Prevention of ankle sprain, the most common sporting injury, is only possible once risk factors have been identified. Voluntary strength, proprioception, postural sway, and range of motion are possible risk factors. A systematic review was carried out to investigate these possiblities. Eligible studies were those with longitudinal design investigating ankle sprain in subjects aged >15 years. The studies had to have measured range of motion, voluntary strength, proprioception, or postural sway before monitoring incidence of lateral ankle sprain. Dorsiflexion range strongly predicted risk of ankle sprain. Postural sway and possibly proprioception were also predictors. Therefore the preliminary evidence suggests that people with reduced ankle dorsiflexion range may be at increased risk of ankle sprain. A large number of people do not recover after an ankle sprain and continue to experience disabling consequences such as functional instability, recurrence, and pain six months after injury. 1 2 The development of prevention programmes or preventive behaviours is strongly related to the identification of those at high risk of sprain and/or the factors that increase risk of ankle sprain.Several extrinsic and intrinsic factors may increase the risk of future sprain. Possible intrinsic factors include postural sway, range of motion, muscle strength, proprioception, and previous sprains. A cursory inspection of the research that has attempted to identify predictors of ankle sprains yields confusing results. 3 For example, Beynnon and colleagues investigated muscle strength in two separate studies and reported an association between low inversion/ eversion ratios and risk of future sprains in one study 4 but not in the other. 5 The same group 5 reported that range of motion was not associated with risk of ankle sprain, but Pope et al 6 found a strong association. Tropp et al 7 found an association between increased postural sway and risk of lateral ankle sprain, but Beynnon et al 5 did not.The aim of this study was to systematically review evidence that measures of voluntary strength, proprioception, range of motion, or postural sway can predict lateral ankle sprain. A secondary aim was to quantify the risk of lateral ankle sprain.
METHODS
Inclusion criteriaStudies were included if they used a longitudinal design and investigated first or recurrent lateral ankle sprain in subjects aged >15 years. To be included in the review, the study must have measured at least one of the following possible intrinsic predictors before monitoring incidence of ankle sprain: range of motion, any measurement of voluntary strength, proprioception, or postural sway. Use of surgical procedures was an exclusion criterion, although clinical trials of surgical interventions that included a group of subjects who had not undergone surgery were included.Identification of studies and assessment of methodological quality Studies were identified through a search of the Medline, Cinahl, Embase and SportDiscus databases from the earliest date to February ...