Ischemic Preconditioning to Augment muscle Function in Individuals with Spinal Cord Injuries

脊髓损伤(Sci)通常导致久坐不动的生活方式和严重的病情解除。 锻炼的选择有限。这种减少的体力活动通常会导致体重增加， 骨质流失，肌肉萎缩，循环不良，心血管功能受损 抑郁和自信心下降。锻炼水平以下肌肉的选择 仅限于电刺激驱动的运动，被限制为减少 肌肉力量和功输出。这最终会导致心肺、新陈代谢减少 健全人的肌肉适应性与意志性运动干预的比较 个人。因此，一种可以增加肌肉力量和作功的干预 在电刺激(ES)运动中进行锻炼对个人来说是非常重要的 脊髓损伤可以改善腿部肌肉质量的维持，更好 生理适应和生活质量的提高。缺血预适应(IPC)包括 在运动前进行短暂的缺血和再灌流。大体上 在人群中，IPC显示出积极的肌肉益处，如增加有氧和 无氧运动表现，延长骨骼肌疲劳时间并提高 从最大的努力中恢复。然而，这一前景看好的干预措施尚未得到检验 在患有脊髓损伤的人中进行ES锻炼。因此，该尖顶提案的目的是确定IPC是否 运动前使用ES是安全的，可以改善骨骼肌功能和耐力 老兵有完全的脊髓损伤。20名受试者将被招募参加一项由5个疗程组成的研究 这将包括在ES隔离肌肉收缩或ES降低之前进行IPC或假手术 身体锻炼。具体目标1将决定进行一场急性IPC的安全性 在进行膝关节伸展之前，如果最大的肌肉力量和抗疲劳能力 (Biodex等速测力仪)在IPC后有所改善。此外，组织氧合，股骨 将评估血流和血乳酸，以确定IPC对组织的潜在影响 灌流和血管功能。具体目标2将决定是否执行急性 在ES自行车练习(骑卧式三轮车骑自行车)之前的IPC比赛将会有所改善 性能包括功率输出和循环时间/距离。股骨组织氧合 血流量和血乳酸也将在这些会议期间收集。最终，如果一个急性 IPC是安全的，并在ES运动中增强肌肉性能，进一步研究 确定慢性ES运动结合IPC的长期生理益处 都是有根据的。IPC有可能提高目前的康复标准 患有SCI的退伍军人。此外，能够增加运动强度和骑自行车 表现有可能为退伍军人提供SCI额外的肌肉力量 需要在地面上和社区内骑着改装的ES三轮车。

Spinal cord injury (SCI) often results in a sedentary lifestyle and profound deconditioning due to limited options for exercise. This decreased physical activity often leads to weight gain, bone loss, muscle atrophy, poor circulation, impaired cardiovascular function along with depression and decreased self-confidence. Options to exercise the muscles below the level of injury are restricted to electrical stimulation driven exercise that is constrained to reduced muscular force and work output. This ultimately results in reduced cardiorespiratory, metabolic and muscular adaptations compared to volitional exercise interventions in able bodied individuals. For this reason, an intervention that can increase the muscular force and work performed during electrical stimulation (ES) exercise is of utmost importance for individuals with SCI as it can lead to improved maintenance of lower limb muscle mass, better physiological adaptations and improved quality of life. Ischemic preconditioning (IPC) consists of brief periods of ischemia followed by reperfusion performed prior to exercise. In the general population, IPC has shown positive muscular benefits such as increased aerobic and anaerobic exercise performance, prolonging the time to skeletal muscle fatigue and improved recovery from maximal effort. However, this promising intervention has yet to be tested with ES exercise in those with SCI. Thus, the purpose of this SPiRE proposal is to determine if IPC prior to exercise with ES is safe and can improve skeletal muscle function and endurance in Veteran’s with complete SCI. 20 subjects will be recruited for a study consisting of 5 sessions that will involve performing IPC or a sham prior to ES isolated muscle contractions or ES lower body exercise. Specific Aim 1 will determine the safety of performing an acute bout of IPC prior to performing knee extension and if maximal muscle strength and fatigue resistance (Biodex isokinetic dynamometer) improves after IPC. In addition, tissue oxygenation, femoral blood flow and blood lactate will be assessed to identify potential impact of IPC on tissue perfusion and vascular function. Specific Aim 2 will determine whether performing an acute bout of IPC prior to ES cycling exercise (cycling on a recumbent tricycle) will improve performance including power output and time/distance cycled. Tissue oxygenation, femoral blood flow and blood lactate will also be collected during these sessions. Ultimately, if an acute bout of IPC is safe and augments muscle performance during ES exercise, further studies to determine long-term physiological benefits of chronic ES exercise in combination with IPC would be warranted. IPC has the potential to enhance the current rehabilitation standards for Veterans with SCI. In addition the ability to increase exercise intensity and cycling performance has potential to provide Veterans with SCI the additional muscle strength required to cycle overground and in the community on modified trikes with ES.