View clinical trials related to Atrophy, Disuse.
Filter by:This study will characterize intramuscular molecular mechanisms underlying anabolic resistance to protein ingestion during muscle disuse. Adults (n=12) will be studied using a unilateral leg immobilization model in which one leg will be randomly assigned to immobilization and the contralateral, active leg used as a within-subjects control. Immobilization will be implemented for five days using a rigid knee brace, during which time participants will ambulate using crutches. Integrated ribonucleic acid (RNA) synthesis will be determined during immobilization in the immobilized and non-immobilized legs using ingested deuterium oxide, salivary and blood sampling, and muscle biopsies. Immediately after immobilization, muscle biopsies will be collected before and 90 mins after consuming 25 g of whey protein from the immobilized and non-immobilized legs to characterize the intramuscular molecular response to protein feeding. Serial blood samples will be collected during that time to characterize the circulating metabolic response to protein ingestion. Knowledge generated from this effort will inform the development of targeted interventions for mitigating anabolic resistance to protein ingestion that develops during periods of muscle disuse.
For many after spinal cord injury (SCI) there is immobilization, muscle atrophy, bone loss, fracture risk during transferring (or falls), and the risk of secondary complications, and increase in attendance care and cost. It is important to develop multi dimensional rehabilitation strategies for people after SCI to enhance functional recovery towards walking, and enhance an increase in muscle and bone to potentially prepare the injured nervous system in the event of a cure. Locomotor training (Stand retraining and step re training) an activity-based rehabilitative approach generates muscle activity and provides weight bearing and joint contact kinetics, even in individuals who are unable to stand or step independently. Cross-sectional animal and human SCI studies have demonstrated that locomotor training (LT) (stand retraining and step retraining using body weight support treadmill training) has improved the capacity to stand independently and walk at faster speeds. Neuromuscular stimulation (NMS) or electrical stimulation (ES) training is a rehabilitative approach that generates muscle activity, alternating leg extension and flexion even in individuals who are unable to stand or step independently. NMS studies for individuals after SCI have shown improvements in bone density and muscle strength after cycling and resistance training. The main purpose of this study is to address whether stand retraining and NMS compared to stand retraining alone or NMS alone will increase neural and musculoskeletal gains and provide a greater functional recovery towards independent standing. This project will be completed at two sites: Kessler Foundation Research Center (the grant PI site) and Frazier Rehabilitation Institute, University of Louisville, Kentucky.