Stokes I A, Moffroid M, Rush S, Haugh L D
Department of Orthopaedics, University of Vermont, Burlington.
Spine (Phila Pa 1976). 1989 Aug;14(8):857-61. doi: 10.1097/00007632-198908000-00015.
Rectus abdominis muscles of young healthy female volunteers were studied to determine both the maximum strength in isometric flexion and the relation between the surface electromyogram (RMS EMG) and torque. Both the upper and lower portions of the abdominal muscle were studied during graded increase and decrease of torque. Repeated testing was performed over 6 weeks. The form of the relation between torque and EMG was better described by a quadratic than by a linear regression relationship, but with considerable variability about the best-fit line. The torque-increasing and torque-decreasing parts of each test were different and were analyzed separately. After 6 weeks of repeated testing, maximum voluntary isometric flexion torque increased 16.8% (P less than 0.01). There was a decrease in the ratio of electromyographic activity to torque production, which was statistically significant in the torque-increasing recordings. These changes in maximum torque and in the EMG-torque relation were attributed to learning through a test-retest effect, rather than to a true change in muscle characteristics. These findings, which show changes in normal subjects undergoing repeated testing, do not support the reliability of isometric strength measurements, or measurements based on RMS EMG recordings, for quantifying abdominal muscle function in patients with back pain, or those undergoing strengthening exercises.
对年轻健康女性志愿者的腹直肌进行了研究，以确定等长收缩屈曲时的最大力量以及表面肌电图（均方根肌电图，RMS EMG）与扭矩之间的关系。在扭矩逐渐增加和降低的过程中，对腹部肌肉的上部和下部都进行了研究。在6周内进行了重复测试。扭矩与肌电图之间关系的形式用二次回归比用线性回归关系能更好地描述，但围绕最佳拟合线存在相当大的变异性。每次测试的扭矩增加部分和扭矩降低部分是不同的，需分别进行分析。经过6周的重复测试后，最大自主等长收缩屈曲扭矩增加了16.8%（P<0.01）。肌电活动与扭矩产生的比值有所下降，在扭矩增加的记录中具有统计学意义。最大扭矩以及肌电图-扭矩关系的这些变化归因于通过重测效应产生的学习，而非肌肉特性的真正改变。这些显示正常受试者在重复测试中发生变化的研究结果，并不支持等长力量测量或基于均方根肌电图记录的测量对于量化背痛患者或进行强化锻炼患者的腹部肌肉功能的可靠性。
