Do ankle braces provide similar effects on ankle biomechanical variables in subjects with and without chronic ankle instability during landing?

摘要

Purpose The purpose of this study was to examine effects of a sport version of a semi-rigid ankle brace (Element?) and a soft ankle brace (ASO) on ankle biomechanics and ground reaction forces (GRFs) during a drop landing activity in subjects with chronic ankle instability (CAI) compared to healthy subjects with no history of CAI. Methods Ten healthy subjects and 10 subjects who had multiple ankle sprains participated in the study as the control and unstable subjects, respectively. The CAI subjects were age, body mass index and gender matched with the control subjects. The arch index and ankle functions of the subjects were measured in a subject screening session. During the biomechanical test session, participants performed five trials of drop landing from 0.6?m, wearing no brace (NB), Element? brace and ASO brace. Simultaneous recording of three-dimensional kinematic (240?Hz) and GRF (1200?Hz) data were performed. Results The CAI subjects had lower ankle functional survey scores. The arch index and deformity results showed greater arch deformity of Element? against a static load than in NB and ASO due to greater initial arch position held by the brace. CAI participants had greater eversion velocity than healthy controls. The ASO brace reduced the first peak vertical GRF whereas Element? increased 2nd peak vertical GRF. Element? brace reduced eversion range of motion (ROM) and peak eversion velocity compared to NB and ASO. In addition, Element? reduced dorsiflexion ROM and increased peak plantarflexion moment compared to NB and ASO. Conclusion Results of static arch measurements and dynamic ankle motion suggest that the restrictions offered by both braces are in part due to more dorsiflexed ankle positions at contact, and higher initial arch position and stiffer ankle for Element?.