Shields Richard K, Dudley-Javoroski Shauna
Graduate Program in Physical Therapy and Rehabilitation Science, The University of Iowa, Iowa City, IA 52242-1190, USA.
Neurorehabil Neural Repair. 2007 Mar-Apr;21(2):169-79. doi: 10.1177/1545968306293447.
The purpose of this study was to determine whether long-term electrical stimulation training of the paralyzed soleus could change this muscle's physiological properties (torque, fatigue index, potentiation index, torque-time integral) and increase tibia bone mineral density.
Four men with chronic (>2 years) complete spinal cord injury (SCI; American Spinal Injury Association classification A) trained 1 soleus muscle using an isometric plantar flexion electrical stimulation protocol. The untrained limb served as a within-subject control. The protocol involved ~ 30 minutes of training each day, 5 days a week, for a period of 6 to 11 months. Mean compliance over 11 months of training was 91% for 3 subjects. A fourth subject achieved high compliance after only 5 months of training. Mean estimated compressive loads delivered to the tibia were approximately 110% of body weight. Over the 11 months of training, the muscle plantar flexion torque, fatigue index, potentiation index, and torque-time integral were evaluated periodically. Bone mineral density (dual-energy x-ray absorptiometry) was evaluated before and after the training program.
The trained limb fatigue index, potentiation index, and torque-time integral showed rapid and robust training effects (P<.05). Soleus electrical stimulation training yielded no changes to the proximal tibia bone mineral density, as measured by dual-energy x-ray absorptiometry. The subject with low compliance experienced fatigue index and torque-time integral improvements only when his compliance surpassed 80%. In contrast, his potentiation index showed adaptations even when compliance was low.
These findings highlight the persistent adaptive capabilities of chronically paralyzed muscle but suggest that preventing musculoskeletal adaptations after SCI may be more effective than reversing changes in the chronic condition.
本研究旨在确定对瘫痪比目鱼肌进行长期电刺激训练是否会改变该肌肉的生理特性（扭矩、疲劳指数、增强指数、扭矩-时间积分）并增加胫骨骨矿物质密度。
四名患有慢性（>2年）完全性脊髓损伤（SCI；美国脊髓损伤协会分级为A）的男性使用等长跖屈电刺激方案对一侧比目鱼肌进行训练。未训练的肢体作为受试者自身对照。该方案包括每天训练约30分钟，每周5天，持续6至11个月。3名受试者在11个月训练期间的平均依从率为91%。第四名受试者在仅训练5个月后就达到了高依从率。传递到胫骨的平均估计压缩负荷约为体重的110%。在11个月的训练期间，定期评估肌肉的跖屈扭矩、疲劳指数、增强指数和扭矩-时间积分。在训练计划前后评估骨矿物质密度（双能X线吸收法）。
训练肢体的疲劳指数、增强指数和扭矩-时间积分显示出快速而显著的训练效果（P<0.05）。通过双能X线吸收法测量，比目鱼肌电刺激训练未使胫骨近端骨矿物质密度发生变化。依从性低的受试者仅在其依从率超过80%时，疲劳指数和扭矩-时间积分才有改善。相比之下，即使依从性低，其增强指数也显示出适应性变化。
这些发现突出了慢性瘫痪肌肉持续的适应能力，但表明在脊髓损伤后预防肌肉骨骼适应性变化可能比逆转慢性状态下的变化更有效。
