Christensen L V, Mohamed S E, Rugh J D
J Oral Rehabil. 1985 Nov;12(6):509-14. doi: 10.1111/j.1365-2842.1985.tb01298.x.
Three human subjects performed teeth clenching at maximum voluntary contraction strength (MVC) of the mandibular elevator muscles. At intervals of 10s, ten successive bouts of MVC clenching were exercised until total exhaustion of the contracting muscles (isometric endurance). Isometric endurance time decreased exponentially from 59 to 12s. The curve of the decrease showed a monotone power function (y = x-1). Electromyographic recordings from masseter muscles suggested that fatigable motor units, possibly fast glycolytic units, dropped out during the initial stages of maintained MVC isometric activity. The silent period of the monosynaptic jaw jerk reflex was increased by about 35% following exhaustion of the masseter muscle.
三名受试者以最大自主收缩力量（MVC）收缩下颌提升肌进行紧咬牙动作。每隔10秒进行十次连续的最大自主收缩紧咬牙动作，直至收缩肌肉完全疲劳（等长耐力）。等长耐力时间从59秒呈指数下降至12秒。下降曲线呈现单调幂函数（y = x -1）。咬肌的肌电图记录表明，在维持最大自主收缩等长活动的初始阶段，易疲劳的运动单位（可能是快速糖酵解单位）退出活动。咬肌疲劳后，单突触下颌反射的静息期增加了约35%。
