% of training sessions, sustain injuries resulting in absences over three days, or show a decline of 15% or more in two baseline performance tests. Sample size Power analysis G*Power 3.1.9.4 accounted for the study's 6-group repeated-measures design with multiple outcomes. Estimating a moderate multivariate effect size (η² = 0.15) based on prior warm-up literature(14), with α=0.05, power=0.80, and 5 dependent variables, the required sample was 66 (11/group). We increased this to 72 (12/group) to accommodate potential attrition and ensure adequate power for univariate follow-ups to significant results. Intervention and control groups Over 8 weeks, four U-15 coaches will administer five different warm-up protocols in the first 20 minutes of each session, three times weekly. The 12-player control group will perform a 16-exercise dynamic warm-up (DWU). All participants will complete physical, skill assessments, and provide blood samples for biochemical analysis (21) . Table 1 shows the dynamic warm-up protocol (control group). Table 1. Dynamic warm-up protocol Taylor et al (21) N Exercise Description 1 High Knee Alternating knee raises synchronized with arm motion. 3 × 20m. 2 Butt Flicks Controlled flicking motion of heels toward glutes. 3 × 20m (15–20 reps). 3 Carioca Lateral crossover steps over 3 × 20m each side. 4 Dynamic Hamstring Swings Controlled leg swings to full range of motion. 3 × 10 reps per leg. 5 Dynamic Groin Swings Controlled leg swings targeting groin muscles. 3 × 10 reps per leg. 6 Arm Swings (Forward/Back) Controlled arm swings in both directions. 3 × 10 reps per direction. 7 Faster High Knee High-speed alternating knee raises over 4 × 10m. 8 Swerving Controlled swerving motion over 2 × 30m at 70% max pace. 9 Side Stepping Lateral steps over 2 × 30m at 80% max pace. 10 Spiderman Walks Controlled walking motion with wide strides. 1 × 20m (10 reps per side). 11 Sideways Low Squat Walks Squat walk in a sideways motion × 10 steps each direction. 12 Upper Body Rotations Controlled rotations of the upper body × 10 reps per direction. 13 Vertical Jump Explosive jumps × 5 reps (progressive effort 60% → 90%). 14 Run Through Sprint intervals: 2 × 20m (70%), 2 × 20m (80%), 1 × 20m (90%). 15 Countermovement Jump + 5m Sprint Explosive jump followed by 5m sprint (90% × 2, 95% × 1). 16 Sprint + Countermovement Jump Sprint for 5m followed by explosive jump × 2 sets. Warm-Up Protocols This study involves 24 warm-up sessions over 8 weeks, with players warming up for 20 minutes at the start of training, three times a week. Before and after the program, players complete fitness and skill tests, and provide blood samples both before and after a simulated soccer match. All sessions take place on the same type of field and in similar weather, with nutrition and sleep managed by parents to keep conditions fair. Other training stays the same, so only the warm-up routines are different. Warm-ups are held between 5 and 7 pm, and players avoid hard exercise two days before the initial tests . (figures 4&5) show detail the timeline, session sequencing, and intervals between assessments. Small-Sided Games Warm-Up (SSGW) The standardized SSG warm-up protocol consisted of three progressive components: (1) a 5-minute aerobic jogging phase, (2) 5 minutes of sport-specific dynamic movements including 20-meter shuttle drills, and (3) a 6-minute technical activation phase using 5v1 rondo drills in a 7×7meter grid with 1-minute defender rotations. This 20-minute protocol was adapted from established small-sided game warm-up methodologies (22) to optimize physiological and technical preparation while maintaining sport-specificity (Figure.3a). Integrated Warm-Up (IWU) The experimental IWU protocol will employ 2×10-minute small-sided game (SSG) played on a 20×28 m pitch with 1×1 m mini-goals and a standard size 5 Mikasa match ball (Figure. 3b). A qualified club physical trainer will supervise all sessions, maintaining game intensity through immediate ball replacement when play is interrupted. To eliminate external influences on exercise intensity, no verbal encouragement will be provided during gameplay. The modified ruleset will include: (1) elimination of throw-ins and corner kicks - with all restarts occurring from midfield, (2) unlimited player contacts, and (3) requirement for complete team advancement into the attacking half for goal validation. This protocol design follows established SSG implementation frameworks used in recent football training studies (23) . SSG Warm-up (SSGWU) + Integrated Warm-up (IWU) Sequential 10-minute phases of SSGW and IWU will be integrated to synergize their physiological and technical benefits while preserving the integrity of their original structures (Figure 3c). Analytical warm-up (AWP) Based on Coledam et al (24) ., it incorporates 12 controlled dynamic drills to refine motor skills and improve coordination (Table2). Table 2. Analytical warm-up protocol. Coledam et al (24) N Exercise Description 1 High knee skipping The player jogs while lifting their knees toward the chest. Support is on the forefoot, with alternating arm movements for balance. Approximately 12-15 knee lifts per leg every 10 seconds (around 180 total repetitions). 2 Dynamic hamstrings swing The player jogs with alternating arm movements, lifting one extended leg forward before returning to the starting position and repeating with the other leg. 10-12 swings per leg every 10 seconds (around 120 total swings) 3 Squat and run The player performs a squat, immediately followed by a short burst of running. 8-10 squat-run cycles (depending on intensity). 4 Inward hip circumduction The player jogs with alternating arm movements, performing an inward circular motion with one hip before returning to the starting position and repeating with the other leg. 10-12 inward hip rotations per leg every 10 seconds (around 120 total rotations). 5 Outward hip circumduction The player jogs with alternating arm movements, performing an outward circular motion with one hip before returning to the starting position and repeating with the other leg. 10-12 outward hip rotations per leg every 10 seconds (around 120 total rotations). 6 Lateral side to side jog with left leg The player moves laterally to the left, leading with the left leg. Feet do not cross, and arms stay open for balance. 8-10 lateral movements to the left and back in each 10-second interval (around 80-100 total). 7 Lateral side to side with right leg The player moves laterally to the right, leading with the right leg. Feet do not cross, and arms stay open for balance. 8-10 lateral movements to the right and back in each 10-second interval (around 80-100 total). 8 Lunge walk The player walks forward, performing alternating lunges with each leg. The trunk stays upright, and the arms swing naturally for balance. 8-10 lunges per leg every 10 seconds (around 80-100 total lunges). 9 Butt flicks The player quickly moves the heels toward the gluteus, while the trunk remains straight, with arms oscillation. 2 sets of 20 seconds 10 Backward running The player performs a reverse running, so that he travels in the direction his back is facing rather than his front. 2 sets of 20 seconds 11 Fast skipping The player performs a knee raise while advancing. Frequency and range of motion should be considered. The trunk should remain slightly tilted, alternating the arms. 2 sets of 20 seconds 12 Backward running with turn and sprint The player performs a half-reverse run, then turns and performs a frontal sprint. 2 sets of 20 seconds Dynamic warm-up (DWP)+ Analytical warm-up (AWP) This protocol will integrate the two aforementioned warm-up methodologies, beginning with a 10-minute dynamic phase followed by a 10-minute analytical phase. To preserve scientific rigor, every segment will adhere precisely to the original protocols’ structure and execution standards. The synergistic alignment of these methods is projected to amplify the study’s performance outcomes, leveraging their complementary physiological and neuromuscular benefits. Internal training Load assessment Heart rate monitor and motion analysis system Players’ heart rates will be tracked in real time with the Polar H10, recording data every second and measuring distance covered. The device connects easily via Bluetooth and ANT+, sending data to Polar Team Pro software, which can monitor up to 60 players at once. This system will help coaches assess training intensity, sprint counts, and recovery status, making it easier to balance workload and rest. To ensure accurate training zones and intensity, the Edwards TRIMP method will be used, which calculates training load by weighing the time spent in different heart rate zones. (25) . The rate of perceived exertion (RPE) RPE will be used to assess subjective effort immediately following each warm-up protocol. A standardized question ('How was your exercise experience?') will be administered to maintain consistency in data collection (26) . 2.10. External training Load assessment (Functional tests) The execution sequence and temporal spacing of functional tests are critical determinants of data validity in sports science research, particularly when assessing adolescent athletes with evolving physiological and neuromuscular capacities. This study implements a rigorously structured testing hierarchy informed by established principles of fatigue mitigation, test-retest reliability, and ecological validity. To preserve test integrity, assessments are sequenced according to their metabolic demand and neuromuscular fatigue induction potential, with high-intensity anaerobic tests (e.g., RAST, 30m sprints) separated by ≥72-hour recovery periods to minimize residual fatigue effects (27) . Aerobic capacity evaluations (Yo-Yo IR1) precede anaerobic power tests to avoid glycogen depletion biases, while skill assessments (RST, LSPT) are conducted after physical testing to replicate match conditions where technical execution occurs under physiological strain (28) . The Yo-Yo Intermittent Endurance Test (28) measures aerobic fitness by running 20m shuttles at increasing speeds until exhaustion. The RAST (29) assesses anaerobic power with six 35m sprints and short rests. The CoD test. (30) checks agility by sprinting, turning sharply, and sprinting back. The Sprint Peak Test (31) measures explosive acceleration and top speed over 30m. The CMJ test (32) gauges lower-body power through a vertical jump. The Standing Long Jump (33) measures horizontal explosive strength. The Hop Left and Right Test (34) assesses endurance, strength, and stability by hopping side to side on one leg for 30 seconds . External training Load assessment (Skill tests) Dribbling speed test in soccer The Ronaldo Speed Test (RST) assesses dribbling speed via timed cone navigation and goal scoring, validated through sequential accuracy. Standardized warm-up minimizes bias, ensuring reliable data (35) . Passing skill test The Loughborough Soccer Passing Test (LSPT) will be used to assess this skill. LSPT is a reliable and valid test, which assesses the multifaceted aspects of soccer skill including passing, dribbling, control, and decision making (36) . F-MARK Skill Tests The F-MARC test battery-a scientifically validated 2.5-hour protocol-precisely evaluates soccer-specific physical capacities by simulating match demands, enabling coaches to benchmark players against peer norms and quantify training adaptations. For enhanced efficiency, this study will implement a focused selection of technical-tactical assessments adapted from Balsom's handbook (37) ,and Rosch's study (38) delivering actionable insights while maintaining rigorous sport-specific evaluation standards. Skills that will be reviewed include: juggling (foot); juggling (body); long passing; short passing; shooting (dead ball); shooting from a pass (foot) and heading. Biochemical analysis (Blood serum Testosterone/Cortisol/ lactate dehydrogenase (LDH) collection and analysis Serum lactate dehydrogenase (LDH) will be measured spectrophotometrically (Iric-kit/Alpha-Classic); cortisol/testosterone via semi-automatic ELISA (Monoband-method/State fax) at Farabi Laboratory, Isfahan, by expert staff. Considerations This study examines 72 adolescent male soccer players from three competitively matched teams (Nesf-e-Jahan Club, Isfahan, Iran). Anthropometrics were assessed at baseline, mid-/post-intervention (4/8 weeks). Accredited coaches supervised HR-monitored training; stable diets minimized confounders. Ethical rigor included parental/institutional consent and pre-season protocols (39) . Research implementation stages This study schedules functional and biochemical tests in separate weeks to ensure accurate, reliable, and physiologically sound results (Table 3). By spacing out different tests, the protocol reduces fatigue and ensures accurate results for both performance and hormone measures. This approach follows sports science best practices, respects young athletes’ real-world demands, and uses clear visual diagrams to document the testing schedule and maintain the study’s reliability. (Figure 4) systematically presents the administration timeline for all functional and sport-specific evaluations, providing clear reference points for performance measurement intervals. (Figure 5) offers detailed visualization of SMS (40) and its associated biochemical sampling schedule, including baseline (T1), acute response (T2), and follow-up (T3, T4) assessment points. These figures clearly show the study’s schedule, helping readers understand the timing of tests and samples. By following standard formats, they also make it easier for others to repeat the study accurately . Table 3. Research Methodology Groups Pre Test independent variable dependent variable Post Test DWU (Control) T2 و T1 X1 D1, D2, D3, D4, D5, D6, D7, D8, D9, D10 T4 و T3 SSGW T2 و T1 X2 D1, D2, D3, D4, D5, D6, D7, D8, D9, D10 T4 و T3 AWU T2 و T1 X3 D1, D2, D3, D4, D5, D6, D7, D8, D9, D10 T4 و T3 IWU T2 و T1 X4 D1, D2, D3, D4, D5, D6, D7, D8, D9, D10 T4 و T3 DWU+AWU T2 و T1 X5 D1, D2, D3, D4, D5, D6, D7, D8, D9, D10 T4 و T3 SSGW+IWU T2 و T1 X6 D1, D2, D3, D4, D5, D6, D7, D8, D9, D10 T4 و T3 T1 and T2: measurement of primary variables T3 and T4: measuring the variables after 8 weeks (Follow-up) X1, X2, X3, X4, X5, X6: Warm-up protocols in six groups D1: Internal Training load D2: External Training load D3: Serum cortisol level D4: Testosterone serum level D5: Lactate level D6: Cortisol/testosterone ratio D7: Fatigue indicators D8: Heart rate fluctuations (RHR, MHR, HR reserve, THR) D9: performance factors D10: Skill factors Statistical analyses Data analysis will be employed SPSS 27.0, with six groups (control + five interventions; n=12 each). Mixed-design ANOVA evaluates between/within-group differences, following Shapiro-Wilk (normality), Levene (variance), and Mauchly (sphericity) tests. Bonferroni-adjusted comparisons, ANCOVA, Pearson/regression models, and intention-to-treat principles with MICE imputation ensure rigor. Effect sizes (η², Cohen’s d) and 95% CIs are reported; independent statisticians maintain objectivity. Discussion Warm-ups are essential in youth soccer, as they enhance performance, reduce injury risk, and help manage fatigue (4) . Neuromuscular training integrated into regular soccer warm-up sessions has shown significant benefits in improving dynamic balance, horizontal jump, and change-of-direction performances, along with boosting self-confidence and reducing cognitive anxiety in highly-trained pubertal soccer players (4, 5) . Additionally, structured dynamic warm-ups that combine injury prevention and performance strategies have been reported to lower injury incidence and enhance performance in sub-elite youth players over mid-to-long-term applications (2, 5) Dynamic warm-ups have consistently demonstrated improvements in sprinting, jumping, and cognitive readiness, making them highly effective for adolescent athletes (2, 7) . Small-sided games (SSG)-based warm-ups have also proven effective in enhancing match-specific skills such as passing accuracy by simulating cognitive demands during gameplay (11) . However, some studies have reported no significant effects of different warm-up protocols on performance, highlighting the need for tailored approaches (14) . The anabolic-catabolic balance, governed by testosterone and cortisol, plays a vital role in long-term athlete development. Hormonal fluctuations reflect training intensity and suggest that well-designed warm-ups could support recovery and optimize physiological readiness (10) . Emerging evidence indicates that structured warm-up protocols enhance acute performance in youth athletes through neuromuscular priming and metabolic efficiency, which improves motor unit recruitment and proprioceptive acuity (3, 10) . Vigorous exercise intensity has been shown to elevate cortisol levels while transiently increasing testosterone, with implications for hormonal balance and cognitive performance (10, 12) . Recent studies have explored how exercise intensity influences hormonal changes and performance in youth soccer players. Cortisol levels fluctuate throughout the season, with the lowest levels observed mid-season, indicating reduced peripheral fatigue during this period (41) . Endocrine markers, such as testosterone and cortisol, have demonstrated correlations with fitness parameters like VO2max, countermovement jump, and isometric strength, although no significant differences were found between playing positions (20, 26) . These findings underscore the complex interplay between hormonal changes, physical performance, and match participation in adolescent soccer players (27) . Environmental factors, such as heat, necessitate tailored warm-ups to maintain performance and comfort. Evidence suggests that passive heating during warm-ups can aid performance during transition periods (15) . Comprehensive fatigue management strategies, including structured warm-ups, are vital in preventing performance declines and supporting long-term athlete development (3, 25) . This study’s approach to comparing six evidence-based warm-up protocols addresses a significant gap by evaluating hormonal, biochemical, and performance outcomes. It provides practical insights for coaches to design warm-ups that optimize performance, minimize fatigue, and support long-term development in adolescent soccer players. This project is registered on https://irct.behdasht.gov.ir/ (ID: IRCT20241123063806N1) and has been approved by the Research Ethic Committees of Islamic Azad university-Isfahan (Khorasgan) Branch (IR.IAU.KHUISF.REC.1403.419). In all aspects, this trial will be conducted according to the Declaration of Helsinki on Human Research. Players U15 from the Nesf-e-Jahan Soccer team (present in the first division of grassroots football league in Isfahan province) will be invited to participate. Written consent will be obtained before participation from the team club and parents. Abbreviations (HR): Heart Rate (LDH): Lactate Dehydrogenase (PAP): Post-Activation Potentiation (A/C): Anabolic-Catabolic balance (DWU): Dynamic Warm-up (SSGW): Small-Sided Games Warm-Up (IWU): Integrated Warm-Up (AWP): Analytical Warm-up (RPE): The rate of perceived exertion Yo-Yo-1: Intermittent Endurance Test level one (RAST): Running Based Anaerobic Sprint Test (WAnT): Wingate anaerobic test (CoD): Change of Direction (CMJ): Countermovement Jump Declarations Ethics approval and consent to participate The study protocol was approved by the Islamic Azad University–Isfahan (Khorasgan) Branch Research Ethics Committee (IR.IAU.KHUISF.REC.1403.419). Written informed consent will be obtained from all participants and their legal guardians before inclusion, in accordance with the Declaration of Helsinki. Consent for publication Not applicable (no individual data are reported). Availability of data and materials De-identified participant data will be made available upon reasonable request from the corresponding author, in compliance with data protection regulations . Competing interests The authors declare no competing interests. Funding Statement This work was supported by the Islamic Azad University, Isfahan (Khorasgan) Branch, Faculty of Physical Education and Sports Sciences (FPESS) [Thesis number IR.IAU.KHUISF 162964572/2024]. However, no external funding or financial support was allocated to this research. The funder had no role in the study design, data collection, analysis, interpretation, writing of the report, or the decision to submit the paper for publication. All financial responsibilities related to this research, including data collection, analysis, interpretation, and manuscript preparation, were entirely borne by the student. Authors' contributions H.Z., K.J.D., and F.T. contributed to the study conception and design. F.M.C. provided expertise on methodology and outcome measures. All authors participated in drafting and revising the manuscript, and approved the final version. Acknowledgements The authors acknowledge the cooperation of the Nesf-e-Jahan Soccer Club and its players. We also thank the laboratory staff of Farabi Super specialty Hospital, Isfahan (Ms.Malahat Alinezhad: [email protected] and Mohmnad Bateni: [email protected] for assistance with biochemical analyses. References Rowat O. Technical and physical determinants of soccer matc. 2017. Ferraz R, Ribeiro P, Neiva HP, Forte P, Branquinho L, Marinho DA. Characterization of warm-up in soccer: Report from Portuguese elite soccer coaches. The Open Sports Sciences Journal. 2021;14(1):114-23. Hammami A, Zois J, Slimani M, Russell M, Bouhel E. The efficacy, and characteristics of, warm-up and re-warm-up practices in soccer players: A systematic review. The Journal of sports medicine and physical fitness. 2016;58(1-2):135-49. Chaari F, Alkhelaifi K, Rahmani A, Peyrot N, Boughattas W, Hadadi A, et al. Acute effect of core stability exercises on static and dynamic postural balance in soccer players with groin pain. Scientific Reports. 2025;15(1):9086. Hackney AC, Elliott-Sale KJ. Exercise endocrinology:“What comes next?”. MDPI; 2021. p. 167-70. Silva JR, Rumpf MC, Hertzog M, Castagna C, Farooq A, Girard O, et al. Acute and Residual Soccer Match-Related Fatigue: A Systematic Review and Meta-analysis. Sports Medicine. 2018;48(3):539-83. Jiménez M, Alvero-Cruz JR, Solla J, García-Bastida J, García-Coll V, Rivilla I, et al. Competition seriousness and competition level modulate testosterone and cortisol responses in soccer players. International Journal of Environmental Research and Public Health. 2020;17(1):350. Perroni F, Fittipaldi S, Falcioni L, Ghizzoni L, Borrione P, Vetrano M, et al. Effect of pre-season training phase on anthropometric, hormonal and fitness parameters in young soccer players. PloS one. 2019;14(11):e0225471. García L, Ceylan H, Silva A, Clemente F, Moreno-Vecino B, González Fernández FT, et al. Relationship between testosterone and cortisol with anthropometric characteristics in professional male soccer players. Retos. 2024;61:919-26. Judek R, Latour E, Latour M, Melnyk B, Rygielski A. The usefulness of the cortisol: testosterone ratio in assessing the catabolic and anabolic balance of athletes. Quality in Sport. 2024;22:54505-. Yıldırım U, Edis Ç. The Effect of Soccer Specific and Traditional Warm-up Protocols on Endurance Performance. International Journal of Sport Exercise and Training Sciences-IJSETS. 2025;11(1):47-53. Pajerska K, Zajac T, Mostowik A, Mrzyglod S, Golas A. Post activation potentiation (PAP) and its application in the development of speed and explosive strength in female soccer players: A review. 2021. Rowell AE, Aughey RJ, Hopkins WG, Esmaeili A, Lazarus BH, Cormack SJ. Effects of training and competition load on neuromuscular recovery, testosterone, cortisol, and match performance during a season of professional football. Frontiers in physiology. 2018;9:668. Kapnia AΚ, Dallas CN, Gerodimos V, Flouris AD. Impact of warm-up on muscle temperature and athletic performance. Research quarterly for exercise and sport. 2023;94(2):460-5. Diekfuss JA, Grooms DR, Hogg JA, Singh H, Slutsky-Ganesh AB, Bonnette S, et al. Targeted application of motor learning theory to leverage youth neuroplasticity for enhanced injury-resistance and exercise performance: OPTIMAL PREP. Journal of Science in Sport and Exercise. 2021;3(1):17-36. Sople D, Wilcox III RB. Dynamic warm-ups play pivotal role in athletic performance and injury prevention. Arthroscopy, Sports Medicine, and Rehabilitation. 2024:101023. Hackney AC. Hormonal exercise response model (HERM): A conceptual framework of endocrine reactivity to the physical stress of exercise. Anatolia sport research. 2020;1(1):1. Dalle S, Hiroux C, Koppo K. Endocannabinoid remodeling in murine cachexic muscle associates with catabolic and metabolic regulation. Biochimica et Biophysica Acta (BBA)-Molecular Basis of Disease. 2024;1870(5):167179. Ruf L. Monitoring Training Load and Responses to Load in Youth Soccer Special Reference to Biological Maturation. 2022. Aloui G, Hermassi S, Bartels T, Hayes LD, Bouhafs EG, Chelly MS, et al. Combined plyometric and short sprint training in u-15 male soccer players: effects on measures of jump, speed, change of direction, repeated sprint, and balance. Frontiers in physiology. 2022;13:757663. Taylor K-L, Sheppard JM, Lee H, Plummer N. Negative effect of static stretching restored when combined with a sport specific warm-up component. Journal of Science and Medicine in Sport. 2009;12(6):657-61. Redd MJ, Starling-Smith TM, Herring CH, Stock MS, Wells AJ, Stout JR, et al. Tensiomyographic responses to warm-up protocols in collegiate male soccer athletes. Journal of Functional Morphology and Kinesiology. 2021;6(4):80. Villaseca-Vicuña R, Gayan-Candia A, Gazzo F, Giraldez J, Zabaloy S, Antonio Gonzalez-Jurado J. Comparison of two warm-up protocols for physical and technical-decisional performance in young football players. Physical Activity Review. 2024;12(1). Coledam DHC, Santos JWd. Efeito agudo do aquecimento realizado através de exercícios dinâmicos e jogo de futebol em campo reduzido sobre a agilidade em crianças. 2011. Scott BR, Lockie RG, Knight TJ, Clark AC, de Jonge XAJ. A comparison of methods to quantify the in-season training load of professional soccer players. International journal of sports physiology and performance. 2013;8(2):195-202. Foster C, Boullosa D, McGuigan M, Fusco A, Cortis C, Arney BE, et al. 25 years of session rating of perceived exertion: historical perspective and development. International journal of sports physiology and performance. 2021;16(5):612-21. Fiorenza M, Hostrup M, Gunnarsson TP, Shirai Y, Schena F, Iaia FM, et al. Neuromuscular fatigue and metabolism during high-intensity intermittent exercise. Medicine and science in sports and exercise. 2019;51(8):1642-52. Póvoas SC, Castagna C, Soares JM, Silva PM, Lopes MV, Krustrup P. Reliability and validity of Yo-Yo tests in 9-to 16-year-old football players and matched non-sports active schoolboys. European journal of sport science. 2016;16(7):755-63. Keir DA, Thériault F, Serresse O. Evaluation of the running-based anaerobic sprint test as a measure of repeated sprint ability in collegiate-level soccer players. The Journal of Strength & Conditioning Research. 2013;27(6):1671-8. Dos' Santos T, McBurnie A, Thomas C, Comfort P, Jones PA. Biomechanical determinants of the modified and traditional 505 change of direction speed test. The Journal of Strength & Conditioning Research. 2020;34(5):1285-96. Santander MD, Anselmi HE, Garcia GC. Evaluation of the maximum speed in a 30-metre sprint among young Argentine football players. Archivos de Medicinadel Deporte. 2022;39(3):132-7. Walker O. Countermovement jump (CMJ). Science for Sport Available at https://www scienceforsport com/countermovement-jump-cmj/# toggle-id-1. 2016. Yang S, Chen H. Physical characteristics of elite youth male football players aged 13–15 are based upon biological maturity. PeerJ. 2022;10:e13282. Gustavsson A, Neeter C, Thomeé P, Grävare Silbernagel K, Augustsson J, Thomeé R, et al. A test battery for evaluating hop performance in patients with an ACL injury and patients who have undergone ACL reconstruction. Knee surgery, sports traumatology, arthroscopy. 2006;14(8):778-88. Holicky J, Jura O, Kandrac R, Süss V. The effect of postural stability on performance in Ronaldo Speed Test in prepubertal soccer players. Sporto mokslas, 2014, nr 1, p 52-56. 2014(1):52-6. Le Moal E, Rue O, Ajmol A, Abderrahman AB, Hammami MA, Ounis OB, et al. Validation of the Loughborough Soccer Passing Test in young soccer players. The Journal of Strength & Conditioning Research. 2014;28(5):1418-26. Balsom P. Evaluation of physical performance. Handbook of sports medicine Football (soccer). 1994:111-6. Rosch D, Hodgson R, Peterson L, Graf-Baumann T, Junge A, Chomiak J, et al. Assessment and evaluation of football performance. the American Journal of sports Medicine. 2000;28(5_suppl):29-39. Impellizzeri FM, Marcora SM, Coutts AJ. Internal and external training load: 15 years on. Int J Sports Physiol Perform. 2019;14(2):270-3. Rodriguez-Giustiniani P, Rollo I, Galloway SD. A preliminary study of the reliability of soccer skill tests within a modified soccer match simulation protocol. Science and Medicine in Football. 2022;6(3):363-71. Coutts AJ, Crowcroft S, Kempton T. Developing athlete monitoring systems: theoretical basis and practical applications. Recovery and Well-being in Sport and Exercise: Routledge; 2021. p. 17-31. Additional Declarations The authors declare potential competing interests as follows: The authors declare no competing interests. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7105813","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Method Article","associatedPublications":[],"authors":[{"id":484316001,"identity":"20272acc-804d-4c2c-8bc3-0b8bbc3ed589","order_by":0,"name":"Hamzeh Zarei","email":"","orcid":"https://orcid.org/0009-0005-8713-6473","institution":"Department of Sport Physiology, Isf.C., Islamic Azad University, Isfahan, Iran","correspondingAuthor":false,"prefix":"","firstName":"Hamzeh","middleName":"","lastName":"Zarei","suffix":""},{"id":484316002,"identity":"1c5429da-2f3d-40b2-b019-ce1d609fcbb2","order_by":1,"name":"Khosro Jalali Dehkordi","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABDklEQVRIie3PMWrDMBSA4ScM7uLGq0zc5goJgbZDSs5iBJ58AA8eFAqaQrMGMvQqMg80+QAeOtRLpw4OXbIU+mSyFGynY6H6F1tG35MM4HL9wTjvHj5MwJO61Zpe2Zv9FFwktFOW+454898Q6IgXEIEzGSw6POFnnk9m/lW5wVX1mjyHCHAqIL6X/WQamzSqKn+hgkRiVr8nigtgWwNBrPvJLc/u2Eb5TIElLRIJNVxLCHi/sGR5JLJWYSPxwRK6GPsaIVOezSMiNJxOgZoICPDGTon2aRrJyheKN7LcVri0/4Kx4YOE1wKPMjePu1BgezJ487JD1nwUq/UQOWd+LjXNGgcAxaUNLpfL9Z/7BrR4WveXnLGUAAAAAElFTkSuQmCC","orcid":"https://orcid.org/0000-0003-0210-5984","institution":"Department of Sport Physiology, Isf.C., Islamic Azad University, Isfahan, Iran","correspondingAuthor":true,"prefix":"","firstName":"Khosro","middleName":"Jalali","lastName":"Dehkordi","suffix":""},{"id":484316003,"identity":"f4843f21-2b85-4cca-824a-a845eefed517","order_by":2,"name":"Farzaneh Taghian","email":"","orcid":"https://orcid.org/0000-0001-9531-2952","institution":"Department of Sport Physiology, Isf.C., Islamic Azad University, Isfahan, Iran","correspondingAuthor":false,"prefix":"","firstName":"Farzaneh","middleName":"","lastName":"Taghian","suffix":""},{"id":484316004,"identity":"1086e7ea-1234-4f6e-ba3f-dc2b3d207f7f","order_by":3,"name":"Filipe Manuel Clemente","email":"","orcid":"https://orcid.org/0000-0001-9813-2842","institution":"Gdansk University of Physical Education and Sport, 80-336 Gdańsk, Poland","correspondingAuthor":false,"prefix":"","firstName":"Filipe","middleName":"Manuel","lastName":"Clemente","suffix":""}],"badges":[],"createdAt":"2025-07-12 05:19:19","currentVersionCode":1,"declarations":{"humanSubjects":true,"vertebrateSubjects":false,"conflictsOfInterestStatement":true,"humanSubjectEthicalGuidelines":true,"humanSubjectConsent":true,"humanSubjectClinicalTrial":true,"humanSubjectCaseReport":false,"vertebrateSubjectEthicalGuidelines":false},"doi":"10.21203/rs.3.rs-7105813/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7105813/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":86770581,"identity":"6ed1d3d5-3952-4a1a-8073-7f2a6a7b0698","added_by":"auto","created_at":"2025-07-15 11:39:09","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":1280945,"visible":true,"origin":"","legend":"\u003cp\u003eStudy design\u003c/p\u003e","description":"","filename":"Figure.1.Studydesign.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7105813/v1/2cabf574218c4ab118b016da.jpg"},{"id":86771099,"identity":"81805e69-95c5-4201-92fd-ab9842d60a94","added_by":"auto","created_at":"2025-07-15 11:47:09","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":2879437,"visible":true,"origin":"","legend":"\u003cp\u003eSchematic of study design\u003c/p\u003e","description":"","filename":"Figure.2.Schematicofstudydesign.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7105813/v1/a6e6d2b7520848f97deda8e6.jpg"},{"id":86770576,"identity":"ba1221af-9ad6-4581-9cf0-caa4ef93743a","added_by":"auto","created_at":"2025-07-15 11:39:08","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":1603273,"visible":true,"origin":"","legend":"\u003cp\u003ea) SSG Warm-up protocol. b) Integrated Warm-up protocol. c) Small sided games + Integrated warm-up protocol.\u003c/p\u003e","description":"","filename":"Figure.3.aSSGWarmupprotocol.bIntegratedWarmupprotocol.cSmallsidedgamesIntegratedwarmupprotocol..jpg","url":"https://assets-eu.researchsquare.com/files/rs-7105813/v1/43794a46953e2b20145bc74a.jpg"},{"id":86770578,"identity":"c7ea9518-531b-4cdd-a870-a4bd2c34c356","added_by":"auto","created_at":"2025-07-15 11:39:09","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":2161052,"visible":true,"origin":"","legend":"\u003cp\u003eschematic of daily research methodology (Functional \u0026amp; Skill Tests)\u003c/p\u003e","description":"","filename":"Figure4..jpg","url":"https://assets-eu.researchsquare.com/files/rs-7105813/v1/e438784ff401b8bc5df238ed.jpg"},{"id":86770568,"identity":"0360ec6c-6f7d-43cb-929c-d6ec17442073","added_by":"auto","created_at":"2025-07-15 11:39:07","extension":"jpg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":1440498,"visible":true,"origin":"","legend":"\u003cp\u003eNutritional considerations, venous blood sampling, and SMS\u003c/p\u003e","description":"","filename":"Figure5.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7105813/v1/6f2375a8e62c91aac52178e1.jpg"},{"id":86771102,"identity":"258142bf-5230-494d-b64c-09e6d7b670a3","added_by":"auto","created_at":"2025-07-15 11:47:17","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":10268272,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7105813/v1/58c5aac6-57c5-41f0-af51-82b345c288cd.pdf"}],"financialInterests":"The authors declare potential competing interests as follows: The authors declare no competing interests.","formattedTitle":"\u003cp\u003e\u003cstrong\u003eComparison of the effects of different warm-up protocols on anabolic-catabolic balance, fatigue, physical readiness, and technical skill measures: Study protocol for a randomized parallel study in young male soccer players\u003c/strong\u003e\u003c/p\u003e","fulltext":[{"header":"WHAT IS ALREADY KNOWN ON THIS TOPIC","content":"\u003cp\u003e\u003cspan dir=\"\"\u003e\u0026rArr;\u003c/span\u003e\u003cspan dir=\"\"\u003e\u0026nbsp;Warm-up routines are essential for enhancing soccer performance, with dynamic protocols improving physical readiness, skill execution, and injury prevention.\u003c/span\u003e\u003c/p\u003e\n\u003cp\u003e\u003cspan dir=\"\"\u003e\u0026rArr;\u003c/span\u003e\u003cspan dir=\"\"\u003e\u0026nbsp;Hormonal markers like testosterone and cortisol are sensitive indicators of training stress and performance readiness in adolescent athletes.\u003c/span\u003e\u003c/p\u003e\n\u003cp\u003e\u0026rArr; Structured warm-ups can optimize neuromuscular and metabolic efficiency while reducing fatigue accumulation.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eWHAT THIS STUDY ADDS\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cspan dir=\"\"\u003e\u0026rArr;\u003c/span\u003e\u003cspan dir=\"\"\u003e\u0026nbsp;This study is the first to compare the acute and chronic effects of six distinct warm-up protocols on physical, technical, and hormonal adaptations in U-15 soccer players\u003cspan dir=\"\"\u003e.\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e\n\u003cp\u003e\u003cspan dir=\"\"\u003e\u0026rArr;\u003c/span\u003e\u003cspan dir=\"\"\u003e\u0026nbsp;It integrates biochemical markers (cortisol, testosterone, LDH) with performance metrics to identify the most effective warm-up strategies for adolescent athletes\u003cspan dir=\"\"\u003e.\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e\n\u003cp\u003e\u003cspan dir=\"\"\u003e\u0026rArr;\u003c/span\u003e\u003cspan dir=\"\"\u003e\u0026nbsp;Findings will provide evidence-based recommendations for designing warm-ups tailored to the unique physiological needs of youth soccer players\u003cspan dir=\"\"\u003e.\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eHOW THIS STUDY AFFECTS RESEARCH, PRACTICE, OR POLICY\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cspan dir=\"\"\u003e\u0026rArr;\u003c/span\u003e\u003cspan dir=\"\"\u003eResults will guide coaches in implementing warm-up protocols that enhance performance and reduce injury risks in adolescent athletes\u003cspan dir=\"\"\u003e.\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e\n\u003cp\u003e\u003cspan dir=\"\"\u003e\u0026rArr;\u003c/span\u003e\u003cspan dir=\"\"\u003e\u0026nbsp;Hormonal and fatigue-related insights may influence training load management and recovery strategies in youth sports\u003cspan dir=\"\"\u003e.\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e\n\u003cp\u003e\u003cspan dir=\"\"\u003e\u0026rArr;\u003c/span\u003e\u003cspan dir=\"\"\u003e\u0026nbsp;This research could shape future policies on warm-up practices in football academies, promoting long-term athletic development\u003cspan dir=\"\"\u003e.\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e"},{"header":"INTRODUCTION","content":"\u003cp\u003eSoccer performance depends on many things. For young players, skills like dribbling and passing matter most, while for professionals, physical strengths such as jumping, power, and endurance are key. Efficient movement might also be important, though it hasn\u0026rsquo;t been fully explored yet.\u003csup\u003e(1)\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003eWarm-up is important for soccer performance, with research showing its importance in enhancing physical condition and performance\u003csup\u003e(2)\u003c/sup\u003e. Dynamic stretching and post activation potentiation exercises have been found to improve acute performance by 3.46% and 4.21%, respectively\u003csup\u003e(3)\u003c/sup\u003e. The FIFA 11+ warm-up program has shown significant increases in strength, jump, speed, and explosive performances. Dynamic stretching as part of a warm-up leads to superior performance in vertical jump, 20-m sprint, and agility tests compared to static stretching\u003csup\u003e(2)\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003eBiochemical parameters play an important role in monitoring the athlete\u0026rsquo;s responses to the imposed training loads since they give abundant information about how athletes evolve\u003csup\u003e(4)\u003c/sup\u003e. Hormonal monitoring helps optimize training loads and prevent burnout and injuries in teen soccer players,\u0026nbsp;in this regard, examining the anabolic /catabolic (A/C) balance is of particular importance\u003csup\u003e(5)\u003c/sup\u003e. The testosterone/cortisol (T/C) ratio and combination of them may be useful to measure the balance between A/C and to indicate the level of wellness/fatigue as a means of avoiding overtraining and overreaching\u003csup\u003e(6)\u003c/sup\u003e. In fact, testosterone and cortisol have been related with that ability to perform soccer skills at high intensity and recovery capacity\u003csup\u003e(7)\u003c/sup\u003e. these hormones play a role in catabolic and anabolic processes and are frequently used in studies as training stress marker\u003csup\u003e(8)\u003c/sup\u003e. These parameters can be estimated for evaluating the degree of muscle damage, hydration/dehydration, inflammation, oxidative damage, and other factors that facilitate the evaluation of the response of the athlete\u0026rsquo;s body to the different exercise or training loads being carried out\u003csup\u003e(9)\u003c/sup\u003e.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eEmerging research underscores the critical role of hormonal monitoring in optimizing athletic development, particularly during puberty when anabolic-catabolic balance significantly influences training adaptations. Recent findings demonstrate that serum cortisol and testosterone levels in adolescent athletes serve as sensitive biomarkers of training stress, with disproportionate cortisol elevations (\u0026gt;20% above baseline) correlating with impaired neuromuscular performance (r = -0.68, p \u0026lt; 0.01) and increased injury risk\u003csup\u003e(10)\u003c/sup\u003e. This endocrine profiling proves especially valuable when assessing warm-up efficacy, as transient hormonal fluctuations during preparatory exercise may dictate subsequent match performance.\u003c/p\u003e\n\u003cp\u003eLactate dehydrogenase (LDH) has emerged as a key indicator of metabolic strain, with post-activity levels reflecting the cumulative cellular stress of athletic performance. A 2025 longitudinal study revealed that adolescent soccer players exhibiting \u0026nbsp;endurance performances are positively affected after high intensity warm-up phases that increase the REP by athletes in the warm-up phase\u003csup\u003e(11)\u003c/sup\u003e.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eWarm-up protocols, while transient in duration, critically prime neuromuscular efficiency, hormonal regulation, and metabolic readiness in soccer players. Emerging evidence highlights that structured warm-ups enhance post-activation potentiation (PAP), optimizing motor unit recruitment and force transmission during subsequent activity\u003csup\u003e(12)\u003c/sup\u003e. This neuromuscular priming is further linked to transient hormonal shifts, including cortisol suppression and testosterone elevation, which modulate anabolic-catabolic balance (A/C) even in the absence of sustained metabolic demand\u003csup\u003e(13)\u003c/sup\u003e. Additionally, warm-up-induced increases in muscle temperature and oxygen kinetics improve movement economy, reducing fatigue accumulation during high-intensity efforts\u003csup\u003e(14)\u003c/sup\u003e. In youth athletes, whose hormonal profiles and neuromuscular plasticity are distinct from adults, tailored warm-ups may amplify skill acquisition while mitigating injury risks via enhanced proprioceptive feedback. Thus, analyzing warm-up strategies provides actionable insights into acute physiological adaptations that indirectly influence long-term performance trajectories\u003csup\u003e(15)\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003eWhile previous investigations have explored warm-up physiological effects, few have integrated hormonal, biochemical, and performance measures in adolescent populations.\u0026nbsp;In a recent review, the potential physiological benefits of stretching exercises and sports performance, key differences, and comparisons with static exercises are considered as critical components of a multifaceted approach\u003csup\u003e(16)\u003c/sup\u003e. while Hackney\u003csup\u003e(17)\u003c/sup\u003e linked a conceptual framework of endocrine reactivity to the physical Stress of exercise, Dalle, S., et al. state that Anabolic/catabolic balance is crucial for athletes, especially under energy restriction or intense training\u003csup\u003e(18)\u003c/sup\u003e\u003csup\u003e.\u003c/sup\u003e A 2022 study tracked hormonal responses in youth soccer players over a season, observing significant changes in testosterone, cortisol, and growth hormone levels due to training intensity\u003csup\u003e(19)\u003c/sup\u003e. This study uniquely synthesizes these domains through a randomized comparison of six evidence-based protocols, addressing critical gaps in youth-specific warm-up guidelines.\u003c/p\u003e\n\u003cp\u003eThis study aims to determine the acute and longitudinal effects of five structured warm-up protocols (Integrated, Analytical, SSG, and combined Analytical+ Dynamic/SSG+ Integrated) versus a dynamic warm-up control on sport-specific adaptations in U-15 soccer players. The primary objective is to identify which protocol(s) most effectively enhance physical performance (aerobic endurance, anaerobic power, explosive strength, sprint, agility), technical execution (dribbling, passing, composite skills), and physiological resilience (anabolic-catabolic balance via cortisol/testosterone ratios, LDH-mediated metabolic stress). A secondary objective is to quantify fatigue dynamics (neuromuscular, musculoskeletal, metabolic) across four timepoints (T1-T4) to assess recovery and sustainability of adaptations. By prioritizing adolescent-specific hormonal and neuromuscular plasticity, this protocol seeks to establish a hierarchy of warm-up efficacy for optimizing performance readiness while reducing injury susceptibility in youth athletes.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResearch question, aim and objectives\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe research question for the randomized parallel study is: What are the effects of different warm-up protocols on anabolic-catabolic balance, fatigue, physical readiness, and technical skill performance in male youth soccer players?\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe study will aim to compare the effects of different warm-up protocols on anabolic-catabolic balance, fatigue, physical readiness, and technical skill performance among semi-elite male youth soccer players (under 15 years), using validated physiological and performance markers.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eTo answer the research question, we have set out to meet the following objectives:\u003c/p\u003e\n\u003col\u003e\n \u003cli\u003eWhat are the acute and chronic effects of different warm-up protocols on serum cortisol and testosterone levels in male youth soccer players\u003cspan dir=\"RTL\"\u003e?\u003c/span\u003e\u003c/li\u003e\n \u003cli\u003eWhat are the acute and chronic effects of different warm-up protocols on blood lactate levels in male youth soccer players\u003cspan dir=\"RTL\"\u003e?\u003c/span\u003e\u003c/li\u003e\n \u003cli\u003eWhat are the acute and chronic effects of different warm-up protocols on fatigue measures in male youth soccer players\u003cspan dir=\"RTL\"\u003e?\u003c/span\u003e\u003c/li\u003e\n \u003cli\u003eIs there an association between hormonal levels (cortisol, testosterone, cortisol/testosterone ratio), lactate and external training load in male youth soccer players\u003cspan dir=\"RTL\"\u003e?\u003c/span\u003e\u003c/li\u003e\n \u003cli\u003eWhat are the effects of different warm-up protocols on aerobic endurance, explosive power, peak sprint speed, anaerobic power, dribbling speed, passing accuracy, and technical skills (F-MARK) in male youth soccer players?\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"METHODS","content":"\u003cp\u003e\u003cstrong\u003eStudy design\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe study will employ a randomized parallel design to collect quantitative data on physical, physiological, and technical performance indicators in U-15 semi-professional male soccer players. Participants will be recruited from the Nesf-e-Jahan Soccer team, which competes in the first division of the grassroots football league in Isfahan province. Prior to participation, written consent will be obtained from the club and the players\u0026rsquo; parents. Context data collection will be carried out over an eight-week period, from June 23, 2024, to August 15, 2024. The data will be gathered on odd days of the week (Sunday, Tuesday, and Thursday) immediately after the pre-season training sessions of the 2024-2025 grassroots football leagues in Isfahan Province\u003cspan dir=\"RTL\"\u003e.\u003c/span\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStudy population\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study is a randomized parallel study design in U-15 male soccer players. This age group has been selected because it is underrepresented in studies implemented In the \u0026nbsp; A/C balance and fatigue with the implementation of different warm-up protocols and examining physical fitness and skill factors in a group of adolescents context\u003csup\u003e(20)\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;Recruitment\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eSeventy-two U-15 players from a first-division Iranian soccer club (Isfahan) will be randomly allocated to six groups: SSG, Analytical, Integrated, SSG+ Integrated, Analytical+ Dynamic, and Dynamic (control). Ethical protocols include parental/player informed consent after club approval and detailed study briefings\u0026nbsp;(Figure 1\u0026amp;2).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eRandomization\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eClub principal, as a person independent of the study, will conceal participant allocation by shaking a bag with all 72 players (3 teams), before baseline testing. Groups will be randomized such that 5 selection from each principal\u0026apos;s try will be allocated to the intervention condition and the other one to the control condition. Using this approach, each group will have an equal chance of being allocated to the intervention condition, while maintaining an appropriate balance of grades across the two conditions.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eInclusion/exclusion criteria\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eInclusion criteria will require players to attend all warm-up sessions and remain healthy and injury-free throughout the study. Eligible participants will have no history of nutritional supplement use, will have completed at least three years of consistent training and competition, and will not have any diagnosed cardiovascular or musculoskeletal conditions. Players will be excluded if they miss more than 20% of training sessions, sustain injuries resulting in absences over three days, or show a decline of 15% or more in two baseline performance tests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSample size\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003ePower analysis G*Power 3.1.9.4 accounted for the study\u0026apos;s 6-group repeated-measures design with multiple outcomes. Estimating a moderate multivariate effect size (\u0026eta;\u0026sup2; = 0.15) based on prior warm-up literature(14), with \u0026alpha;=0.05, power=0.80, and 5 dependent variables, the required sample was 66 (11/group). We increased this to 72 (12/group) to accommodate potential attrition and ensure adequate power for univariate follow-ups to significant results.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eIntervention and control groups\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eOver 8 weeks, four U-15 coaches will administer five different warm-up protocols in the first 20 minutes of each session, three times weekly. The 12-player control group will perform a 16-exercise dynamic warm-up (DWU). All participants will complete physical, skill assessments, and provide blood samples for biochemical analysis\u003csup\u003e(21)\u003c/sup\u003e. Table 1 shows the dynamic warm-up protocol (control group).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 1.\u003c/strong\u003e Dynamic warm-up protocol Taylor et al\u003csup\u003e(21)\u003c/sup\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"97%\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 4px;\"\u003e\n \u003cp\u003eN\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 30px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eExercise\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eDescription\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 4px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e1\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 30px;\"\u003e\n \u003cp\u003eHigh Knee\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003eAlternating knee raises synchronized with arm motion. 3 \u0026times; 20m.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 4px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e2\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 30px;\"\u003e\n \u003cp\u003eButt Flicks\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003eControlled flicking motion of heels toward glutes. 3 \u0026times; 20m (15\u0026ndash;20 reps).\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 4px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e3\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 30px;\"\u003e\n \u003cp\u003eCarioca\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003eLateral crossover steps over 3 \u0026times; 20m each side.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 4px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e4\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 30px;\"\u003e\n \u003cp\u003eDynamic Hamstring Swings\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003eControlled leg swings to full range of motion. 3 \u0026times; 10 reps per leg.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 4px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e5\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 30px;\"\u003e\n \u003cp\u003eDynamic Groin Swings\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003eControlled leg swings targeting groin muscles. 3 \u0026times; 10 reps per leg.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 4px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e6\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 30px;\"\u003e\n \u003cp\u003eArm Swings (Forward/Back)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003eControlled arm swings in both directions. 3 \u0026times; 10 reps per direction.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 4px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e7\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 30px;\"\u003e\n \u003cp\u003eFaster High Knee\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003eHigh-speed alternating knee raises over 4 \u0026times; 10m.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 4px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e8\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 30px;\"\u003e\n \u003cp\u003eSwerving\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003eControlled swerving motion over 2 \u0026times; 30m at 70% max pace.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 4px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e9\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 30px;\"\u003e\n \u003cp\u003eSide Stepping\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003eLateral steps over 2 \u0026times; 30m at 80% max pace.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 4px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e10\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 30px;\"\u003e\n \u003cp\u003eSpiderman Walks\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003eControlled walking motion with wide strides. 1 \u0026times; 20m (10 reps per side).\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 4px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e11\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 30px;\"\u003e\n \u003cp\u003eSideways Low Squat Walks\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003eSquat walk in a sideways motion \u0026times; 10 steps each direction.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 4px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e12\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 30px;\"\u003e\n \u003cp\u003eUpper Body Rotations\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003eControlled rotations of the upper body \u0026times; 10 reps per direction.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 4px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e13\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 30px;\"\u003e\n \u003cp\u003eVertical Jump\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003eExplosive jumps \u0026times; 5 reps (progressive effort 60% \u0026rarr; 90%).\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 4px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e14\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 30px;\"\u003e\n \u003cp\u003eRun Through\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003eSprint intervals: 2 \u0026times; 20m (70%), 2 \u0026times; 20m (80%), 1 \u0026times; 20m (90%).\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 4px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e15\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 30px;\"\u003e\n \u003cp\u003eCountermovement Jump + 5m Sprint\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003eExplosive jump followed by 5m sprint (90% \u0026times; 2, 95% \u0026times; 1).\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 4px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e16\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 30px;\"\u003e\n \u003cp\u003eSprint + Countermovement Jump\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003eSprint for 5m followed by explosive jump \u0026times; 2 sets.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eWarm-Up Protocols\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study involves 24 warm-up sessions over 8 weeks, with players warming up for 20 minutes at the start of training, three times a week. Before and after the program, players complete fitness and skill tests, and provide blood samples both before and after a simulated soccer match. All sessions take place on the same type of field and in similar weather, with nutrition and sleep managed by parents to keep conditions fair. Other training stays the same, so only the warm-up routines are different. Warm-ups are held between 5 and 7 pm, and players avoid hard exercise two days before the initial tests\u003cspan dir=\"RTL\"\u003e.\u003c/span\u003e (figures 4\u0026amp;5) show detail the timeline, session sequencing, and intervals between assessments.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSmall-Sided Games Warm-Up (SSGW)\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe standardized SSG warm-up protocol consisted of three progressive components: (1) a 5-minute aerobic jogging phase, (2) 5 minutes of sport-specific dynamic movements including 20-meter shuttle drills, and (3) a 6-minute technical activation phase using 5v1 rondo drills in a 7\u0026times;7meter grid with 1-minute defender rotations. This 20-minute protocol was adapted from established small-sided game warm-up methodologies\u003csup\u003e(22)\u003c/sup\u003e to optimize physiological and technical preparation while maintaining sport-specificity (Figure.3a).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eIntegrated Warm-Up (IWU)\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe experimental IWU protocol will employ 2\u0026times;10-minute small-sided game (SSG) played on a 20\u0026times;28 m pitch with 1\u0026times;1 m mini-goals and a standard size 5 Mikasa match ball\u0026nbsp;(Figure. 3b). A qualified club physical trainer will supervise all sessions, maintaining game intensity through immediate ball replacement when play is interrupted. To eliminate external influences on exercise intensity, no verbal encouragement will be provided during gameplay. The modified ruleset will include: (1) elimination of throw-ins and corner kicks - with all restarts occurring from midfield, (2) unlimited player contacts, and (3) requirement for complete team advancement into the attacking half for goal validation. This protocol design follows established SSG implementation frameworks used in recent football training studies\u003csup\u003e(23)\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSSG Warm-up (SSGWU) + Integrated Warm-up (IWU)\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eSequential 10-minute phases of SSGW and IWU will be integrated to synergize their physiological and technical benefits while preserving the integrity of their original structures\u0026nbsp;(Figure 3c).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAnalytical warm-up (AWP)\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eBased on Coledam \u0026nbsp;et al\u003csup\u003e(24)\u003c/sup\u003e., it incorporates 12 controlled dynamic drills to refine motor skills and improve coordination (Table2).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 2.\u003c/strong\u003e Analytical warm-up protocol. Coledam et al\u003csup\u003e(24)\u003c/sup\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eN\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eExercise\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eDescription\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e1\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eHigh knee skipping\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eThe player jogs while lifting their knees toward the chest. Support is on the forefoot, with alternating arm movements for balance. Approximately 12-15 knee lifts per leg every 10 seconds (around 180 total repetitions).\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e2\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eDynamic hamstrings swing\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eThe player jogs with alternating arm movements, lifting one extended leg forward before returning to the starting position and repeating with the other leg. 10-12 swings per leg every 10 seconds (around 120 total swings)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e3\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eSquat and run\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eThe player performs a squat, immediately followed by a short burst of running. 8-10 squat-run cycles (depending on intensity).\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e4\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eInward hip circumduction\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eThe player jogs with alternating arm movements, performing an inward circular motion with one hip before returning to the starting position and repeating with the other leg. 10-12 inward hip rotations per leg every 10 seconds (around 120 total rotations).\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e5\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eOutward hip circumduction\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eThe player jogs with alternating arm movements, performing an outward circular motion with one hip before returning to the starting position and repeating with the other leg. 10-12 outward hip rotations per leg every 10 seconds (around 120 total rotations).\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e6\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eLateral side to side jog with left leg\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eThe player moves laterally to the left, leading with the left leg. Feet do not cross, and arms stay open for balance. 8-10 lateral movements to the left and back in each 10-second interval (around 80-100 total).\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e7\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eLateral side to side with right leg\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eThe player moves laterally to the right, leading with the right leg. Feet do not cross, and arms stay open for balance. 8-10 lateral movements to the right and back in each 10-second interval (around 80-100 total).\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e8\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eLunge walk\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eThe player walks forward, performing alternating lunges with each leg. The trunk stays upright, and the arms swing naturally for balance. 8-10 lunges per leg every 10 seconds (around 80-100 total lunges).\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e9\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eButt flicks\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eThe player quickly moves the heels toward the gluteus, while the trunk remains straight, with arms oscillation.\u003c/p\u003e\n \u003cp\u003e2 sets of 20 seconds\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e10\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eBackward running\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eThe player performs a reverse running, so that he travels in the direction his back is facing rather than his front.\u003c/p\u003e\n \u003cp\u003e2 sets of 20 seconds\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e11\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eFast skipping\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eThe player performs a knee raise while advancing. Frequency and range of motion should be considered. The trunk should remain slightly tilted, alternating the arms.\u003c/p\u003e\n \u003cp\u003e2 sets of 20 seconds\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e12\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eBackward running with turn and sprint\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eThe player performs a half-reverse run, then turns and performs a frontal sprint.\u003c/p\u003e\n \u003cp\u003e2 sets of 20 seconds\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eDynamic warm-up (DWP)+ Analytical warm-up (AWP)\u003c/p\u003e\n\u003cp\u003eThis protocol will integrate the two aforementioned warm-up methodologies, beginning with a 10-minute dynamic phase followed by a 10-minute analytical phase. To preserve scientific rigor, every segment will adhere precisely to the original protocols\u0026rsquo; structure and execution standards. The synergistic alignment of these methods is projected to amplify the study\u0026rsquo;s performance outcomes, leveraging their complementary physiological and neuromuscular benefits.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eInternal training Load assessment\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eHeart rate monitor and motion analysis system\u003c/p\u003e\n\u003cp\u003ePlayers\u0026rsquo; heart rates will be tracked in real time with the Polar H10, recording data every second and measuring distance covered. The device connects easily via Bluetooth and ANT+, sending data to Polar Team Pro software, which can monitor up to 60 players at once. This system will help coaches assess training intensity, sprint counts, and recovery status, making it easier to balance workload and rest. To ensure accurate training zones and intensity, the Edwards TRIMP method will be used, which calculates training load by weighing the time spent in different heart rate zones.\u003csup\u003e(25)\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003eThe rate of perceived exertion (RPE)\u003c/p\u003e\n\u003cp\u003eRPE will be used to assess subjective effort immediately following each warm-up protocol. A standardized question (\u0026apos;How was your exercise experience?\u0026apos;) will be administered to maintain consistency in data collection\u003csup\u003e(26)\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003e2.10. External training Load assessment (Functional tests)\u003c/p\u003e\n\u003cp\u003eThe execution sequence and temporal spacing of functional tests are critical determinants of data validity in sports science research, particularly when assessing adolescent athletes with evolving physiological and neuromuscular capacities. This study implements a rigorously structured testing hierarchy informed by established principles of fatigue mitigation, test-retest reliability, and ecological validity. To preserve test integrity, assessments are sequenced according to their metabolic demand and neuromuscular fatigue induction potential, with high-intensity anaerobic tests (e.g., RAST, 30m sprints) separated by \u0026ge;72-hour recovery periods to minimize residual fatigue effects\u003csup\u003e(27)\u003c/sup\u003e. Aerobic capacity evaluations (Yo-Yo IR1) precede anaerobic power tests to avoid glycogen depletion biases, while skill assessments (RST, LSPT) are conducted after physical testing to replicate match conditions where technical execution occurs under physiological strain\u003csup\u003e(28)\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003eThe Yo-Yo Intermittent Endurance Test\u003csup\u003e(28)\u003c/sup\u003e measures aerobic fitness by running 20m shuttles at increasing speeds until exhaustion. The RAST\u003csup\u003e(29)\u003c/sup\u003e assesses anaerobic power with six 35m sprints and short rests. The CoD test.\u003csup\u003e(30)\u003c/sup\u003e checks agility by sprinting, turning sharply, and sprinting back. The Sprint Peak Test\u003csup\u003e(31)\u003c/sup\u003e\u0026nbsp; \u0026nbsp;measures explosive acceleration and top speed over 30m. The CMJ test \u003csup\u003e(32)\u003c/sup\u003e gauges lower-body power through a vertical jump. The Standing Long Jump\u003csup\u003e(33)\u003c/sup\u003e measures horizontal explosive strength. The Hop Left and Right Test\u003csup\u003e(34)\u003c/sup\u003e assesses endurance, strength, and stability by hopping side to side on one leg for 30 seconds\u003cspan dir=\"RTL\"\u003e.\u003c/span\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;External training Load assessment (Skill tests)\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;Dribbling speed test in soccer\u003c/p\u003e\n\u003cp\u003eThe Ronaldo Speed Test (RST) assesses dribbling speed via timed cone navigation and goal scoring, validated through sequential accuracy. Standardized warm-up minimizes bias, ensuring reliable data\u003csup\u003e(35)\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003ePassing skill test\u003c/p\u003e\n\u003cp\u003eThe Loughborough Soccer Passing Test (LSPT) will be used to assess this skill.\u0026nbsp;LSPT is a reliable and valid test, which assesses the multifaceted aspects of soccer skill including passing, dribbling, control, and decision making\u003csup\u003e(36)\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;F-MARK Skill Tests\u003c/p\u003e\n\u003cp\u003eThe F-MARC test battery-a scientifically validated 2.5-hour protocol-precisely evaluates soccer-specific physical capacities by simulating match demands, enabling coaches to benchmark players against peer norms and quantify training adaptations. For enhanced efficiency, this study will implement a focused selection of technical-tactical assessments adapted from Balsom\u0026apos;s handbook\u003csup\u003e(37)\u003c/sup\u003e,and Rosch\u0026apos;s study\u003csup\u003e(38)\u003c/sup\u003e delivering actionable insights while maintaining rigorous sport-specific evaluation standards. Skills that will be reviewed include: juggling (foot); juggling (body); long passing; short passing; shooting (dead ball); shooting from a pass (foot) and heading.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;Biochemical analysis (Blood serum Testosterone/Cortisol/ lactate dehydrogenase (LDH) collection and analysis\u003c/p\u003e\n\u003cp\u003eSerum lactate dehydrogenase (LDH) will be measured spectrophotometrically (Iric-kit/Alpha-Classic); cortisol/testosterone via semi-automatic ELISA (Monoband-method/State fax) at Farabi Laboratory, Isfahan, by expert staff.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;Considerations\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThis study examines 72 adolescent male soccer players from three competitively matched teams (Nesf-e-Jahan Club, Isfahan, Iran). Anthropometrics were assessed at baseline, mid-/post-intervention (4/8 weeks). Accredited coaches supervised HR-monitored training; stable diets minimized confounders. Ethical rigor included parental/institutional consent and pre-season protocols\u003csup\u003e(39)\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003eResearch implementation stages\u003c/p\u003e\n\u003cp\u003eThis study schedules functional and biochemical tests in separate weeks to ensure accurate, reliable, and physiologically sound results\u0026nbsp;(Table 3). By spacing out different tests, the protocol reduces fatigue and ensures accurate results for both performance and hormone measures. This approach follows sports science best practices, respects young athletes\u0026rsquo; real-world demands, and uses clear visual diagrams to document the testing schedule and maintain the study\u0026rsquo;s reliability. (Figure 4)\u0026nbsp;systematically presents the administration timeline for all functional and sport-specific evaluations, providing clear reference points for performance measurement intervals. (Figure 5)\u0026nbsp;offers detailed visualization of SMS\u003csup\u003e(40)\u003c/sup\u003e and its associated biochemical sampling schedule, including baseline (T1), acute response (T2), and follow-up (T3, T4) assessment points. These figures clearly show the study\u0026rsquo;s schedule, helping readers understand the timing of tests and samples. By following standard formats, they also make it easier for others to repeat the study accurately\u003cspan dir=\"RTL\"\u003e.\u003c/span\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 3.\u003c/strong\u003e Research Methodology\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"601\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eGroups\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePre Test\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eindependent variable\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 274px;\"\u003e\n \u003cp\u003e\u003cstrong\u003edependent variable\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePost Test\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eDWU\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;(Control)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003eT2\u003cspan dir=\"RTL\"\u003eو\u003c/span\u003eT1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003eX1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 274px;\"\u003e\n \u003cp\u003eD1, D2, D3, D4, D5, D6, D7, D8, D9, D10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003eT4\u003cspan dir=\"RTL\"\u003eو\u003c/span\u003eT3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSSGW\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003eT2\u003cspan dir=\"RTL\"\u003eو\u003c/span\u003eT1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003eX2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 274px;\"\u003e\n \u003cp\u003eD1, D2, D3, D4, D5, D6, D7, D8, D9, D10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003eT4\u003cspan dir=\"RTL\"\u003eو\u003c/span\u003eT3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAWU\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003eT2\u003cspan dir=\"RTL\"\u003eو\u003c/span\u003eT1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003eX3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 274px;\"\u003e\n \u003cp\u003eD1, D2, D3, D4, D5, D6, D7, D8, D9, D10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003eT4\u003cspan dir=\"RTL\"\u003eو\u003c/span\u003eT3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eIWU\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003eT2\u003cspan dir=\"RTL\"\u003eو\u003c/span\u003eT1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003eX4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 274px;\"\u003e\n \u003cp\u003eD1, D2, D3, D4, D5, D6, D7, D8, D9, D10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003eT4\u003cspan dir=\"RTL\"\u003eو\u003c/span\u003eT3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eDWU+AWU\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003eT2\u003cspan dir=\"RTL\"\u003eو\u003c/span\u003eT1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003eX5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 274px;\"\u003e\n \u003cp\u003eD1, D2, D3, D4, D5, D6, D7, D8, D9, D10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003eT4\u003cspan dir=\"RTL\"\u003eو\u003c/span\u003eT3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSSGW+IWU\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 66px;\"\u003e\n \u003cp\u003eT2\u003cspan dir=\"RTL\"\u003eو\u003c/span\u003eT1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003eX6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 274px;\"\u003e\n \u003cp\u003eD1, D2, D3, D4, D5, D6, D7, D8, D9, D10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003eT4\u003cspan dir=\"RTL\"\u003eو\u003c/span\u003eT3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"5\" valign=\"top\" style=\"width: 601px;\"\u003e\n \u003cp\u003eT1 and T2: measurement of primary variables\u003c/p\u003e\n \u003cp\u003eT3 and T4: measuring the variables after 8 weeks (Follow-up)\u003c/p\u003e\n \u003cp\u003eX1, X2, X3, X4, X5, X6: Warm-up protocols in six groups\u003c/p\u003e\n \u003cp\u003eD1: Internal Training load \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; D2: External Training load \u0026nbsp; \u0026nbsp; \u0026nbsp; D3: Serum cortisol level\u003c/p\u003e\n \u003cp\u003eD4: Testosterone serum level \u0026nbsp; \u0026nbsp; \u0026nbsp;D5: Lactate level \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; D6: Cortisol/testosterone ratio\u003c/p\u003e\n \u003cp\u003eD7: Fatigue indicators \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; D8: Heart rate fluctuations (RHR, MHR, HR reserve, THR)\u003c/p\u003e\n \u003cp\u003eD9: performance factors \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;D10: Skill factors\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003eStatistical analyses\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eData analysis will be employed SPSS 27.0, with six groups (control + five interventions; n=12 each). Mixed-design ANOVA evaluates between/within-group differences, following Shapiro-Wilk (normality), Levene (variance), and Mauchly (sphericity) tests. Bonferroni-adjusted comparisons, ANCOVA, Pearson/regression models, and intention-to-treat principles with MICE imputation ensure rigor. Effect sizes (\u0026eta;\u0026sup2;, Cohen\u0026rsquo;s d) and 95% CIs are reported; independent statisticians maintain objectivity.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eWarm-ups are essential in youth soccer, as they enhance performance, reduce injury risk, and help manage fatigue\u003csup\u003e(4)\u003c/sup\u003e. Neuromuscular training integrated into regular soccer warm-up sessions has shown significant benefits in improving dynamic balance, horizontal jump, and change-of-direction performances, along with boosting self-confidence and reducing cognitive anxiety in highly-trained pubertal soccer players\u003csup\u003e(4, 5)\u003c/sup\u003e. Additionally, structured dynamic warm-ups that combine injury prevention and performance strategies have been reported to lower injury incidence and enhance performance in sub-elite youth players over mid-to-long-term applications\u003csup\u003e(2, 5)\u003c/sup\u003e\u003c/p\u003e\n\u003cp\u003eDynamic warm-ups have consistently demonstrated improvements in sprinting, jumping, and cognitive readiness, making them highly effective for adolescent athletes\u003csup\u003e(2, 7)\u003c/sup\u003e. Small-sided games (SSG)-based warm-ups have also proven effective in enhancing match-specific skills such as passing accuracy by simulating cognitive demands during gameplay\u003csup\u003e(11)\u003c/sup\u003e. However, some studies have reported no significant effects of different warm-up protocols on performance, highlighting the need for tailored approaches\u003csup\u003e(14)\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003eThe anabolic-catabolic balance, governed by testosterone and cortisol, plays a vital role in long-term athlete development. Hormonal fluctuations reflect training intensity and suggest that well-designed warm-ups could support recovery and optimize physiological readiness\u003csup\u003e(10)\u003c/sup\u003e. Emerging evidence indicates that structured warm-up protocols enhance acute performance in youth athletes through neuromuscular priming and metabolic efficiency, which improves motor unit recruitment and proprioceptive acuity\u003csup\u003e(3, 10)\u003c/sup\u003e. Vigorous exercise intensity has been shown to elevate cortisol levels while transiently increasing testosterone, with implications for hormonal balance and cognitive performance\u003csup\u003e(10, 12)\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003eRecent studies have explored how exercise intensity influences hormonal changes and performance in youth soccer players. Cortisol levels fluctuate throughout the season, with the lowest levels observed mid-season, indicating reduced peripheral fatigue during this period\u003csup\u003e(41)\u003c/sup\u003e. Endocrine markers, such as testosterone and cortisol, have demonstrated correlations with fitness parameters like VO2max, countermovement jump, and isometric strength, although no significant differences were found between playing positions\u003csup\u003e(20, 26)\u003c/sup\u003e. These findings underscore the complex interplay between hormonal changes, physical performance, and match participation in adolescent soccer players\u0026nbsp;\u003csup\u003e(27)\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003eEnvironmental factors, such as heat, necessitate tailored warm-ups to maintain performance and comfort. Evidence suggests that passive heating during warm-ups can aid performance during transition periods\u003csup\u003e(15)\u003c/sup\u003e. Comprehensive fatigue management strategies, including structured warm-ups, are vital in preventing performance declines and supporting long-term athlete development\u003csup\u003e\u003cspan dir=\"RTL\"\u003e\u0026nbsp;\u003c/span\u003e\u003c/sup\u003e\u003csup\u003e(3, 25)\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003eThis study\u0026rsquo;s approach to comparing six evidence-based warm-up protocols addresses a significant gap by evaluating hormonal, biochemical, and performance outcomes. It provides practical insights for coaches to design warm-ups that optimize performance, minimize fatigue, and support long-term development in adolescent soccer players.\u003c/p\u003e\n\u003cp\u003eThis project is registered on https://irct.behdasht.gov.ir/ (ID: IRCT20241123063806N1) and has been approved by the Research Ethic Committees of Islamic Azad university-Isfahan (Khorasgan) Branch (IR.IAU.KHUISF.REC.1403.419). In all aspects, this trial will be conducted according to the Declaration of Helsinki on Human Research. Players U15 from the Nesf-e-Jahan Soccer team (present in the first division of grassroots football league in Isfahan province) will be invited to participate. Written consent will be obtained before participation from the team club and parents. \u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003e\u003cstrong\u003e\u0026nbsp;(HR):\u003c/strong\u003e Heart Rate\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan dir=\"RTL\"\u003e \u003c/span\u003e\u003c/strong\u003e\u003cstrong\u003e(LDH):\u003c/strong\u003e Lactate Dehydrogenase\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan dir=\"RTL\"\u003e \u003c/span\u003e\u003c/strong\u003e\u003cstrong\u003e(PAP):\u003c/strong\u003e Post-Activation Potentiation\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e(A/C):\u003c/strong\u003e Anabolic-Catabolic balance\u003cspan dir=\"RTL\"\u003e\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e(DWU):\u003c/strong\u003e Dynamic Warm-up\u003cspan dir=\"RTL\"\u003e\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e(SSGW):\u003c/strong\u003e Small-Sided Games Warm-Up\u003cspan dir=\"RTL\"\u003e\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e(IWU):\u003c/strong\u003e Integrated Warm-Up\u003cspan dir=\"RTL\"\u003e\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e(AWP):\u003c/strong\u003e Analytical Warm-up\u003cspan dir=\"RTL\"\u003e\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e(RPE):\u003c/strong\u003e The rate of perceived exertion\u003cspan dir=\"RTL\"\u003e\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eYo-Yo-1:\u003c/strong\u003e Intermittent Endurance Test level one\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e(RAST):\u003c/strong\u003e Running Based Anaerobic Sprint Test\u003cspan dir=\"RTL\"\u003e\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e(WAnT):\u003c/strong\u003e Wingate anaerobic test\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e(CoD):\u003c/strong\u003e Change of Direction\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e(CMJ):\u003c/strong\u003e Countermovement Jump\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eEthics approval and consent to participate\u003c/p\u003e\n\u003cp\u003eThe study protocol was approved by the Islamic Azad University\u0026ndash;Isfahan (Khorasgan) Branch Research Ethics Committee (IR.IAU.KHUISF.REC.1403.419). Written informed consent will be obtained from all participants and their legal guardians before inclusion, in accordance with the Declaration of Helsinki.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eConsent for publication\u003c/p\u003e\n\u003cp\u003eNot applicable (no individual data are reported).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAvailability of data and materials\u003c/p\u003e\n\u003cp\u003eDe-identified participant data will be made available upon reasonable request from the corresponding author, in compliance with data protection regulations\u003cem\u003e.\u003c/em\u003e\u003cem\u003e\u0026nbsp;\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eCompeting interests\u003c/p\u003e\n\u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e\n\u003cp\u003eFunding Statement\u003c/p\u003e\n\u003cp\u003eThis work was supported by the Islamic Azad University, Isfahan (Khorasgan) Branch, Faculty of Physical Education and Sports Sciences (FPESS) [Thesis number IR.IAU.KHUISF 162964572/2024]. However, no external funding or financial support was allocated to this research. The funder had no role in the study design, data collection, analysis, interpretation, writing of the report, or the decision to submit the paper for publication. All financial responsibilities related to this research, including data collection, analysis, interpretation, and manuscript preparation, were entirely borne by the student.\u003c/p\u003e\n\u003cp\u003eAuthors\u0026apos; contributions\u003c/p\u003e\n\u003cp\u003eH.Z., K.J.D., and F.T. contributed to the study conception and design. F.M.C. provided expertise on methodology and outcome measures. All authors participated in drafting and revising the manuscript, and approved the final version.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAcknowledgements\u003c/p\u003e\n\u003cp\u003eThe authors acknowledge the cooperation of the Nesf-e-Jahan Soccer Club and its players. We also thank the laboratory staff of Farabi Super specialty Hospital, Isfahan (Ms.Malahat Alinezhad: [email protected] and Mohmnad Bateni: [email protected] \u0026nbsp;for assistance with biochemical analyses.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eRowat O. Technical and physical determinants of soccer matc. 2017.\u003c/li\u003e\n\u003cli\u003eFerraz R, Ribeiro P, Neiva HP, Forte P, Branquinho L, Marinho DA. Characterization of warm-up in soccer: Report from Portuguese elite soccer coaches. The Open Sports Sciences Journal. 2021;14(1):114-23.\u003c/li\u003e\n\u003cli\u003eHammami A, Zois J, Slimani M, Russell M, Bouhel E. The efficacy, and characteristics of, warm-up and re-warm-up practices in soccer players: A systematic review. The Journal of sports medicine and physical fitness. 2016;58(1-2):135-49.\u003c/li\u003e\n\u003cli\u003eChaari F, Alkhelaifi K, Rahmani A, Peyrot N, Boughattas W, Hadadi A, et al. 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Physical Activity Review. 2024;12(1).\u003c/li\u003e\n\u003cli\u003eColedam DHC, Santos JWd. Efeito agudo do aquecimento realizado atrav\u0026eacute;s de exerc\u0026iacute;cios din\u0026acirc;micos e jogo de futebol em campo reduzido sobre a agilidade em crian\u0026ccedil;as. 2011.\u003c/li\u003e\n\u003cli\u003eScott BR, Lockie RG, Knight TJ, Clark AC, de Jonge XAJ. A comparison of methods to quantify the in-season training load of professional soccer players. International journal of sports physiology and performance. 2013;8(2):195-202.\u003c/li\u003e\n\u003cli\u003eFoster C, Boullosa D, McGuigan M, Fusco A, Cortis C, Arney BE, et al. 25 years of session rating of perceived exertion: historical perspective and development. International journal of sports physiology and performance. 2021;16(5):612-21.\u003c/li\u003e\n\u003cli\u003eFiorenza M, Hostrup M, Gunnarsson TP, Shirai Y, Schena F, Iaia FM, et al. Neuromuscular fatigue and metabolism during high-intensity intermittent exercise. Medicine and science in sports and exercise. 2019;51(8):1642-52.\u003c/li\u003e\n\u003cli\u003eP\u0026oacute;voas SC, Castagna C, Soares JM, Silva PM, Lopes MV, Krustrup P. Reliability and validity of Yo-Yo tests in 9-to 16-year-old football players and matched non-sports active schoolboys. European journal of sport science. 2016;16(7):755-63.\u003c/li\u003e\n\u003cli\u003eKeir DA, Th\u0026eacute;riault F, Serresse O. Evaluation of the running-based anaerobic sprint test as a measure of repeated sprint ability in collegiate-level soccer players. The Journal of Strength \u0026amp; Conditioning Research. 2013;27(6):1671-8.\u003c/li\u003e\n\u003cli\u003eDos\u0026apos; Santos T, McBurnie A, Thomas C, Comfort P, Jones PA. Biomechanical determinants of the modified and traditional 505 change of direction speed test. The Journal of Strength \u0026amp; Conditioning Research. 2020;34(5):1285-96.\u003c/li\u003e\n\u003cli\u003eSantander MD, Anselmi HE, Garcia GC. 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Recovery and Well-being in Sport and Exercise: Routledge; 2021. p. 17-31.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"Islamic Azad University, Isfahan","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Warmup Exercise, Testosterone/Cortisol Ratio, Fatigue, Athletic Performance, Soccer, Randomized study","lastPublishedDoi":"10.21203/rs.3.rs-7105813/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7105813/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cem\u003e\u003cstrong\u003eIntroduction\u003c/strong\u003e\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eWarm-up routines are essential for optimizing soccer players’ performance, yet their specific effects on adolescents, with unique hormonal and physiological characteristics, remain underexplored. This study aims to identify effective warm-up strategies to enhance physical fitness, technical skills, and fatigue management in youth soccer players under 15 years old.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e\u003cstrong\u003eMethods and Analysis\u003c/strong\u003e\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThe study involves 72 semi-elite male soccer players, randomly assigned to one of six groups: five experimental warm-up protocols (Integrated, Analytical, Small-Sided Games [SSG], Analytical + Dynamic, SSG + Integrated) and one control group performing a standard dynamic warm-up. Participants will complete an eight-week training program with warm-up routines applied for 20 minutes at the start of training sessions, three times per week (24 sessions total). Outcomes assessed include physical performance (endurance, explosive power, sprint speed, and agility), technical skills (dribbling and passing accuracy), physiological markers (testosterone, cortisol, and LDH levels during simulated matches), and fatigue indicators (neuromuscular, musculoskeletal, and metabolic measures). Data will be collected at baseline, post-intervention, and follow-up.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e\u003cstrong\u003eEthics and Dissemination\u003c/strong\u003e\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThis project has been approved by the Research Ethics Committee of Islamic Azad University, Isfahan (Khorasgan) Branch (IR.IAU.KHUISF.REC.1403.419). Findings will be disseminated through peer-reviewed publications and presentations at relevant academic conferences, providing practical recommendations for coaches and trainers to optimize warm-up routines for adolescent soccer players.\u003c/p\u003e","manuscriptTitle":"Comparison of the effects of different warm-up protocols on anabolic-catabolic balance, fatigue, physical readiness, and technical skill measures: Study protocol for a randomized parallel study in young male soccer players","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-07-15 11:38:41","doi":"10.21203/rs.3.rs-7105813/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"c78d10aa-fde9-4755-94f0-38734accc9ce","owner":[],"postedDate":"July 15th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":51427826,"name":"Sports Medicine and Kinesiology"}],"tags":[],"updatedAt":"2025-07-15T11:38:41+00:00","versionOfRecord":[],"versionCreatedAt":"2025-07-15 11:38:41","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7105813","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7105813","identity":"rs-7105813","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}