Fatigue and Low Energy There is evidence to suggest that athlete fatigue is an important contributor to the likelihood of a hamstring strain occurring. Mair et al. (1996) demonstrated that fatigued muscles are able to absorb less energy before reaching the degree of stretch that causes injury than non-fatigued muscles. This is likely to be especially important for hamstring strains caused by the running action, due to the large forces absorbed by the hamstrings during the latter part of the swing phase as the hamstrings decelerate the leg (Garrett, 1990). Fatigue may also play a role in exacerbating muscle imbalance, which as noted above, may contribute to hamstring injury. Rahnama et al. (2003) studied amateur football players and found that the ratio between hamstring and quadriceps strength became greater as the match went on and fatigue developed. The authors note that the amateur status of the participants from this study may contribute to these results, suggesting that a lack of muscular endurance may contribute to the growing imbalance with fatigue and that a potential implication for coaches is to develop the muscular endurance of endurance athletes to reduce the injury risk.