Repeated Ankle Sprains and Delayed Neuromuscular Response: Acceleration Time Parameters

Abstract

Study Design: A comparative study. Objectives: To assess whether in subjects with unilateral chronic ankle instability the dynamic reaction time of the affected ankle differs from the healthy ankle and from ankles of a control group. Background: Reaction time is an essential element in joint protection against sudden unexpected excessive movement requiring fast and coordinated muscle action. During a sudden ankle inversion movement, a reflex action of the evertor muscles is needed to counteract the movement. Adequate neuromuscular response is crucial and a delayed response could contribute to inversion trauma and subsequently to chronic ankle instability. The isokinetic dynamometer acceleration time (ACC-TIME) provides valuable information on dynamic neuromuscular ability. Material and Methods: Patients with unilateral chronic ankle instability (n = 11) and healthy individuals in a control group (n = 11) were tested on an isokinetic dynamometer during 3 sets of 3 reciprocal inversion/eversion movements of both ankles at 30°/s and 120°/s. Analysis of variance models were used to compare the ACC-TIME of the affected ankle to the unaffected ankle of the same subjects and a control group. Results: For the evertor muscles at 30°/s and 120°/s a significantly prolonged ACC-TIME was found when comparing the affected ankles to the contralateral ankles and both ankles of the control group. For the invertor muscles at 120°/s a significantly prolonged ACC-TIME was found when comparing the affected ankle to the unaffected ankles of patients and those of the control group. Conclusions: Because the most important evertor muscles are innervated by the fibular nerve, the significantly prolonged ACC-TIME of the affected ankle is consistent with the finding of a lower motor nerve conduction velocity of the fibular nerve after inversion trauma. The results support the concept of a delayed neuromuscular response as an important factor in the etiology of chronic ankle instability. J Orthop Sports Phys Ther 2006;36:72-79.

The Effect of a 4-Week Comprehensive Rehabilitation Program on Postural Control and Lower Extremity Function in Individuals With Chronic Ankle Instability

“…According to Peters et al, 32 following a lateral ankle sprain, 10% to 30% of individuals report persistent symptoms or reinjury. Those with CAI have been reported to have diminished neuromuscular control, 21,34,39,41 muscle weakness, 44 impaired joint position sense, 27,44 subjective reports of pain, 30,45 recurrent ankle sprains, 1 impaired performance during functional t Study deSign: Prospective, randomized controlled trial.…”

Unloading reactions in functional ankle instability

“…Lateral ankle sprains are common [1], and many individuals will develop functional ankle instability [2] following injury. FAI was described by Freeman [3] as a condition where individuals experience recurrent sprains or a feeling of the ankle ''giving way.''…”

The Effect of the EMG Activity of the Lower Leg with Dynamic Balance of the Recreational Athletes with Functional Ankle Instability

“…The proprioception and feedback mechanisms of the neuromuscular system, which affect ankle instability are important for maintaining functional stabilization of the ankle joint 8) and 66% of people who complained of functional ankle instability after ankle sprain s h o w e d w e a k n e s s o f t h e p e r o n e a l m u s c l e 9 , 1 0 ) . Proprioception deficit and delayed reaction time of peroneal muscle makes postural control difficult with ankle instability 7,11) . Also, a significantly prolonged reaction time of peroneus longus was reported for chronic ankle instability.…”