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

Abstract

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. ß

Muscle Latency and Proprioception in Non-Dominant and Dominant Legs of Healthy Sedentary Individuals

“…The present study exhibited partially consistent results with the previous studies for reaction times for the peroneal and tibialis anterior muscles (10,(28)(29)(30)(31). In this study, the mean peroneal latencies ranged from 88 to 102 msec and 86 to 91 msec in the non-dominant and dominant limbs, respectively.…”

“…In this study, the mean peroneal latencies ranged from 88 to 102 msec and 86 to 91 msec in the non-dominant and dominant limbs, respectively. Although shorter peroneal reaction times (50-66 msec) in healthy ankles compared to our results were stated in a majority of the previous studies (10,28,31,32), the results of other studies (29,30) were quite comparable with our results. The mean anterior tibial latencies ranged from 95 to 105 msec and 90 to 101 msec in the non-dominant and dominant limbs, respectively.…”

Foot Structure and Muscle Reaction Time to a Simulated Ankle Sprain

“…We did not identify differences in gluteus medius reaction time, possibly because the perturbation caused by the static (standing) tilt platform could be corrected by ankle strategy alone in all groups. It would be interesting to observe the reaction times of the gluteus medius in people with different foot structures during a more demanding task, such as using a dynamic (walking) tilt platform as described by Hopkins et al 16,17 or during a perturbed dynamic landing task as described by Gutierrez and Kaminski. 31 We did not identify differences among foot structures for the tibialis anterior, indicating that foot structure does not affect the function of this muscle during an inversion and plantar-flexion simulation.…”

“…In some studies, 13,34 these variables are not reported, making comparisons difficult; however, the most widely reported value is the number of standard deviations above the baseline measure. This number has varied enormously, ranging from 2 SDs 33,35 to 3, 17 5, 36 and 10 SDs 37 above the baseline measure. Few authors have justified the variables chosen; however, Hodges and Bui 38 advised that the standard deviation must be high enough to avoid a type I error, where the muscle is identified as active when it is not, yet low enough to avoid a type II error, where the researcher does not identify the EMG onset when it occurs.…”

“…[11][12][13][14][15] Using a static (standing) platform [11][12][13][14][15] or a dynamic (walking) platform, 16,17 it is designed to simulate the mechanics of an inversion ankle sprain, therefore stressing the dynamic defense mechanism. 11 Typically, electromyographic (EMG) measurements include the peroneus longus [11][12][13][14] and the tibialis anterior 11 because these muscles have direct roles in the dynamic defense mechanism.…”