Kumar S
Department of Physical Therapy, University of Alberta, Edmonton, Canada.
Ergonomics. 1997 Dec;40(12):1312-34. doi: 10.1080/001401397187397.
Fourteen young male students (mean age 21 years, mean weight 69.4 kg, and mean height 175.4 cm) and 12 young female students (mean age 22.2 years, mean weight 60.6 kg, and mean height 169.3 cm) held 9.07 kg and 6.8 kg, respectively, at their three-quarters horizontal reach distance in upright and stooping postures for a period of 5 min. During these periods the external torque on the lumbosacral disc, intra-abdominal pressure, and electromyographic signals from erectores spinae at T12 and L3 levels, latissimus dorsi and external obliques were recorded at 1 kHz for 2.1 s every 15 s for a period of 5 min. The EMGs were processed in magnitude and time domains to determine muscle fatigue. Through the data obtained it was seen that the intra-abdominal pressure did not follow or reflect either the spinal load or the muscle activity. Based on the arguments presented, it was concluded that the intra-abdominal pressure does not appear to have a role of relieving the spine of some of its load. Instead, it is suggested that it is a dependent variable manifesting itself when mechanisms for spinal stability are evoked to overcome large voluntary and inertial loads.
14名年轻男学生（平均年龄21岁，平均体重69.4千克，平均身高175.4厘米）和12名年轻女学生（平均年龄22.2岁，平均体重60.6千克，平均身高169.3厘米）分别在直立和弯腰姿势下，于身体四分之三水平伸展距离处手持9.07千克和6.8千克重物，持续5分钟。在此期间，每隔15秒以1千赫兹的频率记录2.1秒，共记录5分钟，内容包括腰骶椎间盘的外部扭矩、腹内压以及T12和L3水平竖脊肌、背阔肌和腹外斜肌的肌电信号。对肌电图进行幅度和时域处理以确定肌肉疲劳。通过所获得的数据可以看出，腹内压并未随脊柱负荷或肌肉活动而变化或反映它们。基于上述观点，得出的结论是腹内压似乎并未起到减轻脊柱部分负荷的作用。相反，有人提出腹内压是一个因变量，当引发脊柱稳定机制以克服较大的随意和惯性负荷时它才会显现出来。
