Deficits in peroneal latency and electromechanical delay in patients with functional ankle instability

The purpose of this study was to compare alterations in peroneal latency and electromechanical delay (EMD) following an inversion perturbation during walking in patients with functional ankle instability (FAI) and with a matched control group. Peroneal latency and EMD were measured from 21 patients with unilateral FAI and 21 controls. Latencies were collected during a random inversion perturbation while walking. EMD measures were collected during stance using a percutaneous stimulus. Two-way ANOVAs were used to detect differences between leg (affected, unaffected) and group (FAI, Control). Functionally unstable ankles displayed delayed peroneus longus (PL) latencies and EMD when compared to the unaffected leg and a matched control group. Peroneal latency and EMD deficits could contribute to recurrence of ankle injury in FAI subjects. How these deficits are associated with the chronic symptoms associated with FAI remains unclear, but gamma activation and subsequent muscle spindle sensitivity likely play a role. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:1541–1546, 2009Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/64439/1/20934_ftp.pd

The effect of repetitive ankle perturbations on muscle reaction time and muscle activity

The use of a tilt platform to simulate a lateral ankle sprain and record muscle reaction time is a well-established procedure. However, a potential caveat is that repetitive ankle perturbation may cause a natural attenuation of the reflex latency and amplitude. This is an important area to investigate as many researchers examine the effect of an intervention on muscle reaction time. Muscle reaction time, peak and average amplitude of the peroneus longus and tibialis anterior in response to a simulated lateral ankle sprain (combined inversion and plantar flexion movement) were calculated in twenty-two physically active participants. The 40 perturbations were divided into 4 even groups of 10 dominant limb perturbations. Within-participants repeated measures analysis of variance (ANOVA) tests were conducted to assess the effect of habituation over time for each variable. There was a significant reduction in the peroneus longus average amplitude between the aggregated first and last 10 consecutive ankle perturbations (F = 3.90, P = 0.03, ɳ  = 0.16). Authors should implement no more than a maximum of 30 consecutive ankle perturbations (inclusive of practice perturbations) in future protocols simulating a lateral ankle sprain in an effort to avoid significant attenuation of muscle activity

The role of ankle bracing in injury prevention, athletic performance and neuromuscular control: a review of the literature

Ankle bracing is widely used by sports participants in order to prevent lateral ankle sprains. Current evidence on the various effects of ankle orthoses reveals that not only they are effective in minimizing the risk of injury, but also they do not hinder athletic performance and other parameters related to function. This review attempts to present all currently existing evidence regarding the effects of protective ankle braces and even more importantly, to discuss issues that have not been adequately investigated and identify areas for future researc