高齢者における太極拳八段錦運動前の大腿四頭筋群振動刺激が心拍反応に及ぼす影響

The Effect on Heart Rate with Local Vibration of the Quadriceps Femoris before Hachidan-nishiki(Eight Movements of Tai Chi) Exercise in Aged People

要旨　本研究の目的は低強度運動実施前の大腿四頭筋群への振動刺激が脚筋力に及ぼす影響について心拍反応の変化から検討することである．方法は，都内在住の65～80歳までのボランティア12人(振動刺激群7人，対照群5人)に1カ月間週3回，太極拳八段錦(約20分)のビデオを見ながら自宅で実施した．運動前に振動刺激(60Hz)を大腿部前面に5秒間隔，左右交互に各脚12回反復し与えた．その結果，1カ月後の脚筋力と心拍数は振動刺激群では有意に増加したが，対照群では有意な差がなかった．また，RRIの周波数分析において，HF/T比は両群ともにトレーニング後は上昇傾向を示した．八段錦運動時の呼吸反応は副交感神経活動に影響を与えた．以上の結果から，運動開始前の動作筋への振動刺激は仮想的運動感覚を惹起させることにより，運動に見合った循環応答や低強度の運動に対しても筋力の改善を引き出すことに有用な方法であることが示唆された．

　The purpose of this study was to examine the responses in heart rate(HR) during Hachidan-nishiki(H-n) exercise with vibration stimulation of the active muscles before the exercise. Methods: Twelve healthy volunteers〔vibration group(VG)＝7, control group(CG)＝5〕 were recruited. Subjects were 65-80-year-old men and women living in Tokyo. Subjects performed H-n exercise for about 20 minutes while watching an instruction video. The exercise was performed three times per week for one month at home. The frequency of vibration was 60 Hz before the exercise for five seconds, repeated 12 times on the quadriceps femoris(QF) of the right and left legs, alternately.

　Results: In VG(age＝70.7±4.8, BMI＝24.7±2.4) both strength of knee extension and HR during exercise significantly increased(p＜0.05) after training. In CG(age＝70.2±4.3, BMI＝24.5±5.6) there was no change. On the other hand,in frequency analysis of RRI, the HF/T ratio tended to increase in both groups after training. This indicates that H-n exercise stimulates parasympathetic activity. Conclusion: These results suggest that optimum cardiovascular response and the improvement of leg strength occur with H-n exercise training in aged people. Stimulation of the active muscle with vibration before exercise elicits afferent effects on the autonomic nervous system. Therefore, vibration stimulation of the QF before exercise is recommended as a highly effective method even for low level exercise.