Peripheral muscle function during repeated changes of direction in professional soccer players.

PURPOSES

To evaluate peripheral muscle function of the knee extensors during repeated changes of direction in professional soccer players by examining differences between competitive levels, periods of the season and playing positions, and to investigate the relationships between peripheral muscle function and physical activities during matches.

METHODS

Knee extensor peripheral muscle function (twitch peak torque, PT) of 593 male soccer players from 13 European professional clubs competing at 3 different levels was evaluated 4 times during the season. The main outcomes were PT (maximal PT, muscle contractility), MP (maximal metabolic power exercise intensity) and PT (PT decline, muscle fatigability) obtained during intermittent runs of increasing intensity with multiple changes of direction interspersed with electrically evoked contractions. Relative total and sprint distances covered during a whole match and during short intervals were quantified from a sub-sample.

RESULTS

PT and MP were higher for first than for second division (p < 0.047; d = 0.15-0.23) and Under-19 players (p < 0.007; d = 0.17-0.25). MP was lower (p < 0.016; d = 0.23-0.32) and PT was higher (p < 0.004; d = 0.26-0.39) in the pre-season compared to all the other time points. MP was higher for fullbacks than attackers and defenders (p < 0.041; d = 0.20-0.22). PT was higher for defenders than fullbacks, midfielders and wings (p < 0.029; d = 0.21-0.28). PT was associated with whole-match relative total distance (p = 0.004; d = 0.26). PT was associated with whole-match relative total distance and relative short-interval sprint distance (p < 0.050; d = 0.18-0.22).

CONCLUSION

The ability to sustain repeated change of direction efforts at high intensities while preserving peripheral muscle function should be considered an important determinant of soccer physical performance.