Dynamic force distribution during level walking under the feet of patients with chronic ankle instability

Abstract

Objectives: To examine changes in the pattern of force transfer between the foot and the floor associated with chronically sprained ankles by measuring the peak forces and their timing under several regions of the feet during level walking. Methods: Twelve young male subjects (mean (SD) age 21 (2) years) with recurrent ankle sprains were studied. Seven of them had unilateral and bilateral chronic instability and laxity, and five had bilateral instability. Twelve healthy men (without orthopaedic or medical disease) served as a control group. Subjects walked at their own pace along a 7 m walkway, which included a Mini-EMED pressure distribution measuring system. The variables measured were relative peak force (fraction of body weight) and relative timing (fraction of stance time). These variables were measured under six regions of interest in each foot print: heel, midfoot, medial, central, and lateral forefoot, and toes. Results: (a) A significant delay to the time of peak force under the central and lateral forefoot and toes in subjects with chronic ankle instability. (b) A significant decrease in the relative forces under the heel and toes and an increase in the relative forces under the midfoot and lateral forefoot in subjects with chronic ankle instability. (c) In the patients with unilateral instability, there were no significant differences in any of the variables between the injured and non-injured foot. Conclusions: In patients with chronic ankle instability, there is a slowing down of weight transfer from heel strike to toe off, a reduced impact at the beginning and end of the stance phase, and a lateral shift of body weight.A nkle sprain is the most common injury in athletes and people participating in sport, representing 15-20% of all sport injuries.1 In soccer and basketball, the risk of ankle sprain is even higher, being 45% and 31% respectively.

Is there “arthrogenic inhibition” of cutaneous reflexes in subjects with functional ankle instability?

“…Using an in-shoe plantar pressure system, Schmidt et al (2011) showed that ankle instability subjects had greater plantar pressures and forces in the lateral foot compared to controls. Similar abnormalities were described by Nyska et al (2003). One remarkable finding was that the patients with unilateral instability showed no significant differences in any of the variables measured between the injured and non-injured foot.…”

Altered Vertical Ground Reaction Forces in Participants With Chronic Ankle Instability While Running

“…Through various portions of the gait cycle, people with CAI walk and run with altered ankle and foot kinematics compared with uninjured people. 4 In walking, kinetic differences include greater peak plantar pressure in the midfoot and lateral forefoot, 5 a laterally deviated center of pressure (COP), 6 and increased braking and propulsive forces 7 compared with uninjured participants. While running, individuals with CAI have increased pressure within the lateral rear foot and a lateral COP trajectory compared with a medial COP trajectory in healthy individuals during the loading response phase.…”

Balance Training and Center-of-Pressure Location in Participants With Chronic Ankle Instability

“…27 Plantar-pressure studies have also demonstrated increased force and pressure concentration under the lateral midfoot and forefoot in participants with CAI during gait, which supports the notion of an anterior and lateral COP shift. [29][30][31] Balance-training programs have been effective in improving postural control in participants with CAI. 28,[32][33][34][35][36][37] McKeon et al 28 showed static and dynamic postural-control improvements in a sample of participants with CAI after 4 weeks of balance training that was intended to challenge their sensorimotor systems.…”