Effect of unstable shoes on ground reaction force parameters during stance phase of running

Introduction: 24-67% of recreational runners suffer from running-related injuries. The purpose of this study was to test the effect of unstable shoes on selected ground reaction force (GRF) parameters during stance phase of running. Method: 20 healthy men (age of 21±2.27 years, height of 176.93±5.39 cm, and mass of 72.30±8.84 kg) ran on the force plate placed in the middle of 15 m runway in barefoot, with unstable and control shoe conditions. Peak vertical GRF, posterior force, loading rate and impulsive passive force variables were calculated in the three conditions. A repeated measure of ANOVA and Duncan post-hoc tests applied to test the hypothesis (p<0.05). Results: vertical loading rate and vertical peak passive force variables were significantly increased in unstable shoe condition compared to control shoes. In addition, peak posterior force and impulsive passive force variables were significantly increased in unstable shoe compared to control shoe. Conclusion: unstable shoe could increase ground reaction force parameters on foot during running. This finding suggests that unstable shoes could possibly increase risk of running related to injuries.