EXTENDED ACTIVITY EFFECT ON THE PERFORMANCE OF ANKLE SUPPORT DEVICES AS REFLECTED BY RANGE OF MOTION. AND Ground Reaction Forces

Abstract

Various techniques and devices are used to offer support to one of the most common injuries seen in sports, that of the ankle sprain, particularly the inversion type (Garrick & Requa,1988; and Lane 1990). Such techniques included the use of a cloth ankle wrap, elastic and/r non-elastic tape, and recently as an alternative commercially available ankle braces. The cumulative information on the effects of taped and various types of braced ankle support is inconclusive. This is mainly because most of the studies done have had data collected, soon after the support conditions were administered. Such injuries commonly occur during landing. The purpose of the present project was to study the changes on plantardorsiflexion and inversion-eversion ranges of motion as well as on selected vertical ground reaction force variables (using a standardized drop task) for different supporting devices at different points oftime over a sixty minute activity period. Thirty subjects were tested under conditions of unsupported, nonelastic adhesive taped, Swede-0, and Sub Talar Support braced ankles. Measurements were taken during unsupported pre-activity, and after 0,15, 30, 45, and 60 minutes of selected activity on a treadmill. The range of motion changes, at the above times, were recorded on a modified Inman Ankle machine. The standardized drop task was performed from a suspended position with the aid of an adjustable height apparatus, easily modified for each subject's height, positioning the lateral malleolus at a 60 cm height from the AMTI force plate before each drop. All support conditions compared to unsupported ankles significantly reduced preactivity range of motion in all directions. Plantarflexion range of motion increased significantly after 15 min of activity in taped and SubTalar supported ankles, and after 30 min for the Swede-0. All three support conditions significantly increased in inversion range of motion, from 0 to 15 min of activity. A double peak pattern of the vertical ground reaction force was evident across ankle support techniques and activity conditions. Changes to the peaks due to activity where consistent both in magnitude and timing across subjects for the taped and the Swede- 0 braced ankles. The peaks were higher and appeared earlier for the supported ankles before and after the activity, as compared to the unsupported conditions, These results indicate that both the tape and the Swede-0 brace alter the dynamic characteristics of the ankle joint.