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

采用Cybex II等速测力仪，对15例截瘫患者和10例四肢瘫痪患者在60度/性别和180度/性别条件下的肘关节等速力量进行了测量，旨在制定力量训练方案，为制定有效的运动方案提供基础数据。截瘫组(PG)的屈伸扭矩明显大于四肢瘫痪组(QG)(P&lt；0.05)。这些结果表明，前臂肌肉在四肢瘫痪患者的伸肘/屈肘动作中发挥着相对较高的作用。在等速峰力矩与脊髓损伤平面的关系上，扭矩随着QG水平的升高而增大，随着PG水平的升高而减小。这一趋势表明，日常生活中，脊髓损伤平面较低的截瘫患者除利用上肢肌肉外，还利用躯干肌肉来驱动臂椅。从生物力学的角度研究了大强度阻力训练对骨密度的影响。采用双能X线骨密度仪(DEXA)对举重运动员和11名对照组的腰椎(L2-4)、股骨近端和全身骨密度进行测量。举重运动员腰椎和全身骨密度与对照组有显著差异，而股骨近端骨密度无显著差异。腰椎骨密度与力量训练成绩显著相关。提示大强度抗阻训练能有效提高腰椎和全身骨密度。从生物力学的角度来看，高强度载荷施加在骨上的压应力似乎也有效地增加了骨密度。

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.