横足根関節回内可動性が片脚立位時の骨盤運動と中殿筋筋活動に及ぼす影響について

抄録

The purpose of this study was to investigate whether ROM on pronation of the transverse tarsal joint affected both pelvic movement and EMG activity of gluteus medius muscle on hemi-standing. We researched two experiments about ROM limitation on pronation of the transverse tarsal joint. One was the inherent limitation: it was classified as the hypo-mobility side (ROM on pronation of the transverse tarsal joint <10°) or normal-mobility side (ROM on pronation of the transverse tarsal joint ≥10). Another was artificial limitation by meanes of taping. It discriminated between the non-taping group and the taping group (ROM on pronation of the transverse tarsal joint=0°). In each experiment, subjects were instructed to maintain hemi-standing with 90 degree hip flexion on the unsupported side. We compared the degree of eversion of the subtalar joint, pelvic movement and EMG activity of the gluteus medius muscle on the supported side on hemi-standing on both the hypo-mobility side and the normal-mobility side; and taping group and non-taping group in two experiments, respectively. In both of the two experiments on ROM limitation on pronation ofthe transverse tarsal joint, pelvic movement tended to increase pelvic elevating to the opposite side on hemi-standing or the degree of eversion of the subtalar joint on the supported side significantly increased on hemi-standing, and EMG activity of the gluteus medius muscle significantly increased on hemi-standing. We would like to emphasize that pelvic movement was altered by ROM limitation on pronation of the transverse tarsal joint. The main reason was that ROM limitation on pronation of the transverse tarsal joint on the supported side caused excessive eversion of the subtalar joint on hemi-standing. And excessive eversion of the subtalar joint caused the obstruction to shift the pelvis in the direction of the supported side for hemi-standing. We suggest that the pelvic elevation to the opposite side was caused to compensate for obstruction when shifting the pelvis in the direction of the supported side.