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

OBJECTIVE: To determine if softshell (AE) and semi-rigid (T1) ankle braces affect lower extremity iEMG activity, force, and jump height during a Vertical Jump Test.

DESIGN: Repeated measures, crossover.

SETTING: Laboratory.

PARTICIPANTS: 42 healthy, active individuals.

OUTCOME MEASURES: Vertical jump height, iEMG activity, peak vGRF.

RESULTS: There 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.

CONCLUSION: Vertical jump height is significantly reduced when wearing ankle braces. Effects on lower extremity iEMG activity are dependent upon brace type.