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.
The goal of this clinical trial is to compare the effects of resistance training (RT) preconditioning vs no training on disuse-induced atrophy and post-disuse resistance training in young healthy individuals. The main questions it aims to answer are: - To determine if performing RT prior to a period of disuse enhances the regain of strength, skeletal muscle size, and skeletal muscle quality while performing RT after a period of disuse. - To determine if performing RT prior to a period of disuse dampens the maladaptive effects of disuse on muscle size, muscle quality, and strength. - To determine the anabolic and proteolytic mechanisms underpinning the observed outcomes. Participants will: 1. Perform either 6 weeks of resistance training or maintain an untrained lifestyle 2. Perform 2 weeks of limb immobilization induced disuse of a randomized leg 3. Perform 6 weeks of resistance training Researchers will compare the resistance training preconditioning condition vs the non-trained condition to see if resistance training prior to a period of disuse is beneficial during the disuse period and in the return to training period on skeletal muscle size, strength, and underpinning molecular markers.
Following injury or surgery to a limb, it is often immobilised to allow tissue healing. Short periods of disuse cause loss of muscle size and strength and impaired mechanical properties of tendons, which leads to reduced function. Strategies to combat these deconditioning adaptations include neuromuscular electrical stimulation (NMES), however at present its effectiveness is limited. Recent research suggests that the effects of NMES can be augmented with blood flow restriction (BFR). At present, the effect of combining these two techniques on muscle function during limb immobilisation is unknown. Furthermore, the impact of BFR training during retraining following immobilisation is unknown.
Skeletal muscle plays several different roles in the promotion and maintenance of health and well-being. The loss of muscle mass that occurs with aging, chronic muscle wasting diseases, and physical inactivity puts people at an increased risk of frailty and becoming insulin resistant, and therefore imposes a significant burden on health care spending. Resistance exercise participation has proven particularly effective for increasing muscle mass and strength. This effectiveness can be used by health care practitioners in a rehabilitation setting to promote the recovery of individuals who have undergone involuntary periods of muscular unloading (i.e. limb immobilization caused by a sports injury or reconstructive surgery). However, there is large variability in the amount of muscle mass and strength that people gain following participation in resistance exercise. Some individuals fail to increase the size of their muscle (low responders) whereas others show vary large increases in muscle size (high responders) in response to the same resistance training program. People also show differences in the amount of muscle tissue they lose when they have a limb immobilized. To circumvent variability across individuals, the investigators utilized a within-person paired Hypertrophy and Atrophy ('HYPAT') strategy that reduced response heterogeneity by ~40% (Available at: https://ssrn.com/abstract=3445673). Specifically, one leg performed resistance training for 10 weeks to induce hypertrophy, whereas the other leg underwent single-leg immobilization for 2 weeks to induce atrophy. The primary goal of the study will be to gain insight into the molecular responses to an acute period of single-leg immobilization and resistance exercise (8 days). The investigators will use an integrated systems biology approach to monitor the individual rates of over one hundred different muscle proteins.
In the present study, the investigators will assess the impact of two different feeding patterns (continuous vs intermittent) on insulin sensitivity and muscle mass following bedrest.
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.