Inovação tecnológica na avaliação da força e da fadiga muscular em jogadores de futebol
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2022
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A inovação tecnológica tem possibilitado a criação e desenvolvimento de dispositivos com boa capacidade de avaliação e monitorização dos principais indicadores de performance e risco de lesão nas diversas modalidades desportivas. Particularmente no futebol, o estudo da força dos músculos dos membros inferiores, e dos dispositivos que possibilitam a sua avaliação, tem merecido grande atenção pela comunidade desportiva, académica e científica, no sentido de melhorar a monitorização da adaptação ao treino, estimar o risco de lesão e de controlar os índices de fadiga.
Uma forma de monitorização da fadiga é através da avaliação da força isométrica (FI), definida como a contração voluntária do músculo, sem alteração do seu comprimento. Apesar de já existirem alguns dispositivos capazes de avaliar a FI no terreno, e dos testes inerentes serem simples de aplicar, a existência de estudos que documentem o impacto de um jogo na fadiga (força isométrica) permanecem escassos, especialmente, nos músculos adutores dos membros inferiores, determinantes para a modalidade e com elevada incidência de lesões.
Objetivos: Desenvolver e adaptar acessórios para uma célula de força sem fios (GripWise) que permitam avaliar no terreno a força isométrica dos músculos adutores dos membros inferiores em jogadores de futebol, possibilitando o cálculo da fadiga muscular induzida por um jogo.
Métodos: Este estudo transversal teve uma amostra constituída por nove jogadores de futebol semiprofissional (23.11 ± 3.24 anos). A FI foi avaliada através da célula GripWise, e pelo teste de Squeeze, antes e após um jogo de futebol (90 minutos). O teste de Squeeze consiste na avaliação da força muscular isométrica, produzida pelos adutores, durante 10 segundos. Os jogadores foram incentivados a realizar a maior força possível contra a célula GripWise, imediatamente antes .e após um jogo completo (pelo menos 90 minutos) de futebol. Para a análise dos dados de força foram realizados os testes de normalidade e o teste T de medidas repetidas para verificação das diferenças. Os dados de força (todos com normalidade) são apresentados em quilogramas de força (kgf) e respetivo desvio padrão, ou em percentagem de alteração, pré versus pós jogo. O valor de significância (p) foi menor que 0,05.
Resultados: Apesar da FI máxima após o jogo apresentar uma redução de, aproximadamente, 14% (36,2 ± 7,3 kgf vs. 31,8 ± 8,8 kgf; p<0,01) houve um jogador que apresentou melhorias da primeira para a segunda avaliação (pré e pós jogo, respetivamente). A FI média teve uma redução de, aproximadamente, 28% (28.44 ± 6.56 kgf vs 20.94 ± 8.48 kgf; p<0,01).
Conclusão: Os nossos resultados permitam concluir que um jogo de futebol é indutor de fadiga muscular e que esta é responsável por uma diminuição dos níveis de FI máxima, imediatamente após a sua ocorrência. Esta fadiga é individual, variando de atleta para atleta, o que implica que a análise dos resultados não esteja circunscrita à análise estatística, uma vez que esta indica que um jogo de futebol, efetivamente, provoca fadiga nos jogadores, mas não refere as alterações individuais, onde houve casos em que a FI máxima não se alterou.
Technological innovation has enabled the creation and development of devices with good capacity to evaluate and monitor the main indicators of performance and risk of injury in various sports. Particularly in soccer, the study of lower limb muscle strength and the devices that allow its assessment have received great attention from the sports, academic and scientific community, in order to improve the monitoring of training adaptation, to estimate the risk of injury and to control fatigue rates. One way to monitor fatigue is by assessing isometric force (IF), defined as the voluntary contraction of the muscle without changing its length. Although there are already some devices capable of assessing IF in the field, and the inherent tests are simple to apply, studies that document the impact of a game on fatigue (isometric strength) remain scarce, especially in the adductor muscles of the lower limbs, crucial for the sport and with high incidence of injury. Objectives: To develop and adapt accessories for a wireless force cell (GripWise) that allow field evaluation of the isometric strength of the lower limb adductor muscles in soccer players, enabling the calculation of game-induced muscle fatigue. Methods: This cross-sectional study had a sample composed of nine semi-professional soccer players (23.11 ± 3.24 years). Isometric strength was assessed using the GripWise cell, and by the Squeeze test, before and after a soccer game (90 minutes). The Squeeze test consists in evaluating the isometric muscle strength, produced by the adductors, for 10 seconds. Players were encouraged to perform as much force as possible against the GripWise cell, immediately before .and after a full (at least 90 minutes) soccer game. For the analysis of the strength data, normality tests and the repeated measures t-test were performed to check for differences. Strength data (all with normality) are presented as kilograms of force (kgf) and its standard deviation, or percentage of change, pre versus post game. Significance value (p) was less than 0.05. Results: Although the maximum IF after the game showed a reduction of, approximately, 14% (36.2 ± 7.3 kgf vs. 31.8 ± 8.8 kgf; p<0.01) there was one player who showed improvement from the first to the second evaluation (pre and post game, respectively). The average IF had a reduction of approximately 28% (28.44 ± 6.56 kgf vs. 20.94 ± 8.48 kgf; p<0.01). Conclusion: Our results allow us to conclude that a soccer game induces muscle fatigue and that this fatigue is responsible for a decrease in the maximum IF levels immediately after its occurrence. This fatigue is individual, varying from athlete to athlete, which implies that the analysis of the results is not limited to statistical analysis, since the latter indicates that a soccer game effectively causes fatigue in players, but does not refer to individual changes, where there were cases in which the maximum FI did not change.
Technological innovation has enabled the creation and development of devices with good capacity to evaluate and monitor the main indicators of performance and risk of injury in various sports. Particularly in soccer, the study of lower limb muscle strength and the devices that allow its assessment have received great attention from the sports, academic and scientific community, in order to improve the monitoring of training adaptation, to estimate the risk of injury and to control fatigue rates. One way to monitor fatigue is by assessing isometric force (IF), defined as the voluntary contraction of the muscle without changing its length. Although there are already some devices capable of assessing IF in the field, and the inherent tests are simple to apply, studies that document the impact of a game on fatigue (isometric strength) remain scarce, especially in the adductor muscles of the lower limbs, crucial for the sport and with high incidence of injury. Objectives: To develop and adapt accessories for a wireless force cell (GripWise) that allow field evaluation of the isometric strength of the lower limb adductor muscles in soccer players, enabling the calculation of game-induced muscle fatigue. Methods: This cross-sectional study had a sample composed of nine semi-professional soccer players (23.11 ± 3.24 years). Isometric strength was assessed using the GripWise cell, and by the Squeeze test, before and after a soccer game (90 minutes). The Squeeze test consists in evaluating the isometric muscle strength, produced by the adductors, for 10 seconds. Players were encouraged to perform as much force as possible against the GripWise cell, immediately before .and after a full (at least 90 minutes) soccer game. For the analysis of the strength data, normality tests and the repeated measures t-test were performed to check for differences. Strength data (all with normality) are presented as kilograms of force (kgf) and its standard deviation, or percentage of change, pre versus post game. Significance value (p) was less than 0.05. Results: Although the maximum IF after the game showed a reduction of, approximately, 14% (36.2 ± 7.3 kgf vs. 31.8 ± 8.8 kgf; p<0.01) there was one player who showed improvement from the first to the second evaluation (pre and post game, respectively). The average IF had a reduction of approximately 28% (28.44 ± 6.56 kgf vs. 20.94 ± 8.48 kgf; p<0.01). Conclusion: Our results allow us to conclude that a soccer game induces muscle fatigue and that this fatigue is responsible for a decrease in the maximum IF levels immediately after its occurrence. This fatigue is individual, varying from athlete to athlete, which implies that the analysis of the results is not limited to statistical analysis, since the latter indicates that a soccer game effectively causes fatigue in players, but does not refer to individual changes, where there were cases in which the maximum FI did not change.
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Orientação: Carlos Eduardo da Silva Teixeira
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MESTRADO EM EXERCÍCIO E SAÚDE, ATIVIDADE FÍSICA, PHYSICAL ACTIVITY, TREINO DA FORÇA, STRENGTH TRAINING