Effects of 4 weeks of elastic-resistance training on ankle-evertor strength and latency.

CONTEXT Several researchers have suggested that improving evertor strength and peroneus longus reaction time may help alleviate the symptoms of chronic ankle instability and reduce the rate of recurrent ankle sprains. OBJECTIVES To determine the effectiveness of a 4-wk elastic-resistance exercise-training program on ankleevertor strength and peroneus longus latency in subjects with and without a history of ankle sprains (HAS). DESIGN Randomized controlled clinical trial. PARTICIPANTS 40 subjects (20 male, 20 female; 20 HAS, 20 healthy). Ten subjects (5 male and 5 female) from each of the HAS and healthy groups were randomly assigned to exercise or control groups. INTERVENTIONS 4-directional elastic-resistance exercise training 2 times/wk for 4 wk. MAIN OUTCOME MEASURES Ankle-evertor strength and peroneal muscle latency after sudden inversion were measured before training, after 4 wk of training, and 4 wk posttraining. RESULTS Four weeks of elastic-resistance exercise training did not elicit significant changes in 1-repetition-maximum ankleevertor strength between the exercise and control groups (P = .262), HAS and healthy groups (P = .329), or males and females (P = .927). Elastic-resistance exercise training did not elicit significant changes in peroneus longus muscle latency between the exercise and control groups (P = .102), HAS and healthy groups (P = .996), or males and females (P = .947). CONCLUSIONS The 4-wk elastic-resistance exercise training had no effect on ankle-evertor strength and reflex latency of the peroneus longus after unexpected ankle inversion.