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

Purpose:The purpose of this study was to examine effects of a sport version of a semi-rigid ankle brace (ElementTM) 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),ElementTM 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 ElementTM 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 coutrols.The ASO brace reduced the first peak vertical GRF whereas ElementTM increased 2nd peak vertical GRF.ElementTM brace reduced eversion range of motion (ROM) and peak eversion velocity compared to NB and ASO.In addition,ElementTM 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 ElementTM.

Ankle and foot mechanics in individuals with chronic ankle instability during shod walking and barefoot walking:A cross-sectional study

Purpose:This study evaluated the angular kinematic and moment of the ankle and foot during shod walking and barefoot walking in individuals with unilateral chronic ankle instability(CAI).Methods:Recreational soccer players with unilateral CAI were recruited for this cross sectional study conducted between January and August 2019.A total of 40 participants were screened for eligibility but only 31 met the inclusion criteria based on the methods of Delahunt et al and Gribble et al.Except for 3 participants not attending the evaluation session,28 participants were finally included.A three dimensional motion analysis system made up of ProReflex motion capture unit and an AMTIb Kistler force plate,embedded in the middle of nine meter walkway,were used to assess the ankle and foot angles and moment during shod walking and barefoot walking conditions.A Statistical Package for Social Sciences(version 20.0)was used to analyze data.Results:During shod walking,the ankle joint plantar-flexion range of motion(ROM)at 10%of the gait cycle(GC)and dorsiflexion ROM at 30%of the GC were significantly higher than those during barefoot walking for both feet(p=0.001,0.001,0.027,and 0.036 respectively).The inversion ROM during shod walking was significantly higher than that during barefoot walking for both feet at 10%and 30%of the GC(p=0.001.0.001,0.001,and 0.042 respectively).At 10%of the GC,the eversion moment was significantly higher between barefoot and shod walking for both feet(both p=0.001).At 30%of the GC,there was no significant difference between shod and barefoot walking plantar-flexion moment of both feet(p=0.975 and 0.763 respectively),and the eversion moment of both feet(p=0.116 and 0.101 respectively).Conclusion:At the early stance,shod walking increases the ankle plantar-flexion and foot inversion ROM,and decreases the eversion moment for both feet in subjects with unilateral CAI.Therefore,the foot wearing condition should be considered during evaluation of ankle and foot kinematics and kinetics.