The use of the functional H:Q ratio to assess fatigue in soccer.

The aim of this study was to investigate the effects of fatigue induced by a field test representative of soccer specific movements on different hamstrings:quadriceps ratios in the dominant and non-dominant legs at two different velocities. Eight male football players (age: 21.3+/-2.3 years; height: 178+/-8 cm; body mass: 78+/-9 kg; playing level: British University Southern conference-3B) performed a pre-test to assess the concentric and eccentric strength of the hamstrings and the quadriceps at 60 degrees x s(-1) and 180 degrees x s(-1), The Loughborough Intermittent Shuttle Test (LIST) to simulate soccer, and a post-test similar to the pre-test. The main findings demonstrated significant decreases in the H(con):Q(con) ratio (calculated as the maximal concentric hamstrings strength divided by the maximal concentric quadriceps strength) in the dominant leg at 180 degrees x s(-1) and in the functional ratio H(ecc):Q(con) (calculated as the maximal eccentric hamstrings strength divided by the maximal concentric quadriceps strength) in the dominant leg at 60 degrees x s(-1) and 180 degrees x s(-1). In addition, significant correlations were observed between physiological parameters measured during the soccer-specific exercise and H(ecc):Q(con) only. These results suggested that the functional H(ecc):Q(con) ratio is more representative of fatigue induced by soccer than the conventional H(con):Q(con) ratio. Eccentric strength training at high velocities may be necessary to reduce injury risk in soccer players.