View clinical trials related to Disuse Atrophy.
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.
This is a 10-week human study involving 24 younger (20-35 y) and 24 older (65-85 y) healthy individuals. All participants will undergo unilateral immobilization of a knee for 7-10 days, followed by 4 weeks of heavy resistance exercise training (HReT). Half of the participants (12 younger and 12 older) will also undergo 4 weeks HReT prior to the immobilization. Prehabilitative exercise may confer protective effects on subsequent immobilization, and the various underlying mechanisms involved
Episodes of inactivity due to hospitalisation, as short as 5 days, are associated with rapid muscle and strength loss in the elderly. The observed muscle loss with inactivity is likely due to muscle anabolic resistance and increased breakdown rates of muscle tissue. This is of great concern as the average hospital stay in the elderly is 5-6 days. Moreover, minor illnesses not requiring hospitalisation generally require short-term periods of inactive home-based recovery. The accumulation of repeated disuse events in older individuals manifests in a chronic muscle anabolic resistance (i.e. the inability of muscle to respond to anabolic stimuli such as exercise and nutrition) that may underpin the slow but devastating process of age-related muscle loss. It is our belief that strategies to promote muscle health in ageing and reduce healthcare expenditure, should focus on alleviating muscle deterioration and anabolic resistance during short-term disuse. In this regard, we propose that resistance exercise (i.e. weight lifting) performed prior to a disuse event (termed 'prehabilitation') may be sufficient to offset muscle loss in older individuals. Thus, we suggest the potent effect of resistance exercise in older muscles may prevent muscle loss during short-term disuse.
Following orthopedic surgery and/or injury, a significant loss of muscle mass is generally observed. While this loss of muscle mass appears to be the norm, it causes significant problems in both the athletic and general population. Athletes struggle to regain their performance because of the decrease in muscle mass and also have a greater potential for reinjury while they are in a depleted state. In the general population, and particularly among the elderly, this loss in muscle mass can be even more devastating because as people age, it is more difficult to regain muscle after it is lost. In elderly individuals, this loss in muscle mass can lead to significant disability, diminished quality of life along with an increased risk of falls. In addition to the muscle mass lost during the post-operative period, the strength of the muscle also decreases. This has obvious performance implications in athletes, as well as having the potential to extend recovery time. In the elderly, decreased strength may result in reduced independence and inability to perform activities of daily living. Many previous bed rest studies have reported that significant bone loss also occurs during times of decreased mechanical loading. The post-operative period generally results in decreased mechanical loading; however, some muscle loading will still occur during the rehabilitation process. The dynamic relation between muscle activity/loading and bone density changes in the post-operative state has not been fully described and requires further study. With this knowledge of the importance of nutrition to the musculoskeletal system, applying the principles of increased protein intake through the addition of a dietary supplement to a population preparing for orthopedic surgery and subsequent muscle disuse is a logical next step. The investigators hypothesize that through the consumption of a protein-based dietary supplement three times per day (75g protein), along with educating patients on the importance of consuming foods that are high in protein, there will be an attenuation of decreases in muscle mass and strength as well as losses in bone that occur with orthopedic injury and disuse. The investigators long-term goal is to identify a nutritional protocol that can be implemented prior to and following orthopedic surgery to diminish the deleterious effects of the subsequent disuse on muscle and bone.
In the present study, the effects of 7 days of bed rest on muscle mass, muscle fiber characteristics and insulin sensitivity will be determined.
In the present study, the effects of 5 days of lower limb immobilization with or without twice-daily protein supplementation on muscle mass and muscle fiber characteristics will be determined. A young group will be included to compare the changes in muscle mass and muscle fiber characteristics between young and old men.
In the present study, the effects of 5 days of lower limb immobilization with or without daily neuromuscular electrical stimulation on muscle mass and muscle fiber characteristics will be determined.
Leucine supplementation is widely known for promoting strong influence on skeletal muscle remodeling. This study aims to evaluate the effect of leucine supplementation on disuse-induced skeletal muscle atrophy.
Determine the efficacy of neuromuscular electrical stimulation (NMES, Kneehab) in promoting accelerated recovery of quadriceps function in patients recovering from total knee arthroplasty (TKA) as measured by increases in isometric strength of the knee extensors and scores in the Timed Up and Go (TUG) test.