Ankle bracing's effects on lower extremity iEMG activity, force production, and jump height during a Vertical Jump Test: An exploratory study

Abstract

ObjectiveTo determine if softshell (AE) and semi-rigid (T1) ankle braces affect lower extremity iEMG activity, force, and jump height during a Vertical Jump Test. DesignRepeated measures, crossover. SettingLaboratory. Participants42 healthy, active individuals. Outcome measuresVertical jump height, iEMG activity, peak vGRF. ResultsThere was significant change across conditions in lateral gastrocnemius (LG) iEMG activity, F(2,70) = 5.31, p = .007, ηp2 = 0.132, with T1 LG iEMG being significantly less (−2.08(99% CI, −3.98 to 0.18) %MVIC, p = .004) than no brace. Significant changes were seen in rectus femoris (RF) iEMG activity, F(2,68) = 6.36, p = .003, ηp2 = 0.158, with T1 RF iEMG activity being significantly less than AE RF iEMG activity (−2.78(99% CI, −5.36 to −0.19) %MVIC, p = .005). There was a significant change in vertical jump height across conditions, F(2,78) = 22.13, p < .0005, ηp2 = 0.362, with a significant decrease in the AE (−2.41(99% CI, −3.66 to −1.17) cm, p < .0005) and T1 conditions (−2.89(99% CI,−4.56 to −1.23) cm, p < .0005), compared to no brace. ConclusionVertical jump height is significantly reduced when wearing ankle braces. Effects on lower extremity iEMG activity are dependent upon brace type.