頭位の変化が咀嚼筋の随意収縮活動に及ぼす影響について

概要

論文の詳細を見る
Effects of head positions on the activity of massetcer and temporal muscles during volruntary contractioua were evaluated on six subjects with norraal jaw-function. The subjects in the upright body position were asked to perform maximum voluntary contractions in three head positions ; full dorsal flexion, full ventral flexion, and normal head position. EMG recordings of the muscles as myoelectrical activity and bite force as myomechanical activity were taken simultaneously. Acquired data were analyzed by four parameters ; 1) integrated EMG, 2) bite force, 3) median frequency of EMG power spectra, and 4) EMG/force ratio. Integrated EMG of masseter muscle in the dorsal flexion increased in activity by 30% over the normal position and decreased in the ventral flexion. On the contrary, bite force was not influenced by head positions, thus resultant EMG/force ratio c:hanged in the same manner as integrated EMG did. These effects of head positions were greater in the masseter than in the temporal muscle. No evidences of muscular fatigue such as contractile failure, increasing EMG/force ratio, or spectral shift to lower frequency in the normal head position were observed in the study. These results suggest that changing laead position generates antagonistic or synergistic force to masticatory contraction force.
日本補綴歯科学会の論文
1991-02-01