Functional Electrical Stimulation-Assisted Exercise and Bone Health after Spinal Cord Injury

 说明： 日常活动中发生的脆性骨折对许多脊髓损伤(SCI)患者的健康和生活质量产生了负面影响。为了减少脊髓损伤患者脆性骨折的发生率，有必要制定更好的康复策略，以维持骨骼健康。负重于腿部的治疗性运动已显示出调节脊髓损伤后骨丢失的潜力，但一直以来的有益结果尚未得到证实。骨骼力学生物学研究表明，运动过程中骨架力的大小和负荷重复次数是影响骨骼健康的关键参数。然而，在不同类型和强度的康复运动中对肢体施加的机械刺激还没有得到很好的表征。 或比较，使得很难评估它们调节脊髓损伤后骨丢失的相对潜力。拟议的研究的关键目标是评估四种不同的脊髓损伤康复活动中的骨骼负荷，并评估它们对骨骼健康的相对潜力。这项研究的结果有可能影响临床实践，告知临床医生在设计运动方案时，将为下肢提供足够的机械刺激，以利于骨骼健康。关键的目标将通过收集三维运动和力量数据来实现，同时脊髓损伤患者进行四种不同的康复练习，这些运动加载腿部的负荷：1)使用站立框架进行静态负重；2)站立框架治疗配合功能电刺激(FES)；3)FES自行车；以及4)FES划船。将开发两种特定于受试者的肌肉骨骼模型(2D分析模型和3D计算模型)来估计骨骼负荷。肌肉骨骼模型和模拟将被用来计算FES激活的肌力以及在每次康复练习中施加在股骨和胫骨上的骨骼力。练习将根据骨骼力量的大小进行排序。在每一次康复运动中对下肢施加的骨机械刺激将使用典型运动过程中的负荷循环次数和每一次康复活动的平均峰值骨骼力来估计。每项运动保持骨密度的相对潜力将基于机械刺激进行估计。还将计算每项康复运动产生同等骨骼健康潜力所需的运动量。这些结果将为选择最有潜力有益于脊髓损伤后骨骼健康的康复锻炼和活动剂量提供有价值的临床资源。这项研究学习和培训计划还将通过增加临床经验、肌肉骨骼建模方面的高级技术知识、进一步发展临床合作以及将研究成果转化为具有临床意义的应用方面的经验，促进申请者的职业发展。该项目产生的数据将用于设计未来的运动干预研究，以评估当前和新开发的康复方案对脊髓损伤后骨骼健康的影响。此外，为这项研究开发的模型和模拟可用于回答有关设置和使用新的或现有的康复设备或锻炼技术的关键问题，这些设备或锻炼技术可以提高锻炼的有效性。应用这些模型的预测性模拟的结果可以通知医生和治疗师修改(例如，自行车或赛艇运动员的座椅位置，增加重量或阻力等)。这可能会增加或减少骨骼力量，其方式将适合每个患者目前的骨骼状态。这个项目代表了通过开发更好的康复方案来维持脊髓损伤后骨骼健康来降低脆性骨折发生率的最终目标的早期步骤。

 DESCRIPTION: Fragility fractures that occur during everyday activities negatively impact the health and quality of life of many individuals who have a spinal cord injury (SCI). In order to decrease the incidence of fragility fractures in individuals with SCI, there is a need for the development of better rehabilitation strategies targeted at maintaining bone health. Therapeutic exercises that load the lower limbs have shown potential to modulate bone loss after SCI, but consistently beneficial results have not been demonstrated. Bone mechanobiology research indicates that the magnitude of skeletal force and the number of loading repetitions during exercising are key parameters affecting skeletal health. Yet, the mechanical stimulus imposed on the lower limbs during different types and intensities of rehabilitation exercises have not been well characterized or compared, making it difficult to assess their relative potential to modulate bone loss after SCI The key goals of the proposed research are to evaluate skeletal loading during four different SCI rehabilitation activities and to assess their relative potential to benefit skeletal health. Th results of this study have the potential to influence clinical practice by informing clinicians in he design of exercise protocols that will supply the lower limbs with sufficient mechanical stimulus to benefit skeletal health. The key goals will be addressed by collecting three-dimensional motion and force data while individuals with SCI perform four different rehabilitation exercises which load the lower limbs: 1) static weight bearing using a standing frame; 2) standing frame therapy with functional electrical stimulation (FES); 3) FES cycling; and 4) FES rowing. Two types of subject-specific musculoskeletal models (2D analytical models and 3D computational models) will be developed to estimate skeletal loading. Musculoskeletal models and simulations will be used to calculate the FES-activated muscle forces and the skeletal forces applied to the femur and tibia during each rehabilitation exercise. Exercises will be ranked according to the magnitude of skeletal force. The bone mechanical stimulus imposed on the lower limbs during each rehabilitation exercise will be estimated using the number of loading cycles during a typical exercise session and the average peak skeletal forces from each rehabilitation activity. The relative potential of each exercise to preserve bone density will be estimated based on the mechanical stimulus. The exercise dose that would be required for each rehabilitation exercise to produce an equivalent potential for bone health will also be calculated. These results will produce a valuable clinical resource for selecting rehabilitation exercises and activity doses which have the greatest potential to benefit skeletal health after SCI. This research study and training program will also serve to advance the applicant's career development through increased clinical exposure, advanced technical knowledge in musculoskeletal modeling, further development of clinical collaborations, and experience in the translation of research results into clinically meaningful applications. The data generated by this project will be used to design a future exercise intervention study to evaluate the effect of current and newly developed rehabilitation protocols on bone health after SCI. Additionally, the models and simulations developed for this study can be used to answer key questions about the setup and use of new or existing rehabilitation equipment or exercise techniques that could enhance the effectiveness of exercises. Results from predictive simulations that apply these models can inform physicians and therapists of modifications (e.g. cycle or rower seat position, adding weights or resistance, etc.) that could increase or decrease skeletal forces in a way that would be appropriate for each individual patient given their current skeletal status. This project represents an early step towar the ultimate goal of reducing the incidence of fragility fracture by developing better rehabilitatin protocols that can maintain bone health after SCI.