Hamstring strain injuries (HSIs) can be divided into two distinct types based on the action being performed when the injury occurs: ‘stretching-type’ and ‘sprinting-type’ injuries [1, 2]. Sprinting-type hamstring injuries are the most common in football, with the biceps femoris (BF) muscle most frequently injured in this muscle group (80% of all cases) . HSIs in football account for 12-16% of all injuries, and result in 5-6 HSIs per club per season. On average, this equates to missed playing time of 90 days and 15-21 matches per club per season [4, 5].
Activities involving large, fast hamstring strains are associated with the greatest number of injuries. In the last few decades great emphasis has been placed on improving the efficiency of injury prevention (e.g. FIFA 11+ program) . In spite of this, the number of hamstring injuries has not decreased . This is likely due to the fact that the mechanisms of HSI are still not clear.