Muscle activation following sudden ankle inversion during standing and walking

Abstract

Dynamic response characteristics of ankle musculature following sudden ankle inversion have traditionally been tested in a static, standing position. However, this model does not take into consideration muscle activity and loading characteristics associated with active gait. This study compared muscle reaction times and amplitudes from sudden ankle inversion during standing (standing group) and walking (walking group) using one of two similar devices for each of these conditions. Surface EMG was collected from the peroneus longus (PL), brevis (PB), and tibialis anterior (TA) of the dominant leg from 25 subjects (age 20 +/- 1 years, height 174.0 +/- 10.2 cm, mass 74.3 +/- 12.9 kg) for each condition (walking and standing). Time to total inversion ROM (28 degrees ) was greater in the walking group (114.9 +/- 15.0 ms) than the standing group (65.6 +/- 17.8 ms, P < 0.05), whereas reaction time was less in the peroneals in the walking group (PL 56.9 +/- 8.4 ms, PB 60.1 +/- 10.6 ms, TA 65.0 +/- 14.9 ms) compared to the standing group (PL 74.3 +/- 8.5 ms, PB 73.5 +/- 8.2 ms, TA 73.3 +/- 8.3, P < 0.05). Additionally, Peak normalized EMG (% MVIC) for the walking condition (PL 367 +/- 254, PB 405 +/- 359, TA 84 +/- 39) exceeded that of the standing condition (PL 310 +/- 239, PB 328 +/- 215, TA 76 +/- 39, P < 0.05), and average normalized EMG (% MVIC) was greater in the peroneals for the walking condition (PL 233 +/- 171, PB 280 +/- 255) than the standing condition (PL 164 +/- 131, PB 193 +/- 137, P < 0.05). The differences noted between the conditions provide evidence that a dynamic response to ankle injury mechanisms is much different in a walking model compared to a traditional standing model. A walking model may be a more functional approach for evaluating dynamic response characteristics of ankle musculature due to sudden ankle inversion.

Alterations in evertor/invertor muscle activation and center of pressure trajectory in participants with functional ankle instability

“…Indeed, peroneal dysfunction has been well documented in subjects with ankle instability Konradsen and Ravn, 1991;Palmieri-Smith et al, 2009;Santilli et al, 2005). While the evertors likely do not provide a timely protective contraction to prevent injury during unanticipated foot inversion (Delahunt, 2007;Hopkins et al, 2007;Munn et al, 2010), they do help control foot position during functional movement (Delahunt, 2007;Louwerens et al, 1995). Invertor/evertor coupling during movement facilitates a neutral position, aids in balance, and controls loads during the stance phase of gait (Louwerens et al, 1995;Matsusaka, 1986).…”

Understanding the Effect of High-Cut Shoes, Running Shoes and Prophylactic Supports on Ankle Stability When Performing a “V”-Cut Movement

“…40,41,42 However, Hopkins et al 41 questioned whether the peroneal muscles and the stiffness provided by the contraction would be sufficient to provide stability to the joint during tasks that were more dynamic. The antagonistic muscle activation may therefore not be rapid enough to control the movement during faster movements, contributing to greater risk of injury in the low-cut footwear.…”

Differences in End-Point Force Trajectories Elicited by Electrical Stimulation of Individual Human Calf Muscles

“…Most studies of FIB have used EMG recordings (Forestier & Toschi, 2005; Hopkins et al, 2007) or cadavers (Klein et al, 1996; Kim et al, 2003) and have not focused on FIB as a plantarflexor. While subjects were unconstrained, we observed plantarflexion during electrical stimulation of FIB.…”

“…Another leg muscle, fibularis longus (FIB; peroneus longus is interchangeably used in the literature) is classically described as an evertor during plantarflexion due to its anatomical attachments and EMG based experiments (e.g. Forestier & Toschi, 2005; Hopkins et al, 2007). Much of our information on the individual actions of these muscles comes from cadaver and animal studies which are each limiting in understanding human muscle function.…”