Effects of Joint Mobilization on Foot Pressure, Ankle Moment, and Vertical Ground Reaction Force in Subjects with Ankle Instability

Objective: The purpose of this study was to investigate the effects of joint mobilization on foot pressure,ankle moment, and vertical ground reaction force in subjects with ankle instability.Method: Twenty male subjects (age, 25.38 ± 3.62 yr; height, 170.92 ± 5.41 cm; weight, 60.74 ± 9.63 kg;body mass index (BMI), 19.20 ± 1.67 kg/m2) participated and underwent ankle joint mobilization. Weightbearingdistribution, ankle dorsi/plantar flexion moment, and vertical ground reaction force were measuredusing a GPS 400 and a VICON Motion System (Oxford, UK), and subsequently analyzed. SPSS 20.0 forWindows was used for data processing and paired t-tests were used to compare pre- and post-mobilizationmeasurements. The significance level was set at α = .05.Results: The results indicated changes in weight-bearing, ankle dorsi/plantar flexion moment, and verticalground reaction force. The findings showed changes in weight-bearing distribution on the left (pre 29.51± 6.31 kg, post 29.57 ± 5.02 kg) and right foot (pre 32.40 ± 6.30 kg, post 31.18 ± 5.47 kg). There weresignificant differences in dorsi/plantar flexion moment (p < .01), and there were significant increases invertical ground reaction forces at initial stance (Fz1) and terminal stance (Fz2, p < .05). Additionally, therewas a significant reduction in vertical ground reaction force at midstance (Fz2, p < .001).Conclusion: Joint mobilization appears to alter weight-bearing distribution in subjects with ankle instability,with resultant improvements in stability.