Feasibility and Reproducibility of the Unsupported Upper Limb Exercise Test And Six-Minute Peg Board Ring Test for Children and Adolescents

Feasibility and Reproducibility of the Unsupported Upper Limb Exercise Test And Six-Minute Peg Board Ring Test for Children and Adolescents | Authorea try { document.documentElement.classList.add('js'); } catch (e) { } var _gaq = _gaq || []; _gaq.push(['_setAccount', 'G-8VDV14Y67G']); _gaq.push(['_trackPageview']); (function() { var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); })(); Skip to main content Preprints Collections Wiley Open Research IET Open Research Ecological Society of Japan All Collections About About Authorea FAQs Contact Us Quick Search anywhere Search for preprint articles, keywords, etc. Search Search ADVANCED SEARCH SCROLL Pediatric Pulmonology This is a preprint and has not been peer reviewed. Data may be preliminary. 1 July 2025 V1 Latest version Share on Feasibility and Reproducibility of the Unsupported Upper Limb Exercise Test And Six-Minute Peg Board Ring Test for Children and Adolescents Authors : Marina Rodrigues 0000-0002-7658-8459 , Renatha Carvalho 0000-0003-0648-2736 , Brenda Vilas-Boas Gomes , Vanessa Pereira Lima , Raquel Annoni , Fernando Holguin , María Teresa Politi , and Fernanda Lanza 0000-0002-4748-6947 [email protected] Authors Info & Affiliations https://doi.org/10.22541/au.175138756.62969790/v1 Published Pediatric Pulmonology Version of record Peer review timeline 286 views 181 downloads Contents Abstract Supplementary Material Information & Authors Metrics & Citations View Options References Figures Tables Media Share Abstract Objective: To evaluate the feasibility and reproducibility of two field tests for upper limbs (Unsupported Upper Limb Exercise Test - UULEX and Six-Minute Pegboard Ring Test - 6PBRT) in children and adolescents. Methods: Feasibility study. Fifteen healthy volunteers aged 6 to 17 years were included. Lung function was performed, followed by: Cardiopulmonary Exercise Test (CPET), UULEX and 6PBRT. The CPET was performed on an upper limb ergometer using an incremental protocol. UULEX: seated arm-raising while holding weighted bars (0.25–2.0 kg) through graded heights; outcome = test duration (min). 6PBRT: seated transfer of rings between lower and upper pegs for 6 min; outcome = total rings moved. For all tests, peak oxygen consumption (VO 2 peak) was also an outcome. The UULEX and 6PBRT were performed twice each (test and retest), 30-minute apart. Feasibility criteria were (i) no major procedural difficulties and (ii) 80% predicted). No volunteers considered the tests challenging. UULEX: Two volunteers (13%) reached the celling (13 min), none reached the floor (1 min). 6MPRT: no ceiling cases, one volunteer (6%) stopped above the floor (206 rings). The UULEX test vs. retest was 9.5 [8.0 - 12.0] min vs. 9.4 [8.2-12.0] min (p = 0.13) (ICC = 0.93 (0.78–0.97), p < 0.001). The 6PBRT test vs. retest was 299 [258-373] rings vs. 340 [244-387] rings (p = 0.05) (ICC = 0.97 (0.91–0.99), p < 0.001). Standard errors were < 10 % of their respective medians. The CPET elicited higher VO 2 peak (22.8 [19.4–26] mL/kg•min -1 ) compared to UULEX (11.8 [10.2-13.6] mL/kg) or 6PBRT (11.6 [9–12] mL/kg) (p = 0.001). Conclusion: Both UULEX and 6PBRT are feasible and reproducible field tests for upper limbs in children and adolescents, providing practical options for upper-limb functional assessment. Introduction Limb muscle dysfunction, mostly defined by weakness and reduced endurance, is seen in patients with chronic respiratory diseases. Systemic inflammation, muscle disuse, mitochondrial impairments, and steroid treatment are some of the causes of muscle dysfunction [1–3]. There is evidence of decreased functional capacity and quality of life related to muscle strength impairment [4, 5]. The assessment is based on direct and indirect evaluation of strength and exercise capacity. The cardiopulmonary exercise test (CPET) is the gold standard for assessing exercise capacity; however, it requires expensive equipment, a specialized team, and does not assess functionality directly [6]. Thus, field tests are quick and practical alternatives for assessing limb capacity; however, they are described primarily for lower limbs in the pediatric population [7, 8]. The Unsupported Upper Limb Exercise Test (UULEX) is an incremental test during which the subject moves a bar from their lap to the highest level they can reach before exhaustion [9]. The UULEX is the test of choice to measure peak unsupported arm exercise capacity in adults [10]. The Six-Minute Pegboard and Ring Test (6MPRT) is commonly used in adults to evaluate upper limb capacity. It consists of the subject moving as many rings as possible in six minutes [11]. Both tests have been used in adults with chronic pulmonary disease to assess upper limb capacity. The feasibility and reproducibility of UULEX and 6MPRT in pediatric populations have not yet been established. The goal of this study is to evaluate the feasibility and reproducibility of the UULEX and 6MPRT tools in healthy children and adolescents. Study Design This is a feasibility study that included children and adolescents. Sample Recruitment and Ethics Statement The sample consisted of healthy volunteers aged 6 to 17 years. Evaluations began after obtaining the Informed Consent Form signed by the responsible party and the Assent Form signed by the child or adolescent. The study was approved by the Research Ethics Committee (CEP) of the Universidade Federal de Minas Gerais (UFMG) under opinion number 4.710.667, dated May 13, 2021. Assessments were conducted at the Pulmonary Laboratory of the Department of Physiotherapy at the UFMG between January and August 2024. Volunteers were recruited from the university community, including children/adolescents and relatives of employees. Inclusion Criteria This study included volunteers aged 6 to 17 years, presumed to be healthy, with normal lung function, defined as Forced Vital Capacity (FVC), Forced Expiratory Volume in the First Second (FEV 1 ), FEV 1 /FVC ratio, and Forced Expiratory Flow at 25-75% of FVC (FEF 25-75%) greater than 80% of the predicted value [12]. Exclusion Criteria Children with acute illness lasting over four weeks, chronic respiratory disease, chronic medication use, any other condition detected on site, inability to follow test instructions, inability to attend two scheduled visits in a week. Procedures All assessments were conducted over two days. The first assessment was lung function and CPET or filed tests, in random order. There were two levels of randomization: to determine whether the CPET or the field tests would be performed; to determine the order of UULEX and 6MPRT (E-image 1). Lung function The lung function was performed using the Medical Graphics® CPX Ultima system (Miami, FL, USA) in accordance with the recommendation. The following variables were registered: FVC; FEV 1 ; FEV 1 /FVC ratio and FEF 25-75%. The data are presented as absolute values and as a percentage of the predicted values for the Brazilian pediatric population [12]. Upper Limb Exercise Test (UULEX) The UULEX is a symptom-limited field and external-paced (60 lifts per minute by audio signal) test [12]. Briefly, the volunteer sits on a chair in front of a chart with color bands numbered from level 1 (the lowest height) to level 8 (the highest height). At the beginning of the test, the volunteer holds a lightweight polyvinyl chloride (PVC) bar (0.2 kg) in a neutral position (on hip). The volunteer lifts the bar, with both hands, from 1 to 8 level. The test begins with a 1-minute warm-up phase, moving the bar from a neutral position to level 1. Following the warm-up, the volunteer repeatedly moves the bar from a neutral position to level 1 for 1 minute. The test progresses by increasing the height by one level each minute, with the volunteer raising the bar from the neutral position to the next level (2, 3, 4…8). Once the volunteer reaches their maximum reachable height, the bar is replaced with a heavier one (0.5 kg), and the volunteer continues the exercise, moving between the neutral position and the highest reachable level. Every minute thereafter, the bar’s weight is progressively increased by 0.5 kg, up to a maximum of 2.0 kg. The UULEX was performed twice (test and retest), 30-minutes apart. The SpO₂ and heart rate (HR) were continuously assessed during the tests. Blood pressure and modified Borg Scale for dyspnea and upper limbs were recorded at the beginning and at the end of the test. Stopping criteria of UULEX included the volunteer’s request because of fatigue, HR exceeding 85% predicted HR (Maximal predicted HR = 208 - 0.7 × age, in bpm) [13], SpO₂ dropping below 82%, or the volunteer being unable to continue performing the test. The outcomes were test duration, HR (absolute and percentage of predicted value)[5]of the best test (longest duration), VO₂peak, VEpeak. Six-Minute Pegboard and Ring Test (6MPRT) The 6MPRT is a time-limited field, self-paced test [11]. Briefly, the volunteer sits on a chair in front of a board with four pins (two lower pins at participant’s shoulder height, two higher pins 20 cm above the lower pins), with 10 rings hanging on each of the lower pegs. The participant must move, during six minutes, as many rings as possible from the lower pins to the upper pins, and vice-versa. The 6MPRT was performed twice (test and retest), 30-minutes apart. The SpO₂ and HR were continuously assessed during the tests; blood pressure and modified Borg Scale, dyspnea and upper limb scores, were recorded at the beginning and at the end of the test. The 6MPRT was stopped because of participant fatigue, HR over 85% predicted HR (Maximal predicted HR = 208 - 0.7 × age, in bpm) [13], or SpO₂ below 82%. The outcomes were maximum number of rings moved and HR (absolute and percentage of predicted value)[5] of the best test (more rings), VO₂peak, VEpeak. Cardiopulmonary Exercise Test (CPET) The CPET was performed using an upper limb cycle ergometer. After a 2-minute freewheeling warm-up, as previously described [6], the workload increased 4 Watts per minute for volunteers under 12 years old, and 6 Watts per minute for those aged 13 and up. This is an incremental test (workload: Watts), targeting a total duration of 6-12 minutes. The volunteer must maintain an ergometer speed between 40 and 60 rpm until exhaustion or inability to maintain the required speed. The SpO 2 , HR and blood pressure were registered each minute. The CPET was stopped for arrhythmia, participant fatigue, or SpO₂ below 82%. A 2-min free-wheeling cool-down followed. The outcomes were workload (Watts), VO₂peak, VEpeak. Feasibility One of the main objectives of feasibility studies is to assess the acceptability and suitability of interventions and study procedures. Accordingly, we logged any participant‑reported or observed difficulties during the field tests (lack of motor coordination, trouble handling the weighted bars in the UULEX, inability to maintain the prescribed cadence in the 6MPRT, or premature test termination) as indicators of feasibility. The ceiling effect is a commonly used criteria to evaluate whether a test is too easy for participants and therefore loses discriminative power [14]. Conversely, the floor effect is used to evaluate if a test is too hard. The ceiling effect for UULEX was set at 13 minutes and for 6MPRT at 648 rings [10,15]. The floor effect for UULEX was set as 1 minute and for 6MPRT at 206 rings [10,15]. A field test is considered feasible if fewer than 15% of participants attain either the ceiling or floor value [14]. Sample Size The sample size was based on previous feasibility research, which indicates that a small cohort is sufficient to verify procedural consistency in the target population [16]. In line with feasibility-study guidelines [17], we therefore recruited 15 participants. Statistical Analysis Continuous variables are expressed as median and interquartile range. Categorical variables are expressed as counts and percentages. Test-retest reliability of the UULEX (test duration) and 6MRPT (rings moved) was assessed with the intraclass correlation coefficient (ICC), interpreted as poor ( 0.9) [18]. The standard error of measurement (SEM) was calculated as SD / √ N. Because the SEM represents measurement error rather than population dispersion, its computation does not assume normality of the underlying scores. UULEX and 6MRPT field test outcomes (SpO₂, HR, blood pressure, VO₂ peak, VE peak, Borg dyspnea and upper limb scores) were compared to CPET using Wilcoxon signed-rank test (for paired samples). The statistical significance level (α) was adjusted for multiple comparisons using the Bonferroni method, resulting in an adjusted α of 0.017. All statistical analyses were performed using SPSS version 22.0. Results Out of the 21 volunteers recruited, six were excluded because they were unable to attend the laboratory twice in one week. Thus, 15 participants were included in the study (Figure S1). The median age was 11 [9 – 15] years-old, 40% were female (n = 6) and all of them had normal lung function (Table 1). No field tests were stopped because of HR over 85% or low SpO 2 . In UULEX, all volunteers stopped because they were unable to follow the pace; whereas in 6MPRT all tests terminated because of upper limb fatigue. Concerning feasibility, all volunteers correctly performed the field tests without difficulties. Regarding ceiling and floor effects, two volunteers (13%) reached the highest UULEX level, and none reached the floor level (Table S1). No participant reached the 6MPRT ceiling effect, and one (6%) stopped just above the 6MPRT floor level (Table S1). UULEX duration was 9.5 [8.0–12.0] minutes at the first test and 9.4 [8.2-12.0] minutes at retest. For 6MPRT, participants moved 299 [258 - 373] rings at the first test and 340 [244–387] rings at the retest. There were no differences between the test and retest overall results for either UULEX or 6MPRT (p 0.13. Retest performance improved in 47% (n = 7) participants (Table S1). Test–retest reproducibility was good-to-excellent: ICC 0.93 [0.78-0.97] for UULEX and 0.97 [0.91-0.99] for 6MPRT (p<0.0001) (Table 2). Both SEM were < 10% of the corresponding medians (Table 3). The CPET showed a higher metabolic demand compared to field tests: VO 2peak 22.8 [19.4-26] mL/kg•min -1 compared to 11.8 [10.2-13.6] ml/kg•min -1 for UULEX and 11.6 [9.0-12.0] mL/kg•min -1 for 6MPRT (p < 0.05). The ventilation (VE peak ) and HR were also higher at CPET compared to UULEX and 6MPRT (Table 4). Discussion This study confirms the feasibility of the UULEX and 6MPRT in healthy children and adolescents. Fewer than 15 % of participants reached the pre-specified ceiling or floor thresholds, indicating no loss of discriminative power. Both tests also showed good to excellent test-retest reproducibility. One of the main challenges contributing to the gap in assessing upper limb muscle function in the pediatric population is the difficulty of obtaining accurate measurements. Thus, upper limb field tests such as UULEX and 6MPRT represent a promising approach for assessing strength and endurance impairments in children with chronic respiratory conditions. Unlike Leite et al. who described poor reproducibility for the 6MPRT in healthy adolescents, yet did not assess feasibility [15], our data establish both psychometric properties. Participants reported no procedural difficulties; many even described the tests as enjoyable (subjective aspect). Only 13 % reached the UULEX ceiling and none neared its floor, while the 6MPRT had no ceiling cases and one floor case (6 %), confirming that neither test is overly easy or demanding for children and adolescents. Taken together, these findings suggest that both the 6MPRT and UULEX have potential for clinical assessment. Test–retest analysis showed strong reliability for both assessments, reflected in small stadard erros, an outcome typical of well-standardised field tests. Similar reliability has been reported for other paediatric field test assessments [19,20]. The close agreement between trials and the small standard errors (all < 10 % of the median) indicate minimal within-subject variability, suggesting that a single trial could be sufficient. However, because of potential learning effects, especially in the pediatric population, we still recommend performing two trials when feasible. As expected, CPET elicited the highest cardiopulmonary demands, confirming its status as the gold standard for maximum exertion testing and mirroring earlier findings [21]. As anticipated, UULEX and 6MPRT generated submaximal responses (HR remained below 85% of the age-predicted maximum and Borg ratings were lower than during CPET), confirming that neither field test is maximal. Although the primary aim of this study was not to directly compare both field tests, UULEX and 6MPRT produced broadly similar physiological profiles. Despite its contributions, this study has some limitations. First, the sample size may limit the generalizability of the findings. However, it is within the range commonly addressed for feasibility studies. Second, all testing was carried out by experienced physiotherapists in a controlled laboratory, so reproducibility in typical clinical environments remains unverified. Looking ahead, having established feasibility, the future goal is to validate the UULEX and 6MPRT field tests in children and adolescents with respiratory chronic diseases, determine their responsiveness to rehabilitation, and derive disease-specific reference values. This study has laid the groundwork for that future research. In conclusion, the UULEX and 6MPRT are feasible, well-tolerated, and exhibit good-to-excellent reproducibility in healthy paediatric participants, with no ceiling or floor effects. These findings provide a solid foundation for extending their use to clinical populations. Acknowledgements The authors would like to express their thanks to the participants. Authors are also thankful for the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) and Pró-reitoria de Pesquisa da Universidade Federal de Minas Gerais (PRPq/UFMG) funding. References 1. Picado C, Fiz JA, Montserrat JM, et al. Respiratory and skeletal muscle function in steroid-dependent bronchial asthma. Am Rev Respir Dis. 1990;141(1):14-20. 2. Gea J, Casadevall C, Pascual S, Orozco-Levi M, Barreiro E. Respiratory diseases and muscle dysfunction. Expert Rev Respir Med. 2012;6(1):75-90. 3. Zhang W, Zhang C, Zhang Y, Zhou X, Dong B, Tan H, Su H, Sun X. Multifaceted roles of mitochondria in asthma. Cell Biol Toxicol. 2024;40(1):85. 4. Özdemir F, Boşnak Güçlü M, Göktaş HE, Oğuzülgen IK. Maximal exercise capacity, peripheral muscle strength, sleep quality, and quality of life in adult patients with stable asthma. J Asthma. 2025;62(4):608-620. 5. Visser E, de Jong K, van Zutphen T, Kerstjens HAM, Ten Brinke A. Muscle function in moderate to severe asthma: Association with clinical outcomes and inflammatory markers. J Allergy Clin Immunol Pract. 2023;11(5):1439-1447.e3. 6. American Thoracic Society; American College of Chest Physicians. ATS/ACCP statement on cardiopulmonary exercise testing. Am J Respir Crit Care Med. 2003;167(2):211-77. 7. Andrade LB, Silva DA, Salgado TL, Figueroa JN, Lucena-Silva N, Britto MC. Comparison of six-minute walk test in children with moderate/severe asthma with reference values for healthy children. J Pediatr (Rio J). 2014;90(3):250-7. 8. Reimberg MM, Pachi JRS, Scalco RS, Serra AJ, Fernandes L, Politti F, et al. Patients with asthma have reduced functional capacity and sedentary behavior. J Pediatr (Rio J). 2020;96(1):53-59. 9. Takahashi T, Jenkins SC, Strauss GR, Watson CP, Lake FR. A new unsupported upper limb exercise test for patients with chronic obstructive pulmonary disease. J Cardiopulm Rehabil. 2003;23(6):430-7. 10. Janaudis-Ferreira T, Beauchamp MK, Goldstein RS, Brooks D. How should we measure arm exercise capacity in patients with COPD? A systematic review. Chest. 2012;141(1):111-20. 11. Zhan S, Cerny FJ, Gibbons WJ, Mador MJ, WY. Development of an unsupported arm exercise test in patients with chronic obstructive pulmonary disease. J Cardiopulm Rehabil. 2006;26(3):180-7. 12. Jones MH, Vidal PCV, Lanza FC, Silva DCFMF, Pitrez PM, Olmedo APBF, et al. Reference values for spirometry in Brazilian children. J Bras Pneumol. 2020;46(3):e20190138. 13. Tanaka H, Monahan KD, Seals DR. Age-predicted maximal heart rate revisited. J Am Coll Cardiol. 2001;37(1):153-6. 14. Lim CR, Harris K, Dawson J, et al. Floor and ceiling effects in the OHS: an analysis of the NHS PROMs data set. BMJ Open. 2015;5:e007765. 15. Leite HR, Queiroz IP, Santos JG, Barroso de Souza FL, Scheidt Figueiredo PH, Lanza FC, et al. Measurement properties of the six-minute pegboard and ring test (6PBRT) in healthy adolescents. J Bodyw Mov Ther. 2021;28:56-61. 16. Sim J, Lewis M. The size of a pilot study for a clinical trial should be calculated in relation to considerations of precision and efficiency. J Clin Epidemiol. 2012;65(3):301-8. 17. Bowen DJ, Kreuter M, Spring B, Cofta-Woerpel L, Linnan L, Weiner D, et al. How we design feasibility studies. Am J Prev Med. 2009;36(5):452-7. 18. Bobak C, Barr P, O’Malley A. Estimation of an inter-rater intra-class correlation coefficient that overcomes common assumption violations in the assessment of health measurement scales. BMC Med Res Methodol. 2018;18(1):93. 19. Lanza FC, Zagatto EP, Silva JC, Selman JP, Imperatori TB, Zanatta DJ, et al. Reference equation for the incremental shuttle walk test in children and adolescents. J Pediatr. 2015;167(5):1057-61. 20. Cacau LAP, Carvalho VO, Dos Santos Pin A, Araujo Daniel CR, Ykeda DS, de Carvalho EM, et al. Reference values for the 6-min walk distance in healthy children age 7 to 12 years in Brazil: Main results of the TC6minBrasil multi-center study. Respir Care. 2018;63(3):339-46. 21. Barboza M, Oliveira C, Mont’Alverne D, Morano M, Lima V, Velloso M. Cardiopulmonary responses during unsupported upper limb exercise tests and limitations in activities of daily living in individuals with chronic obstructive pulmonary disease. Physiother Theory Pract. 2024;40(4):695-703. E-image 1. Study protocol flowchart. CPET : Cardiopulmonary Exercise Test. 6PBRT : Six-Minute Pegboard Ring Test. UULEX : Unsupported Upper Limb Exercise Test. Supplementary Material File (table.docx) Download 126.62 KB Information & Authors Information Version history V1 Version 1 01 July 2025 Peer review timeline Published Pediatric Pulmonology Version of Record 15 Oct 2025 Published Copyright This work is licensed under a Non Exclusive No Reuse License. Collection Pediatric Pulmonology Keywords children and adolescent field test upper limb Authors Affiliations Marina Rodrigues 0000-0002-7658-8459 Universidade Federal de Minas Gerais Escola de Educacao Fisica Fisioterapia e Terapia Ocupacional View all articles by this author Renatha Carvalho 0000-0003-0648-2736 Universidade Federal de Minas Gerais Escola de Educacao Fisica Fisioterapia e Terapia Ocupacional View all articles by this author Brenda Vilas-Boas Gomes Universidade Federal de Minas Gerais Escola de Educacao Fisica Fisioterapia e Terapia Ocupacional View all articles by this author Vanessa Pereira Lima Universidade Federal dos Vales do Jequitinhonha e Mucuri View all articles by this author Raquel Annoni Universidade Federal de Minas Gerais Escola de Educacao Fisica Fisioterapia e Terapia Ocupacional View all articles by this author Fernando Holguin University of Colorado Anschutz Medical Campus Division of Pulmonary Sciences and Critical Care Medicine View all articles by this author María Teresa Politi Universidad de Buenos Aires Departamento de Toxicologia y Farmacologia View all articles by this author Fernanda Lanza 0000-0002-4748-6947 [email protected] Universidade Federal de Minas Gerais Escola de Educacao Fisica Fisioterapia e Terapia Ocupacional View all articles by this author Metrics & Citations Metrics Article Usage 286 views 181 downloads .FvxKWukQNSOunydq8rnd { width: 100px; } Citations Download citation Marina Rodrigues, Renatha Carvalho, Brenda Vilas-Boas Gomes, et al. 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