Effects of Age and Maturation on Lower Extremity Range of Motion in Male Youth Soccer Players.

ABSTRACT: Robles-Palazón, FJ, Ayala, F, Cejudo, A, De Ste Croix, M, Sainz de Baranda, P, and Santonja, F. Effects of age and maturation on lower extremity range of motion in male youth soccer players. J Strength Cond Res 36(5): 1417-1425, 2022-Restricted joint range of motion (ROM) has been considered as a primary risk factor for some sport-related injuries. Consequently, preparticipation assessment of lower extremity joints ROM could help identify youth soccer players at high risk of injury and to aid in the design of tailored age and maturational specific training interventions. The purpose of this study was to analyze and compare the influence of chronological age and maturational stage on several lower extremity ROM measures, as well as to describe the lower extremity ROM profile using a comprehensive approach in youth soccer players. A total of 286 male youth soccer players' ROM were assessed including passive hip (extension [PHE], adduction with hip flexed 90° [PHADHF90°], flexion with knee flexed [PHFKF] and extended [PHFKE], abduction with hip neutral [PHABD] and flexed 90° [PHABDHF90°], external [PHER] and internal [PHIR] rotation), knee (flexion [PKF]) and ankle (dorsiflexion with knee flexed [ADFKF] and extended [ADFKE]) ROMs. Between-group differences were analyzed using a one-way analysis of variance (ANOVA) and magnitude-based decisions. The results only report statistically significant (p < 0.05; d > 0.5) and clinically relevant differences (>8°) for the PKF ROM between U12 vs. U19, and Pre-PHV vs. Post-PHV groups. Furthermore, approximately 40, 35, and 20% of players displayed restrictions in their PHFKE, PKF, and ADFKF ROM values, respectively. These findings emphasize the necessity of prescribing (across all age groups and periods of growth and maturation) compensatory measures in daily soccer training, and these exercises should be equally applied to both limbs with the aim of improving PHFKE, PKF and ADFKF ROM values.

Comprehensive profile of hip, knee and ankle ranges of motion in professional football players.

BACKGROUND: Limited ranges of motion (ROM) have been considered as a primary risk factor for some football injuries, but only a few studies have analyzed differences in lower extremity joints. The main purposes were: 1) to describe the lower extremity ROM profile in professional football players; and 2) to examine differences between goalkeepers and outfield players. METHODS: Eighty-two professional male football players from 4 teams were measured in the 2013 pre-season. Measures of passive hip (flexion with knee flexed [PHFKF] and extended [PHFKE], extension [PHE], abduction [PHA], external [PHER] and internal [PHIR] rotation), knee (flexion [PKF]) and ankle (dorsiflexion with knee flexed [ADFKF] and extended [ADFKE]) ROMs were taken. Magnitude-based inferences exploring differences between player position and limb were made. RESULTS: Overall, 46% of all participants showed restricted PHFKE and/or around 30% showed restricted ADFKF ROM values. Contrarily, most players reported normal PHFKF, PHE, PHIR and PHER as well as PKF ROM scores with percentage values close to 100%. Bilateral meaningful differences for PHA, PHIR and PHER were found in approximately 30% of outfield players and goalkeepers. Statistical analysis found trivial differences between players for PHFKE, PHE, PHIR, PHER, ADFKE and ADFKF. However, moderate differences between players were found for PHFKF, PHA and PKF, with goalkeepers demonstrating higher values than outfield players. CONCLUSIONS: The findings of this study reinforce the necessity of prescribing exercises aimed at improving PHFKE and ADFKF ROM within everyday football training routines. In addition, as some bilateral deficits were observed, unilateral training should be considered where appropriate.

RELIABILITY OF TWO METHODS OF CLINICAL EXAMINATION OF THE FLEXIBILITY OF THE HIP ADDUCTOR MUSCLES.

BACKGROUND: An inadequate level of flexibility of the adductor muscles is one of the most critical risk factors for chronic groin pain and strains. However, measurement methods of adductor muscle flexibility are not well defined. PURPOSE: To determine the inter-session reliability of the biarticular and monoarticular adductor muscle flexibility measures obtained from passive hip abduction with the knee flexed over the edge of the plinth test (PHA) and the passive hip abduction test at 90° of hip flexion (PHA90°). STUDY DESIGN: Clinical Measurement Reliability study. METHODS: Fifty healthy recreational athletes participated in this study. All participants performed the PHA and PHA90° on four different occasions, with a two-week interval between testing sessions. Reliability was examined through the change in the mean between consecutive pairs of testing sessions (ChM), standard error of measurement expressed in absolute values (SEM) and as a percentage of the mean score (%SEM), minimal detectable change at 95% confidence interval (MDC95), and intraclass correlation coefficients (ICC2,k). RESULTS: The findings showed negligible or trivial ChM values for the two adductor flexibility measures analyzed (<2°). Furthermore, the SEM and MDC95 were 2.1° and 5.9° and 2.2° and 6.2° for the measures obtained from the PHA and PHA90°, respectively, with %SEM scores lower than 5% and ICC scores higher than 0.90. CONCLUSION: The findings from this study suggest that the adductor muscle flexibility measures analyzed have good to excellent inter-session reliability in recreational athletes. Thus, clinicians can be 95% confident that an observed change between two measures larger than 5.9° and 6.2° for the flexibility measures obtained from the PHA and PHA90°, respectively, would indicate a real change in muscle flexibility. LEVEL OF EVIDENCE: 2.

Efecto del nivel de experiencia clínica del examinador sobre la validez de criterio y fiabilidad inter-sesión de cinco medidas del rango de movimiento de la flexión dorsal del tobillo / Efeito da nível de experiência clínica do examiner sobre a validade de discrição e confiabilidade inter-sessão de cinco medidas da amplitude de movimento de la flexão dorsal do tornozelo / Effect of the tester level of experience on the criterion-related validity and intersession reliability of five different ankle dorsal flexion range of motion measures

El objetivo de este estudio fue analizar el efecto que el diferente grado de experiencia del examinador tiene sobre la validez de criterio y fiabilidad inter-sesión de las medidas de rango de movimiento de la flexión dorsal del tobillo (ROMFDT) obtenidas en las pruebas: flexión dorsal del tobillo pasiva en decúbito prono y rodilla flexionada (FDPAS), zancada con inclinómetro (FDZAN-INC) y cinta métrica (FDZAN-MET), zancada modificada con taburete (FDZAN-TAB) y zancada modificada con cajón (FDZAN-CAJ). Un total de 17 deportistas recreativos completaron este estudio. Cada participante fue evaluado por dos examinadores con distinto nivel de experiencia (experto y novel) del ROMFDT empleando 5 pruebas exploratorias diferentes en dos sesiones distintas. Los resultados muestran bajos valores de validez para el examinador novel en todas las pruebas de valoración del ROMFDT excepto en la prueba FDZAN-INC (error típico de la estimación estandarizado = 0,5 [pequeño]; Pearson = 0,85 [moderado]; kappa = 0,74 [buena]). El examinador experto presentó niveles altos de fiabilidad inter-sesión en las pruebas FDZAN-INC, FDZAN-MET y FDZAN-CAJ y valores aceptables en las pruebas FDPAS y FDZAN-TAB. El examinador novel obtuvo valores aceptables de fiabilidad en toda las pruebas de valoración excepto en la prueba FDPAS, que fueron considerados como no aceptables. Por lo tanto, se recomienda que tanto los examinadores expertos como noveles utilicen la prueba FDZAN-INC para: (a) identificar a personas con restringida o normal movilidad de la flexión dorsal del tobillo; y (b) monitorizar la eficacia de los programas de intervención aplicados en caso de ser necesarios (AU)

O objetivo deste estudo foi analisar o efeito de diferentes níveis de experiência do examinador tem sobre as medidas de validade de critério e inter-sessões variam de movimento da flexão dorsal do tornozelo (ROMFDT) obtidos em testes de confiabilidade: flexão dorsal passiva do tornozelo propenso e joelho flexionado (FDPAS), caminhar com inclinômetro (FDZAN-INC) e fita (FDZAN-MET), estride fezes modificado (FDZAN-TAB) e estride gaveta modificado (FDZAN-CAJ). Um total de 17 desportistas recreativos completaram o estudo. Ada participante foi avaliado por dois examinadores, com diferentes níveis de conhecimento (especialistas e novatos) de ROMFDT utilizando 5 testes exploratórios diferentes em duas sessões diferentes. Os resultados mostram níveis baixos de validade para o romance examinador em todos os testes, exceto avaliação ROMFDT do FDZAN-INC (erro típico padrão da estimativa = 0,5 [pequena] test; Pearson = 0,85 [moderado]; kappa = 0,74 [boa]). O examinador especialista mostrou altos níveis de confiabilidade inter-sessão de testes e valores aceitáveis em FDPAS e testes FDZAN-TAB, FDZAN-INC, FDZAN-MET e FDZAN-CAJ. Os valores de confiabilidade aceitável novela examinador obtidos em todos os testes, exceto teste de avaliação FDPAS, as quais foram consideradas inaceitáveis. Portanto, recomenda-se que ambos os especialistas e novatos examinadores usar o teste FDZAN-INC: (a) identificar as pessoas com mobilidade reduzida ou dorsiflexion normal de tornozelo; e (b) monitorar a eficácia de programas de intervenção ser aplicado, se necessário (AU)

The purpose of this study was to analyse the effect of the different degree of tester´s experience on the criterion-related validity and the inter-session reliability of the ankle dorsiflexion range of motion measures (ROMADF) obtained from the following tests: passive non weight-bearing test (ADFPAS), weight-bearing lunge test using an inclinometer (ADFLUNINC) and a tape measure (ADFLUN-TAP), modified-weight bearing test with a moveable datum (ADFLUN-DAT) and modified weight bearing test with a box (ADFLUN-BOX). A total of 17 recreational athletes completed this study. Each participant was assessed by 2 testers with different level of experience in the clinical setting (expert and novel) of the ROMADF using 5 assessment tests in two different sessions, with a rest-interval of 72-96 hours. The results showed low validity scores for the novel tester in all the assessment tests except for the ADFLUN-INC test (standardized typical error of the estimate = 0.5 [small] and Pearson coefficient = 0.85 [moderate]; Kappa = 0.74 [good]). The expert tester showed high reliability scores for the ADFLUN-INC, ADFLUN-TAP and ADFLUN-BOX tests and acceptable scores for the ADFPAS and ADFLUN-DAT. The novel tester presented acceptable reliability scores for all the assessment tests except for the ADFPAS, which were considered as nonacceptable. Therefore, we recommend that both the expert and novel testers use the ADFLUN-INC test to: (a) identify subjects with restrained or normal ROMADF and (b) monitor the efficacy of the intervention treatments applied in case of being necessary (AU)

Test-retest reliability of seven common clinical tests for assessing lower extremity muscle flexibility in futsal and handball players.

OBJECTIVE: To determine the inter-session reliability of seven lower limb muscle flexibility measures obtained from the passive hip extension test (PHE), passive hip flexion test (PHF), passive hip abduction test (PHA), passive straight leg raise test (PSLR), modified Thomas test (MTh), the ankle dorsi-flexion with knee extended (ADFKE) and flexed (ADFKF) tests. DESIGN: Repeated measures design. SETTING: Controlled laboratory environment. PARTICIPANTS: 60 futsal and 30 handball players. MAIN OUTCOME MEASURES: Reliability was examined through the change in the mean (ChM), standard error of measurement expressed in absolute values (SEM) and as a percentage of the mean score (%SEM), minimal detectable change (MDC95), and intraclass correlation coefficient (ICC2,k). RESULTS: The findings showed negligible ChM values for all the flexibility measures analysed (<1°). Furthermore, the SEM and MDC95 for each flexibility measure ranged from 1.3° to 2.5° and from 3.8° to 6.9°, respectively, with %SEM scores lower than 10% and ICC scores higher than 0.88. CONCLUSIONS: Clinicians can be 95% confident that an observed change between 2 measures larger than 3.7°, 6.2°, 5.5°, 6.1°, 6.9°, 4.7°, and 5.0° for the flexibility measures obtained from the PHE, PHF, PHA, PSLR, MTh, ADFKE and ADFKF, respectively, likely indicates a real change in muscle flexibility.

Perfil de flexibilidad de la extremidad inferior en jugadores senior de balonmano / Normative data of Lower-limb muscle flexibility in senior handball players / Perfil de flexibilidade de membros inferiores em jogadores de handebol de alto nível

El objetivo de este estudio fue definir los valores de referencia del perfil de flexibilidad de la extremidad inferior en jugadores senior de balonmano. Para ello, se valoró la flexibilidad de los principales grupos musculares de la extremidad inferior (psoas ilíaco, cuádriceps, aductores, isquiosurales, glúteo mayor, gemelo y soleo). 56 jugadores senior de balonmano con más de 9 años de experiencia tomaron parte en este estudio. Los resultados del presente estudio definen como perfil de flexibilidad de la muestra los siguientes valores de referencia: 41,2º para el gemelo, 43,1ºpara el sóleo, 147,8º para el glúteo mayor, 82,9º para la musculatura isquiosural,47,5º para los aductores, 18,5º para el psoas iliaco y 125,2º para el cuádriceps. A su vez, los resultados del presente estudio demuestran que los jugadores de balonmano analizados presentan un perfil de flexibilidad de la extremidad inferior superior a los valores propuestos para población general, a los valores encontrados en sujetos sanos sedentarios, o en personas físicamente activas. De la misma forma, los valores de flexibilidad de los jugadores de balonmano del presente estudio son superiores o similares a los observados en otros deportes (tenis, fútbol, corredores de larga distancia), excepto para la flexibilidad de la musculatura isquiosural y delpsoas iliaco. Finalmente, no se han encontrado desequilibrios musculares contra laterales entre ambos lados corporales en ninguno de los músculos evaluados (AU)

The purpose of this study was to define the normative lower-limb flexibility data in senior handball players. For it, the flexibility of the major lower-limb muscles was evaluated throughout 7 different peak joint ROM assessment tests (iliopsoas, quadriceps, adductors, hamstrings, gluteus, gastrocnemius, soleus). 56 senior handball players with more than 9 years of sports experience took part in this study. The results of this study define the normative data as: 41,2o for the gastrocnemius, 43,1o for the soleus, 147,8o for the gluteus, 82,9o for the hamstrings, 47,5o for the adductors, 18,5o for the iliopsoas, and 125,2o for the quadriceps. The results of the current study demonstrate that the senior handball players assessed have higher normative data of lower-limb flexibility than the previously stabilised flexibility normative data for general population, healthy sedentary adults, as well as for recreationally active adults. Likewise, the normative lower-limb flexibility data for senior handball players are higher or similar than those reported for other sport (tennis, soccer, long distance runners), except for hamstring and iliopsoas flexibility. Finally, no significant differences were found between dominant and non-dominant leg and therefore contra lateral muscle imbalances have been rejected

A simplified version of the weight-bearing ankle lunge test: description and test-retest reliability.

The purpose of this study was twofold: (1) to describe a new version of the weight-bearing ankle lunge test (WBLT) that is simple to administer, that allows clinicians and sports medicine practitioners to directly assess (in degrees) the ankle dorsiflexion range of motion in a very short period of time while adopting a comfortable testing position; as well as (2) to determine the test-retest reliability of the ankle dorsiflexion range of motion measure obtained from the new version of the WBLT. A total of 50 active adults completed this study. All participants performed the new version of the WBLT on three different occasions, with a two-week interval between testing sessions. Reliability was examined through the change in the mean between consecutive pairs of testing sessions (ChM), standard error of measurement (SEM), minimal detectable change at 95% confidence interval (MDC95), and intraclass correlation coefficient (ICC2,k). The findings showed negligible or trivial ChM values for all the flexibility measures analysed (<1°). Furthermore, the SEM and MDC95 scores for the ankle dorsiflexion measure were 1.3 and 3.8 respectively, and the ICC2k was 0.95. Therefore, this study demonstrated that the ankle dorsiflexion measure obtained from the new version of the WBLT has excellent test-retest reliability scores. Thus, an observed change larger than 3.8° from baseline scores after performing a treatment would indicate that a real change in ankle dorsiflexion range of motion was likely.

Determination of the criterion-related validity of hip joint angle test for estimating hamstring flexibility using a contemporary statistical approach.

OBJECTIVE: To examine the criterion-related validity of the horizontal hip joint angle (H-HJA) test and vertical hip joint angle (V-HJA) test for estimating hamstring flexibility measured through the passive straight-leg raise (PSLR) test using contemporary statistical measures. DESIGN: Validity study. SETTING: Controlled laboratory environment. PARTICIPANTS: One hundred thirty-eight professional trampoline gymnasts (61 women and 77 men). ASSESSMENT OF RISK FACTORS: Hamstring flexibility. MAIN OUTCOME MEASURES: Each participant performed 2 trials of H-HJA, V-HJA, and PSLR tests in a randomized order. The criterion-related validity of H-HJA and V-HJA tests was measured through the estimation equation, typical error of the estimate (TEEST), validity correlation (ß), and their respective confidence limits. RESULTS: The findings from this study suggest that although H-HJA and V-HJA tests showed moderate to high validity scores for estimating hamstring flexibility (standardized TEEST = 0.63; ß = 0.80), the TEEST statistic reported for both tests was not narrow enough for clinical purposes (H-HJA = 10.3 degrees; V-HJA = 9.5 degrees). Subsequently, the predicted likely thresholds for the true values that were generated were too wide (H-HJA = predicted value ± 13.2 degrees; V-HJA = predicted value ± 12.2 degrees). CONCLUSIONS: The results suggest that although the HJA test showed moderate to high validity scores for estimating hamstring flexibility, the prediction intervals between the HJA and PSLR tests are not strong enough to suggest that clinicians and sport medicine practitioners should use the HJA and PSLR tests interchangeably as gold standard measurement tools to evaluate and detect short hamstring muscle flexibility.

Inter-session reliability and sex-related differences in hamstrings total reaction time, pre-motor time and motor time during eccentric isokinetic contractions in recreational athlete.

The purposes were twofold: (a) to ascertain the inter-session reliability of hamstrings total reaction time, pre-motor time and motor time; and (b) to examine sex-related differences in the hamstrings reaction times profile. Twenty-four men and 24 women completed the study. Biceps femoris and semitendinosus total reaction time, pre-motor time and motor time measured during eccentric isokinetic contractions were recorded on three different occasions. Inter-session reliability was examined through typical percentage error (CVTE), percentage change in the mean (CM) and intraclass correlations (ICC). For both biceps femoris and semitendinosus, total reaction time, pre-motor time and motor time measures demonstrated moderate inter-session reliability (CVTE<10%; CM<3%; ICC>0.7). The results also indicated that, although not statistically significant, women reported consistently longer hamstrings total reaction time (23.5ms), pre-motor time (12.7ms) and motor time (7.5ms) values than men. Therefore, an observed change larger than 5%, 9% and 8% for total reaction time, pre-motor time and motor time respectively from baseline scores after performing a training program would indicate that a real change was likely. Furthermore, while not statistically significant, sex differences were noted in the hamstrings reaction time profile which may play a role in the greater incidence of ACL injuries in women.

Acute effects of static and dynamic stretching on hamstrings' response times.

The main purposes of this study were to (a) investigate acute effects of static and dynamic lower limb stretching routines on total response time, pre-motor time and motor time of the medial and lateral hamstrings during maximal eccentric isokinetic knee flexion; and (b) determine whether static and dynamic routines elicit similar responses. A total of 38 active adults completed the following intervention protocols in a randomised order on separate days: (a) non-stretching (control condition), (b) static stretching and (c) dynamic stretching. After the stretching or control intervention, total response time, pre-motor time and motor time of the medial and lateral hamstrings were assessed during eccentric knee flexion movements with participants prone. Measures were compared via a mixed-design factorial ANOVA. There were no main effects for total response time, pre-motor time and motor time. The results suggest that dynamic and static stretching has no influence on hamstrings response times (total response time, pre-motor time and motor time) and hence neither form of stretching reduces this primary risk factor for anterior cruciate ligament injury.

[The height target prediction by the Tanner method infra evaluates the final height in youths from the rural area of South East Spain]. / La predicción de la talla diana por el método de Tanner infravalora la talla final en jóvenes de zona rural del sudeste de España.

INTRODUCTION: Assessing the final height of an individual before the end of the growth has clinical utility for monitoring child health. OBJECTIVE: To calculate the target height of a rural population in Southeast Spain and to compare it with the final height. METHODS: A descriptive observational study was performed. 50 young adults were included in the study (44% men) along with 100 biological parents. The selection of young adults was conducted in 2 phases: 1. Retrospective study based on medical records. 2. PROSPECTIVE STUDY: recruitment and anthropometric measurements. Target size and the size deviation were calculated. RESULTS: The final height was 4.44 cm and 6.37cm higher than the expected target height for men and for women, respectively (p<0.001). (p<0.001). The genetic influence differed between males and females, while the final height for males was associated with the paternal height (r = 0.613, p <0.01), for females, no significant association with the height of the father or the mother was found. The age of the greater correlation with the final height was at 10 ys for boys (r = 0.819) and at 14 ys for girls (r = 0.959). The males' final obesity degree correlated with the father's BMI (r = 0.575, p <0.01) and for girls, with the mother's (r = 0.451, p <0.05). CONCLUSIONS: The target height formula underestimates the final size of individuals. It could be useful to perform an anthropometric study at 10 ys in boys and at 14 ys in girls in order to prevent further alterations in size or weight.

Introducción: Conocer la talla final de un individuo antes de finalizar el crecimiento presenta utilidad clínica para el seguimiento de la salud infantil. Objetivo: Calcular la talla diana de una población rural del sudeste de España y comparar con la talla final alcanzada. Métodos: Fueron incluidos 50 jóvenes de 18 a 22 años (44% hombres) y 100 progenitores. La selección de los jóvenes se realizó en 2 fases: 1. Estudio retrospectivo a partir de historias clínicas. 2. Estudio prospectivo: reclutamiento y determinaciones antropométricas. Se calculó talla diana y el desvío de talla. Resultados: La talla final de los chicos fue de 4,44 cm superior a la talla diana (p.

Acute effects of static and dynamic stretching on hamstring eccentric isokinetic strength and unilateral hamstring to quadriceps strength ratios.

The main purposes of this study were to investigate the acute effects of static and dynamic lower limb stretching routines: (a) on peak torque, total external work and joint angle at peak torque of the hamstrings during maximal eccentric isokinetic leg flexion; (b) on unilateral hamstring to quadriceps (H/Q) strength ratios; as well as (c) to determine whether static and dynamic routines elicit similar responses. A total of 49 active adults completed the following intervention protocols in a randomised order on separate days: (a) non-stretching (control condition), (b) static stretching, and (c) dynamic stretching. After the stretching or control intervention, eccentric isokinetic peak torque, the angle of peak torque and total external work were assessed with participants prone at 1.04 and 3.14 rad · s(-1). Unilateral strength ratios of the knee were also recorded. Measures were compared via a fully-within-groups factorial analysis of variance (ANOVA). There were no main effects for eccentric isokinetic peak torque, angle of peak torque, total external work and unilateral H/Q strength ratios. The results suggest that dynamic and static stretching has no influence on eccentric strength profile and unilateral H/Q strength ratios and hence both forms of stretching do not reduce these two primary risk factors for muscle injury.

Validez y fiabilidad de los ratios de fuerza isocinética para la estimación de desequilibrios musculares / Validity and reliability of isokinetic strength ratios for estimating muscle imbalances

Varios índices de fuerza isocinética (bilateral y unilateral) de la rodilla han sido extensivamente empleados para: a) identificar posibles factores de riesgo de lesión del ligamento cruzado anterior (LCA) de la rodilla y/o desgarros de la musculatura isquiosural; b) monitorizar la eficacia de programas de rehabilitación, y c) determinar si un deportista puede regresar al entrenamiento y/o a la competición de forma segura tras haber superado un proceso de rehabilitación. Sin embargo, la precisión de estos índices isocinéticos para evaluar desequilibrios musculares ha sido aceptada en base a conocimientos teóricos y empíricos, y en menor medida a la evidencia científica existente con respecto a su grado de validez y fiabilidad. Por ello, los objetivos de esta revisión bibliográfica fueron: 1) analizar y comparar la validez y la fiabilidad de los índices de fuerza bilateral y unilateral de la rodilla para la estimación y monitorización de posibles desequilibrios musculares, así como 2) aportar valores de referencia para categorizar la función muscular como normal o con riesgo significativo de lesión. Un total de 13 artículos científicos cumplieron los criterios de inclusión y exclusión inicialmente establecidos. Tras el análisis de los estudios se puede concluir que: a) son muy escasos los trabajos científicos que analizan la validez y la fiabilidad de los índices de fuerza bilateral y unilateral (convencional y funcional) para identificar desequilibrios musculares; b) un desequilibrio bilateral menor del 10-15% y un desequilibrio unilateral menor de 45-60% podrían ser un buen umbral de seguridad para reducir la probabilidad de sufrir una lesión de la musculatura isquiosural y del LCA; c) los índices de fuerza de la rodilla parecen presentar moderados valores de fiabilidad absoluta (error estándar de la medida <15%), y d) son necesarios más estudios que aborden la determinación de la fiabilidad y la validez de los índices de fuerza en diferentes modalidades deportivas(AU)

Several isokinetic strength ratios (bilateral and unilateral) of the knee have been extensively used: (i) to identify possible anterior cruciate ligament (ACL) and hamstring strain injury risk factors; (ii) to monitor the effectiveness of rehabilitation programs; and (iii) to determine if an athlete is able to return safely to training and competition sessions after finishing a specific rehabilitation program. However, the precision of these isokinetic strength ratios to evaluate muscle imbalances has been accepted based on theoretical and empirical knowledge, and less based on the scientific evidence regarding their validity and reliability. The purposes of this literature review were: (1) to analyse and compare the validity and reliability of unilateral and bilateral isokinetic strength ratios of the knee for estimating and monitoring possible muscle imbalances; as well as (2) to report cut-off values to categorize the muscle function as normal or with significantly high injury risk. A total of 13 scientific studies fulfilled all the previously established inclusion and exclusion criteria. After analysing all the studies, it was possible to conclude that: (i) very few studies have analysed the validity and reliability of bilateral and unilateral (conventional and functional) isokinetic strength ratios of the knee to identify muscle imbalances; (ii) a bilateral imbalance lower than 10-15% and unilateral imbalances lower than 20-40% could be an appropriate cut-off score to reduce the likelihood of developing hamstring strains and ACL injuries; (iii) the isokinetic strength ratios of the knee appear to present moderate absolute reliability scores (standard error of the measurement <15%); and (iv) more studies are needed to determine the validity and reliability of the isokinetic strength ratios of the knee in different sport modalities(AU)

Reproducibility and concurrent validity of hip joint angle test for estimating hamstring flexibility in recreationally active young men.

The purposes of this study were twofold: (a) to examine the test-retest reproducibility and concurrent validity of the horizontal hip joint angle test (H-HJA) and vertical hip joint angle test (V-HJA) for estimating hamstring flexibility measured with an inclinometer during the passive straight-leg raise test (PSLR) and (b) to determine whether the H-HJA cutoff scores may be used for V-HJA for the detection of short hamstring flexibility in active recreationally young adults. Fifty young men underwent the H-HJA, V-HJA, and PSLR on the right and left legs 3 times in a randomized order with a 4-week interval between trials under a controlled laboratory environment. Reproducibility was examined using coefficient of variation (CV) and intraclass correlation coefficient (ICC3,1) and their respective confidence limits. Regression and kappa correlation analyses were performed to examine the association of H-HJA and V-HJA with the PSLR test, and the 95% limits of agreement between H-HJA and V-HJA were calculated to check if there were differences in the raising scores. The results demonstrated acceptable reproducibility measures for the H-HJA (4.12% CV; 0.93 ICC), V-HJA (4.99% CV; 0.92 ICC), and PSLR (4.83% CV; 0.88 ICC). The H-HJA (R = 0.62) and V-HJA (R = 0.63) results were significantly associated with those of the PSLR. The 95% limits of agreement between the H-HJA and V-HJA reported systematic bias (+7.12 cm) and a wide 95% random error ( ±13.72 cm). This study concluded that the test-retest reproducibility of the H-HJA, V-HJA, and PSLR is acceptable and that the validity of H-HJA and V-HJA is moderate. Furthermore, the H-HJA cutoff scores should not be used for V-HJA for the detection of short hamstring muscles in young adults.

Absolute reliability of five clinical tests for assessing hamstring flexibility in professional futsal players.

OBJECTIVES: To examine the absolute reliability of five methods for estimating hamstring flexibility in professional futsal players. DESIGN: Absolute reliability laboratory study (k=4). METHODS: A total of 46 male futsal players (172.9±4.5 cm; 69.7±7.5 Kg) completed the study. All participants performed each measurement test twice in a randomized order on four different occasions. Absolute reliability was examined through typical percentage error, percentage change in the mean and intraclass correlations (ICC) as well as their respective confidence limits. RESULTS: The findings showed high reliability for the sit and reach test (SRT) (4.48% typical error; 0.84% change in the mean, 0.95 ICC), toe touch test (TT) (5.89% typical error; 2.31% change in the mean, 0.89 ICC) and back-saver sit and reach test (BSSR) (3.73% typical error; 0.51% change in the mean, 0.97 ICC) compared to the passive straight leg raise test (PSLR) (7.6% typical error; 8.86% change in the mean, 0.77 ICC) and modified sit and reach test (MSR) (11.87% typical error; 7.64% change in the mean, 0.84 ICC) which showed moderate reliability. CONCLUSIONS: An observed change larger than 6.72%, 7.55% and 5.59% for baseline SRT, TT and BSSR scores respectively would indicate that a real improvement in hamstring flexibility has occurred. In addition, the clinical reliability of PSLR and MSR are questioned and should be re-evaluated in future research studies.