“…This concern is based on the high incidence of hamstring muscle injury in professional football, 5 together with the association between high prevalence of hamstring strain injury and reduced eccentric hamstring strength 6,7 . In fact, the most common mechanism of hamstring muscle strain injury is related to the tissues' failure to tolerate the forces during the sprint 8,9 . To the best of our knowledge, no previous investigation has offered data about the effect on confinement on muscle strength, and thus, it is difficult to anticipate the detraining magnitude experienced by football players and its potential effect on injury risk.…”