Madeleine P, Voigt M, Arendt-Nielsen L
Center for Sensory-Motor Interaction, Aalborg University, Aalborg East, Denmark.
Eur J Appl Physiol Occup Physiol. 1998;77(1-2):1-9. doi: 10.1007/s004210050292.
The aim of this laboratory study was to examine the subjective, physiological and biomechanical responses to prolonged light repetitive manual work during standing on soft (polyurethane standard mat) and hard (aluminum casting) surfaces. The subjects stood on the hard (10 subjects) and on the soft surfaces (11 subjects) for 2 h. Intensity of unpleasantness, shank circumference, electromyograph (EMG) activities from the right soleus and tibialis anterior muscles, mean amplitude and total angular displacement around the left and right ankle in the saggital plane, centre of pressure (CoP) displacement in the frontal and saggital planes, calf surface temperature, and pain intensity in experimentally induced muscle pain were recorded. Maximal voluntary contraction and fatigue tests were performed before and after the 2 h experiment. Standing on a soft surface caused a lower intensity of unpleasantness. During standing on a hard surface compared to a soft one the results showed an enhanced swelling of the shank, an increased EMG activity (right soleus muscle) of the lower leg, a greater amplitude and total angular displacement, and a larger CoP displacement in the frontal plane. Indications of more pronounced muscle fatigue while standing on the hard surface were also noticed. After 105 min, experimental muscle pain was elicited by injecting hypertonic saline. The intensity of the induced pain was lower when standing on the soft surface. Amplitude, angular distance and CoP displacement showed a tendency to be greater after injection of the hypertonic saline. It was found that the experimentally induced pain influenced postural activity, underlining central interactions between proprioceptors and nociceptors. The results highlighted a higher feeling of comfort when standing on the soft surface. In addition, postural activity was lower when standing on the soft surface, but the activity was sufficient to prevent swelling of the lower legs.
本实验室研究的目的是，考察在软质（聚氨酯标准垫）和硬质（铝铸件）表面站立时，长时间进行轻度重复性体力劳动所产生的主观、生理和生物力学反应。受试者分别在硬质表面（10名受试者）和软质表面（11名受试者）站立2小时。记录不适感强度、小腿围度、右侧比目鱼肌和胫骨前肌的肌电图（EMG）活动、矢状面左右踝关节周围的平均幅度和总角位移、额状面和矢状面的压力中心（CoP）位移、小腿表面温度，以及实验性诱发肌肉疼痛时的疼痛强度。在2小时实验前后进行最大自主收缩和疲劳测试。站在软质表面时不适感强度较低。与软质表面相比，站在硬质表面时，结果显示小腿肿胀加剧、小腿肌电图活动（右侧比目鱼肌）增加、幅度和总角位移更大，以及额状面的压力中心位移更大。同时也注意到，站在硬质表面时肌肉疲劳更为明显的迹象。105分钟后，通过注射高渗盐水诱发实验性肌肉疼痛。站在软质表面时诱发疼痛的强度较低。注射高渗盐水后，幅度、角距离和压力中心位移呈现增大的趋势。研究发现，实验性诱发的疼痛会影响姿势活动，这突出了本体感受器和伤害感受器之间的中枢相互作用。结果表明，站在软质表面时舒适度更高。此外，站在软质表面时姿势活动较少，但该活动足以防止小腿肿胀。
