Shields Richard K, Dudley-Javoroski Shauna, Law Laura A Frey
Graduate Program in Physical Therapy and Rehabilitation Science, University of Iowa, Iowa City, IA 52242-1190, USA.
Spine (Phila Pa 1976). 2006 Mar 1;31(5):548-53. doi: 10.1097/01.brs.0000201303.49308.a8.
Longitudinal repeated-measures; within-subject control.
We examined the extent to which an isometric plantar flexion training protocol attenuates bone loss longitudinally after SCI.
After spinal cord injury (SCI), bone mineral density (BMD) of paralyzed extremities rapidly declines, likely because of loss of mechanical loading of bone via muscle contractions.
Six individuals with complete paralysis began a 3-year unilateral plantar flexor muscle activation program within 4.5 months after SCI. The opposite limb served as a control. Compliance with recommended dose was > 80%. Tibia compressive force was > 140% of body weight.
Bilateral hip and untrained tibia BMD declined significantly over the course of the training. Lumbar spine BMD showed minimal change. Percent decline in BMD (from the baseline condition) for the trained tibia (approximately 10%) was significantly less than the untrained tibia (approximately 25%) (P < 0.05). Trained limb percent decline in BMD remained steady over the first 1.5 years of the study (P < 0.05).
Compressive loads of approximately 1 to 2 times body weight, induced by muscle contractions, partially prevent the loss of BMD after SCI. Future studies should establish dose-response curves for attenuation of bone loss after SCI.
纵向重复测量；受试者自身对照。
我们研究了等长跖屈训练方案在脊髓损伤（SCI）后纵向减轻骨质流失的程度。
脊髓损伤（SCI）后，瘫痪肢体的骨矿物质密度（BMD）迅速下降，可能是由于肌肉收缩导致骨骼机械负荷丧失。
6名完全瘫痪个体在SCI后4.5个月内开始了一项为期3年的单侧跖屈肌激活计划。对侧肢体作为对照。对推荐剂量的依从性>80%。胫骨压缩力>体重的140%。
在训练过程中，双侧髋部和未训练的胫骨BMD显著下降。腰椎BMD变化最小。训练侧胫骨BMD（相对于基线状态）的下降百分比（约10%）显著低于未训练侧胫骨（约25%）（P<0.05）。在研究的前1.5年中，训练侧肢体BMD的下降百分比保持稳定（P<0.05）。
由肌肉收缩引起的约1至2倍体重的压缩负荷可部分预防SCI后BMD的丧失。未来的研究应建立SCI后骨质流失减轻的剂量反应曲线。
