Bakke M, Thomsen C E, Vilmann A, Soneda K, Farella M, Møller E
Department of Oral Function and Physiology, School of Dentistry, Faculty of Health Sciences, University of Copenhagen, Denmark.
Arch Oral Biol. 1996 Feb;41(2):133-40. doi: 10.1016/0003-9969(95)00135-2.
Work-related fatigue, pain and disorders in skeletal muscles have been related to prolonged static and dynamic activity. Such contractions have been shown to impair blood flow and increase muscle thickness and fluid. In the present study the effect of static and dynamic activity was evaluated from changes in masseter thickness as a measure of oedema, simultaneously with assessment of perceived pain/discomfort and cardiovascular responses. As static activity, fourteen young healthy women bit at 15% maximal voluntary contraction on bite-force transducers in the molar regions until exhaustion or 20 min at maximum (median endurance time 7.1 min). For dynamic activity, the same individuals chewed gum unilaterally until exhaustion or 40 min at maximum (all endured 40 min) with a cycle time of 725 ms, an average load of 9.3% of maximal electromyographic activity (maxEMG) and a peak mean voltage of 54.3% of maxEMG. Muscle thickness was measured by ultrasonography at the mid-portion of the ipsilateral masseter. Immediately after exercise, muscle thickness was significantly increased, more after static (14.0%) than dynamic (8.6%), and returned to pre-exercise values after 20-min recovery. Visual analogue scales (VAS) revealed the concomitant occurrence of pain (static 11.9 VAS%; dynamic 5.9 VAS%), and discomfort (static 8.1 VAS%; dynamic 5.9 VAS%), and both sensations decreased to pre-exercise values after 20-min recovery. Systolic blood pressure increased significantly, more during static (12.5%) than dynamic activity (4.3%), whereas heart rate rose significantly only during dynamic exercise (13.3%). Hence, activity was associated with muscular swelling and pain, and, despite the relatively small size of the masticatory muscles, also with general cardiovascular responses.
与工作相关的疲劳、疼痛和骨骼肌紊乱与长时间的静态和动态活动有关。已表明此类收缩会损害血流并增加肌肉厚度和体液。在本研究中，通过咬肌厚度的变化来评估静态和动态活动的影响，以此作为水肿的指标，同时评估感知到的疼痛/不适以及心血管反应。作为静态活动，14名年轻健康女性在磨牙区的咬力传感器上以最大自主收缩的15%进行咬合，直至力竭或最长20分钟（中位耐力时间7.1分钟）。对于动态活动，相同的个体单侧咀嚼口香糖直至力竭或最长40分钟（所有人都耐受40分钟），周期时间为725毫秒，平均负荷为最大肌电图活动（maxEMG）的9.3%，峰值平均电压为maxEMG的54.3%。通过超声在同侧咬肌中部测量肌肉厚度。运动后立即测量，肌肉厚度显著增加，静态活动后增加更多（14.0%），而动态活动后增加较少（8.6%），且在恢复20分钟后恢复到运动前的值。视觉模拟评分量表（VAS）显示伴随出现疼痛（静态11.9 VAS%；动态5.9 VAS%）和不适（静态8.1 VAS%；动态5.9 VAS%），并且两种感觉在恢复20分钟后均降至运动前的值。收缩压显著升高，静态活动期间升高更多（12.5%），而动态活动期间升高较少（4.3%），而心率仅在动态运动期间显著升高（13.3%）。因此，活动与肌肉肿胀和疼痛有关，并且，尽管咀嚼肌相对较小，但也与一般的心血管反应有关。
