Reliability of Dynamic Shoulder Strength Test Battery Using Multi-Joint Isokinetic Device.

This study aimed to determine the absolute and relative reliability of concentric and eccentric flexion, extension, horizontal abduction, and adduction movements of the shoulder using a functional electromechanical dynamometer (FEMD). Forty-three active male university students (23.51 ± 4.72 years) were examined for concentric and eccentric strength of shoulder flexion, extension, horizontal abduction, and horizontal adduction with an isokinetic test at 0.80 m·s-1. Relative reliability was determined by intraclass correlation coefficients (ICCs) with 95% confidence intervals. Absolute reliability was quantified by the standard error of measurement (SEM) and coefficient of variation (CV). Reliability was very high to extremely high for all movements on concentric and eccentric strength measurements (ICC: 0.76-0.94, SEM: 0.63-6.57%, CV: 9.40-19.63%). The results of this study provide compelling evidence for the absolute and relative reliability of concentric and eccentric flexion, extension, horizontal abduction, and horizontal adduction shoulder isokinetic strength tests in asymptomatic adults. The mean concentric force was the most reliable strength value for all tests.

Reliability of a handball specific strength test battery and the association with sprint and throwing performance in young handball players.

BACKGROUND: A greater motivation for coaches to be more involved in assessment could be the development of specific strength tests closer to specific handball tasks. Therefore, the aims were to determine the reliability of a handball specific strength test battery in young handball players using a functional electromechanical dynamometer (FEMD) and to evaluate the association between the strength test battery and performance measurements. METHODS: Thirty-two young handball players (25% males and 75% females) performed a repeated-measurement design over four weeks. The players conducted one session per week, with each measurement consisting of two isometric tests to obtain isometric peak force, and four incremental tests. Moreover, performance handball tests (sprint and throwing velocity [TV]) were recorded. RESULTS: The reliability of the whole handball specific strength tests was very high for the peak and mean strength (ICC=0.70-0.85; CV=8.49-13.99; SEM=0.44-0.67 kg). The step forward had a moderate association with 5 to 10 meters' time. The highest correlation between TVmean was found with the peak strength of standing lift and between TVpeak with peak strength of unilateral throw. The sprint total time could be explained by Body Mass Index and peak strength of the standing lift in the 40% and the TVpeak could be explained by arm span and mean strength of the standing lift in the 68%. CONCLUSIONS: The high reliability for all exercises and the significant correlation with handball performance (sprint time and TV) allow us to include these tests in handball team evaluation and training.

A new reliable device to assess trunk extensors strength.

PURPOSE: This study aimed to examine the reliability of trunk extensor strength assessment with a functional electromechanical dynamometer (FEMD). METHODS: Thirty-one men performed strength assessment at different velocities (V) (V1 = 0.15 m⋅s-1 , V2 = 0.30 m⋅s-1,V3 = 0.45 m⋅s-1) and range of movement (R) (R1 = 25% cm; R2 = 50% cm), and isometric contraction at 90°. Reliability was obtained through the intraclass correlation coefficient (ICC), typical error (TE), and coefficient of variation (CV). RESULTS: The absolute reliability provided stable repeatability of the average eccentric strength in the V1R1 condition (CV = 9.52%) and the maximum eccentric strength in V1R1 (CV = 9.63%) and V2R2 (CV = 9.66%). The relative reliability of the trunk extensor's average strength was good (ICC = 0.77-0.83) for concentric and good (ICC = 0.78-0.85) and moderate (ICC = 0.67-0.74) for eccentric contraction. Also, good (ICC = 0.77-0.81) and moderate (ICC = 0.55-0.74) reliability of the maximum strength were obtained for concentric and eccentric contraction. The most reliable manifestation to evaluate the concentric (CV = 11.33%) and eccentric (CV = 9.52%) strength was the average strength in the V1R1 condition and the maximum strength (CV = 10.29%) to isometric assessment. The average concentric strength in the V2R2 condition (r = 0.69) and the maximum eccentric strength in the V1R1 condition (r = 0.65) were the best related to the maximum isometric strength. CONCLUSIONS: FEMD is a highly reliable device to evaluate trunk extensors strength.

Influence of maximal isometric strength on 20-meter sprint time / Influência da força isométrica máxima sobre o tempo em sprints de 20 metros / Influencia de la fuerza isométrica máxima sobre el tiempo en sprints de 20 metros

ABSTRACT Introduction The squat is an exercise that is widely used for the development of strength in sports. However, considering that not all sports gestures are vertical, it is important to investigate the effectiveness of propulsive force stimuli applied in different planes. Objective The main purpose of this study was to determine the influence of maximum isometric force (MIF) exerted on starting blocks over performance in 5, 10 and 20-meter sprints. Methods Seven high-level male sprinters (mean age ± SD = 28 ± 5.77 years) participated in this study. The variables were: a) MIF in squats and on starting blocks (measured using a functional electromechanical dynamometer [FEMD]), b) time in 5, 10 and 20-m sprints and c) jump height (measured by the squat jump test). For data analysis, a Pearson correlation was performed between the different variables. The criteria for interpreting the strength of the r coefficients were as follows: trivial (<0.1), small (0.1−0.3), moderate (0.3−0.5), high (0.5−0.7), very high (0.7−0.9), or practically perfect (>0.9). The level of significance was p < 0.05. Results There was very high correlation between MIF exerted on starting blocks and performance in the first meters of the sprint (5-m: r = -0.84, p = 0.01). However, there was small correlation between MIF in squats and performance in the first meters of the sprint (5-m: r = -0.22, p < 0.62). Conclusion The MIF applied on starting blocks correlates very high with time in the first meters of the sprint in high-level athletes. In addition, the use of the FEMD provides a wide range of possibilities for evaluation and development of strength with a controlled natural movement. Level of evidence IV; Prognostic Studies - Case series.

RESUMO Introdução O agachamento é um exercício amplamente utilizado para o desenvolvimento de força nos esportes. No entanto, considerando que nem todos os gestos esportivos são verticais, é importante investigar a eficácia dos estímulos de força propulsiva em diferentes planos. Objetivo O principal objetivo deste estudo foi determinar a influência da força isométrica máxima (FIM) exercida em os blocos de largada sobre o desempenho em sprints de 5, 10 e 20 metros. Métodos Sete velocistas de alto nível do sexo masculino (média ± DP = 28,0 ± 5,77 anos) fizeram parte deste estudo. As variáveis foram: a) FIM no agachamento e nos blocos de largada (avaliados com um dinamômetro eletromecânico funcional (DEF)), b) tempo de sprints de 5, 10 e 20 metros e c) altura do salto (medida pelo teste de squat jump). Para análise dos dados, foi usada a correlação de Pearson entre as diferentes variáveis. Os critérios para interpretar o coeficiente r foi: nulo (< 0,1), pequeno (0,1 a 0,3), moderado (0,3 a 0,5), alto (0,5 a 0,7), muito alto (0,7 a 0,9) ou praticamente perfeito (> 0,9). O nível de significância foi p < 0,05. Resultados Houve correlação muito alta entre a FIM exercida nos blocos de largada e o desempenho nos primeiros metros do sprint (5-m: r = -0,84, p = 0,01). No entanto, a correlação entre o agachamento da FIM e os primeiros metros de sprint foi pequena (5-m: r = -0,22, p < 0,62). Conclusão A FIM aplicada aos blocos de largada teve uma correlação muito alto com o tempo nos primeiros metros de sprint em atletas de alto nível. Além disso, o uso de um DEF oferece uma ampla gama de possibilidades para avaliar e desenvolver força com um movimento natural controlado. Nível de evidência IV; Estudos Prognósticos - Série de casos.

RESUMEN Introducción La sentadilla es un ejercicio ampliamente usado para el desarrollo de fuerza en los deportes. Sin embargo, considerando que no todos los gestos deportivos son verticales, es importante investigar la eficacia de los estímulos de fuerza propulsiva en diferentes planos. Objetivo El principal objetivo de este estudio fue determinar la influencia de la fuerza isométrica máxima (FIM) ejercida en los bloques de salida sobre el rendimiento en sprints de 5, 10 y 20 metros. Métodos Siete velocistas de alto nivel del sexo masculino (promedio ± SD = 28,0 ± 5,7 años) formaron parte de este estudio. Las variables fueron: a) FIM en la sentadilla y en los bloques de salida (evaluados con un dinamómetro electromecánico funcional [DEF]) b) tiempo de sprints de 5, 10 y 20-metros y c) altura del salto (medida a través del test de squat jump). Para el análisis de los datos se usó la correlación de Pearson entre las diferentes variables. Los criterios para interpretar el coeficiente r fueron: nulo (<0,1), pequeño (0,1 a 0,3), moderado (0,3 a 0,5), alto (0,5 a 0,7), muy alto (0,7 a 0,9) o prácticamente perfecto (>0,9). El nivel de significancia fue p < 0,05. Resultados Hubo correlación muy alta entre la FIM ejercida en los bloques de salida y el rendimiento en los primeros metros del sprint (5-m: r = -0,84, p = 0,01). Sin embargo, la correlación entre la FIM en sentadilla y los primeros metros de sprint fue pequeña (5-m: r = -0,22, p < 0,62). Conclusión La FIM aplicada a los bloques de salida tuvo una correlación muy alta con el tiempo en los primeros metros de sprint en atletas de alto nivel. Además, el uso de un DEF ofrece una amplia gama de posibilidades para evaluar y desarrollar fuerza con un movimiento natural controlado. Nivel de evidencia IV; Estudios pronósticos: Serie de casos.