カーフレイズ動作と歩行中の蹴り出しにおける長腓骨筋・後脛骨筋の筋活動の関連

本研究では歩行での蹴り出し動作とカーフレイズ動作について,長腓骨筋,後脛骨筋の筋活動に関連があるかを明らかにすることを目的としている.対象は健常成人23名(男性5名,女性18名,年齢22.1±1.4歳)とし,表面筋電図を用いて歩行時,カーフレイズ動作時の長腓骨筋と後脛骨筋の筋活動を検討した. その結果,長腓骨筋の筋活動,そして長腓骨筋と後脛骨筋の筋活動比について,歩行立脚期蹴り出し直前の足関節底屈動作時とカーフレイズ動作時との間にのみ有意な相関関係が認められた.歩行中の足関節底屈動作時に,長腓骨筋の活動が大きい程,そして後脛骨筋に対する長腓骨筋の活動の割合が大きい対象程,カーフレイズ時においても長腓骨筋の活動が大きく,長腓骨筋の活動の割合が大きい,すなわち優位であることがわかった.このように歩行中の足関節底屈動作とカーフレイズ動作での筋活動に有意な相関が認められたことから,足部への最大荷重点についてもこの二つの動作で関連が予想されるため,今後は足底圧分布についても検討する必要がある.

Ankle plantar flexion movements are involved in raising the heel from the ground during gait and calf-raise. In both movements, the trajectory of the maximum point of planter pressure is especially affected by a balance of the activities of the peroneus longus and tibialis posterior muscles, which control inversion and eversion of the calcaneal bone. This study aimed to clarify the relationship between the activities of the peroneus longus and tibialis posterior muscles in raising the heel from the ground during gait and calf-raise. Subjects (5 male, 18 female, aged 22.1±1.4 years) were examined using surface electromyography during gait and calf-raise, which showed the peroneus longus and tibialis posterior muscle activities and their ratio(the peroneus longus muscle activity/the tibialis posterior muscle activity). We calculated the root mean square during the time that the heel was raised from the ground during gait and calf-raise, and root mean square during gait and calf-raise to standing. The results showed that the peroneus longus muscle activity and the ratio between this and tibialis posterior muscle activity that take place from the time the calcaneal bone leaves the ground to when there is maximum planter pressure at the head of metatarsal bones during gait, correlate with muscle activity and ratio during calf-raise. In other words, the greater the peroneus longus muscle activity, the greater the ratio between it and the tibialis posterior in plantar flexion during gait, and the greater these activities and the ratio in plantar flexion during calf-raising. As a result, it can be considered that the location of the maximum point of planter pressure during gait is related to that during calf-raising. Further research is needed to clarify the relationship between the distribution of planter pressure during the gait, and that during calf-raising.