This week I read an ahead-of-print paper by van Beijsterveldt and colleagues (2012) which appeared in the Scandinavian Journal of Medicine & Science in Sports. This is a systematic review of the related studies with the aim to identify risk factors for hamstrings injuries in male adult soccer player.
What we already know
- Hamstring injuries are common and account 12-16% of all injuries in soccer (Arnason et al., 2004).
- Hamstring injuries may lead to an inability to play for up to 90 days and this might also be due to the high reinjury rate observed for this kind of injury.
- Usually, hamstring injury occurs during rapid acceleration, deceleration, change of direction or during the last part of the swing phase of gait.
- Potential risk factors for hamstring injuries are divided to intrinsic (age, previous injury, training history etc) and extrinsic (pitch type, environmental conditions etc).
What they found?
- After evaluating the quality of the related studies, and excluding those with low quality from their analysis, the authors concluded that previous hamstring injury is the most significant risk factor to hamstring injuries.
- Conflicting evidence exists on the role of hamstring length, hamstring flexibility and strength imbalances. In particular, some studies suggest that poor hamstring flexibility is a significant risk factor for hamstring injuries (Witvrouw et al., 2003) and others not (Engebretsen et al., 2010). The same holds for muscle strength imbalances (Croisier et al., 2008; Hagglund et al., 2006).
- Arnason et al. Risk factors for injuries in football. Am J Sports Med 32: 5S-16S, 2004.
- Croisier et al. Strength imbalances and prevention of hamstring injury in professional soccer players: a prospective study. Am J Sports Med 36: 1469-1475, 2008.
- Engebretsen et al. Intrinsic risk factors for hamstring injuries among male soccer players: a prospective cohort study. Am J Sports Med 38: 1147-1153, 2010.
- van Beijsterveldt et al. Risk factors for hamstring injuries in male soccer players: a systematic review of prospective studies. Scand J Med Sci Sports 2012 Jun 21. doi: 10.1111/j.1600-0838.2012.01487.x. [Epub ahead of print].
- Witvrouw et al. Muscle flexibility as a risk factor for developing muscle injuries in male professional soccer players. A prospective study. Am J Sports Med 31: 41-46, 2003.