Hamstrings biomechanics related to running

Hamstring strain injuries (HSI) occur frequently in sports characterised by high-speed running. Consequently, a thorough understanding of hamstring function during running may help clinicians better understand HSI mechanisms and thus develop better injury prevention and rehabilitative interventions. The purpose of this chapter is to provide an overview of hamstring function during running. The current evidence base suggests that the hamstrings are recruited for the entire stance phase of running, as well as during a portion of the swing phase (from mid-swing onwards). During the late swing phase, the hamstrings undergo active lengthening and experience their greatest lengths. Subsequently, it is likely that this portion of the stride cycle is where the hamstrings are injured. The muscle forces produced by each hamstring muscle during this period are sensitive to the running velocity (i.e. greater running velocities are characterised by greater hamstring muscle forces), whilst the peak length is largely invariant amongst high running velocities (>80% max). Of note to clinicians, hamstring function is likely compromised following HSI; however, more research is needed to identify which specific parameters need the most consideration during rehabilitation. The information in this chapter may inform clinicians when developing HSI preventive and rehabilitative interventions.