Development of strength training for the purpose of increasing bone mineral density in the person with spinal cord injury

本研究的目的是制定一套力量训练计划，并为制定有效的运动计划以增加骨密度（BMD）寻求基础数据。使用Cybex II型等速测力仪测量了15例截瘫患者和10例四肢瘫痪患者在60度和180度/性别处的肘关节等速功率。截瘫组（PG）的屈伸力矩明显大于四肢瘫痪组（QG） （p<0.05）。这些结果表明，前臂肌肉在四肢瘫痪患者的肘关节伸展/屈曲动作中起着相对较高的作用。等速峰值扭矩与脊髓损伤水平的关系显示，随着QG水平的升高，扭矩增大，而随着pg水平的升高，扭矩减小。这一趋势表明，脊髓损伤水平较低的截瘫患者在日常生活中除了使用上肢肌肉外，还使用躯干肌肉来驱动扶手椅。从生物力学角度探讨了高强度阻力训练对骨密度的影响。采用双能x线骨密度仪（DEXA）测量了举重运动员和11名对照组的腰椎（L2-4）、股骨近端和全身的骨密度。力量举重组和对照组在腰椎、脊柱和全身骨密度上有显著差异，但在股骨近端骨密度上无显著差异。腰椎骨密度与动力性能之间存在显著相关性。这些结果表明，高强度阻力训练对提高腰椎和全身骨密度是有效的。从生物力学的角度来看，高强度载荷对骨骼施加的压缩应力似乎也能有效地增加骨密度。

The purpose of this study is to develop a strength training program and to seek basic data for development of an effective exercise program to increase bone mineral density (BMD).Isokinetic power of elbow joint in 15 paraplegic and 10 quadriplegic subjects were measured at 60 and 180 degrees/sex by use of the Cybex II isokinetic dynamometers. The extension and flexion torques in paraplegic group (PG) were significantly greater (p<0.05) than those in quadriplegic group (QG). These results indicate that forearm muscles playd a relatively higher role in elbow extension/flexion action in quadriplegic individuals. Regarding the relationship between isokinetic peak torque and spinal cord lesion level, the torque increased with the level in QG,while it decreased in with the level in PG.This tendency indicated that paraplegic individuals with lower spinal cord lesion level are utilized muscles in trunk in addition to those in upper extremities to drive an arm chair in daily life.The effects of high-intensity resistance training on bone mineral density (BMD) were investigated from the biomechanical point of view. BMD of lumber spine (L2-4), proximal femur and whole body was measured using dual-energy x-ray absorptiometry (DEXA) for powerlifters and 11 controls. There were significant differences in lumber spine and whole body BMD between powerlifters and controls, but not in proximal femur BMD.A significant correlation was found between lumbar spine BMD and powerliting performance. These results suggest that high-intensity resistance training is effective in increasing the BMD of lumbar spine and whole body. From a biomechanical standpoint, it appeared that compressive stress exerted on bone by high-intensity loads was also effective in increasing BMD.