Abstract
The objectives of this study were to examine the consequences of an acute hamstring
injury on performance and mechanical properties of sprint-running at the time of returning
to sports and after the subsequent ~2 months of regular soccer training after return.
28 semi-professional male soccer players, 14 with a recent history of unilateral hamstring
injury and 14 without prior injury, participated in the study. All players performed
two 50-m maximal sprints when cleared to return to play (Test 1), and 11 injured players
performed the same sprint test about 2 months after returning to play (Test 2). Sprint
performance (i. e., speed) was measured via a radar gun and used to derive linear
horizontal force-velocity relationships from which the following variables obtained:
theoretical maximal velocity (V
0
), horizontal force (F
H0
) and horizontal power (Pmax). Upon returning to sports the injured players were moderately
slower compared to the uninjured players. F
H0 and Pmax were also substantially lower in the injured players. At Test 2, the injured
players showed a very likely increase in F
H0 and Pmax concomitant with improvements in early acceleration performance. Practitioners
should consider assessing and training horizontal force production during sprint running
after acute hamstring injuries in soccer players before they return to sports.
Key words
hamstring strain - injury - sprinting - soccer
