Effects of Tibiofibular and Ankle Joint Manipulation on Hip Strength and Muscle Activation.

OBJECTIVES: The purpose of this study was to determine whether high-velocity, low-amplitude ankle region manipulations could increase force output and muscle activation of hip musculature in individuals with a history of ankle sprain and unilateral tensor fascia latae (TFL) weakness during muscle testing. METHODS: This investigation used a single-arm repeated measures design. Twenty-five participants' force outputs were tested at three time points (before manipulation, immediately after manipulation, and 48 hours after manipulation), and muscle activation of the rectus femoris, gluteus medius, and TFL was measured before and immediately after manipulation. Manipulations were applied to the talocrural, subtalar, proximal, and distal tibiofibular joints of the weaker limb. No contralateral manipulations were applied. Two-way repeated measures analysis of variance was used to compare maximal and average force production for each limb. In addition, paired t tests were used to compare muscle activation before and after manipulations. RESULTS: There was a significant limb × time interaction. The involved limb average force increased from before manipulation (65.7 N) to 48 hours after manipulation (77.8 N; P = .014), maximal force increased (76.9 N) 48 hours after manipulation (87.8 N; P = .030), and gluteus medius activation increased (9.8% maximum, 12.2% average) immediately after manipulation. No significant differences were found in the uninvolved limb. CONCLUSION: The results of this study suggest that high-velocity, low-amplitude ankle region manipulations might improve hip abductor strength in individuals with a history of ankle sprain and unilateral weakness during a TFL muscle test.