Muscle strength and fatigue asymmetry in university football players: Implications for training, injury prevention and rehabilitation

Abstract

Muscle strength and fatigue asymmetries are crucial determinants of football performance and injury susceptibility. Due to the significant occurrence of lower limb injuries in football, especially hamstring strains, comprehending neuromuscular imbalances is crucial for focused training and injury preventive methods. This study assessed muscle strength and fatigue asymmetry in university football players by analysing peak torque values of knee extensors and flexors, hamstring-to-quadriceps (H/Q) ratios, and fatigue responses. A quantitative pre-experimental research methodology was employed to assess isokinetic muscular strength and fatigue asymmetry in 94 male university football players (ages 18–25). Isokinetic strength and fatigue assessments were performed utilising a CSMi Humac Cybex dynamometer, evaluating both the dominant and non-dominant legs. The conventional (Hcon/Qcon) and functional (Hecc/Qcon) H/Q ratios were assessed before and following fatigue to determine muscle balance and vulnerability to injury. The dominant leg had significantly greater eccentric peak torque for both quadriceps and hamstring muscles (p < 0.05). Although conventional H/Q ratios were similar between limbs before and after fatigue (p < 0.05), functional H/Q ratios were markedly elevated in the dominant leg prior to fatigue (p = 0.04), indicating a possible injury risk. Following fatigue, the dominant leg exhibited a significant decrease (47.04 ± 22.17 to 39.40 ± 17.21, p = 0.05) in hamstring strength, underscoring the varying fatigue responses between limbs. Eccentric strength asymmetry and fatigue-induced declines in hamstring function may heighten injury risk in football players. These findings highlight the importance of focused eccentric strength training, fatigue-resistant conditioning, and routine isokinetic evaluations to reduce injury risk in football players. The findings offer significant insights for the development of evidence-based injury prevention and rehabilitation programs
specifically designed for university football players.