Influence of Hip Joint Range of Motion on Postural Stability in Trampoline Gymnasts

Author(s): Mutsumi Takahashi, Yogetsu Bando, Takuya Fukui.

The aim of this study was to examine the effect of hip joint range of motion on dynamic stability, including the effect of occlusion. Participants were 13 male trampoline gymnasts. Spinal curvature was measured for each participant in the standing upright position, standing forward flexed, and standing extended positions using a spinal column shape analyzer, and the software calculated hip joint range of motion. Dynamic stability was evaluated by performing a cross-test with a center-of-gravity sway meter. The rectangular area obtained from the product of the longitudinal and transverse moving distances of the center of foot pressure in the center-of-gravity movement trajectory diagram was used as an index of dynamic stability. Measurements were performed under three conditions: mandibular rest position (RP), occlusion in intercuspal position (OP), and occlusion when wearing a mouthguard (MG). The hip joint range of motion or rectangular area under different occlusal conditions was compared using repeated measures ANOVA. Under each occlusal condition, Pearson’s product–moment correlation coefficient was used to analyze the correlation between two variables. The hip joint range of motion and rectangular area were lowest in the OP, with significant differences observed between OP and RP and between OP and MG (P<0.05). A positive correlation was found between the two under all conditions (P<0.05). This study suggested that greater hip joint range of motion was associated with greater dynamic stability. Furthermore, it suggests that hip joint range of motion may be influenced by the balance of occlusal contacts.