Article Text
Abstract
Background Lower limb injuries are prevalent in sports involving running, hopping and jumping. Musculoskeletal lower limb stiffness is a modifiable mechanical property that may be related to injury risk in athletes.
Design Systematic Review.
Objective Examine the relationship between musculoskeletal stiffness and lower limb injury in athletes.
Methods Literature searching was undertaken on 3 electronic databases (MEDLINE/SPORTDiscus/google scholar) up to September 2013. All prospective and case-control studies evaluating lower limb MSK stiffness and injury in athletes were included. Two researchers independently extracted outcome data and assessed the quality of included studies using a modified Downs and Black index. Effect sizes were calculated using RevMan software (version 5.2).
Results 11 studies (6 prospective and 5 case controlled) were identified, comprising a total of 474 participants (378 M, 96 F) with a mean age range of 13–39 years. The majority of studies (9 out of 11) were undertaken on international or elite athletes. Quality index scores ranged from 13 to 16 (max 19). Athletes with a history of unilateral lower limb injury displayed less stiffness when compared to their un-injured contralateral sides. Pooled data from three case control studies also found tendon stiffness was significantly lower in athletes with tendinopathy compared to un-injured matched controls (SMD 0.70, 95% CI 0.07–1.48). Data from prospective studies could not be pooled due to clinical heterogeneity. There was a clear trend that athletes with bilateral differences in leg stiffness or higher mean leg stiffness were more likely to develop a non-contact lower limb injury.
Conclusions Case controlled studies show a clear relationship between musculoskeletal stiffness and athletic injury. Prospective research provides further evidence that musculoskeletal stiffness may have an important causal role; however this may be implicated by previous injury.