View clinical trials related to Skeletal Muscle Hypertrophy.
Filter by:Skeletal muscle plays a critical role in supporting human health. Beyond its role in providing the force to move, skeletal muscle accounts for a large proportion of metabolic rate, glucose disposal, and amino acid storage. Skeletal muscle is dynamically regulated by environmental stimuli, such as loading (i.e., resistance training]) and unloading (i.e., disuse atrophy) as well as the intake of essential amino acids (EAAs). However, the precise mechanisms that regulate skeletal muscle mass in response to various conditions (e.g., EAA supplementation, resistance training, and unloading) are not completely understood. Therefore, concerted efforts to better understand the mechanisms regulating skeletal muscle size are needed that aid in the development of therapeutic interventions to combat age, disease, and disuse related muscular atrophy.
When you perform weightlifting, your body makes new proteins within your muscle. These new proteins can increase the size of the fibers within your muscle to make your muscle larger, a process called hypertrophy. The common convention surrounding gains in muscle mass and strength are that higher-loads (i.e. heavier weights) used for fewer repetitions are better for increasing strength and lower-loads (i.e. lighter weights) used for higher repetitions are better for increasing muscle mass. However, recent research has found that when higher- and lower-loads are used when participants exercise until volitional fatigue (i.e. cannot perform another repetition), muscle mass and strength increases are similar regardless of using a higher- or lower-load. Many of these studies have examined this effect in males with fewer studies examining the effects of higher- and lower-load training in females when assessing changes in muscle mass, strength, and muscle endurance. Further, it has been shown that there is substantial individual variation in response to resistance exercise training where individuals can be broadly categorized as higher- or lower-responders to resistance exercise training. This study aims to explore how the muscle mass, strength, and muscle endurance of females are impacted by both higher- and lower-loads while also exploring how individuals may respond to the training interventions.
Resistance exercise training is a known stimulant for muscle protein synthesis (MPS) to occur, however the consumption of protein is also necessary to induce a shift towards a positive net protein balance. Other nutrients have been shown to be useful in the accretion of lean body mass and strength. Whey protein has been shown to improve muscle net protein balance after resistance exercise, more so when in conjunction with creatine. Furthermore, essential amino acids such as Leucine have been found to be important in moderating the shift towards a positive net protein balance, especially post-exercise and in combination with whey protein. Other vitamins and minerals have been shown to aid in permitting muscle protein synthesis rather than stimulating it, but are still necessary for optimal gains in hypertrophy. The effect of a multi-ingredient compound has rarely been investigated, and thus this study aims to combine whey protein, leucine, creatine, calcium citrate and vitamin D and test it in a resistance exercise training program over 12 weeks. Another novel aspect in this study will be testing this supplement against a placebo of equal amounts of protein and amino acids, the placebo will contain collagen protein and the non-essential amino acids alanine and glycine. Finally, this study will recruit both men and women (ages 18-30) to determine possible effects of the supplement on muscle hypertrophy in both sexes. We hypothesize that the synergistic effect of the ingredients in our supplement will induce hypertrophy to a larger degree than resistance exercise training with the placebo, and that these benefits will persist in both male and female participants.
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.
When practicing weightlifting regularly the body makes new proteins within the muscle. These new proteins can increase the size of the cells within the muscle to make them larger, a process called hypertrophy. The common convention surrounding gains in skeletal muscle size and strength is that heavy weights are needed. In contrast, lifting lighter weights are thought to be required to induce muscular endurance and not to promote growth. However, it has previously been shown in untrained men that lifting lighter weights results in similar gains in muscle mass and strength as lifting heavier weights. The purpose of this study is to examine how performing resistance training of different intensities (light or heavy weights) affects the degree of muscle growth and strength gain in individuals who are already resistance training. This information will be valuable when designing exercise protocols for increasing muscle size and strength at all ages, or in individuals returning from injury, as a way to stimulate muscle growth and promote strength gains without the need to lift heavy weights.
Rationale: The consumption of dietary protein immediately after exercise is necessary to maximally stimulate muscle protein synthesis rates (24, 37). Recent work suggests that the type of protein consumed (e.g., animal vs. plant-derived proteins) during post-exercise recovery can affect the amplitude of acute increases in muscle protein synthesis rates (25, 31). Specifically, consumption of bovine milk proteins immediately after a single bout of resistance exercise stimulates muscle protein synthesis rates greater than consumption of an isonitrogenous soy-protein beverage (31, 37). Importantly, consumption of milk promotes greater hypertrophy than soy after resistance training (10). Thus, it is generally assumed that the acute muscle protein synthetic response predicts long-term training outcomes, such as hypertrophy. Currently, a great amount of work has been carried out to study the effects of consuming milk proteins on muscle protein synthesis rates after resistance exercise (5, 7, 26, 32). However, very little is known about the effects of other types of high-quality animal proteins, such as beef, on stimulating post-exercise muscle protein synthesis rates. Further describing the muscle protein synthetic response after consumption of other types of high-quality animal proteins will provide valuable information for individuals with milk allergies, lactose intolerance, or simply a strong dislike of dairy products. Objective: To investigate whether the in vivo post-resistance exercise muscle protein synthetic response is augmented when minced beef is ingested as compared to an isonitrogenous-matched milk protein beverage in healthy young men. Study design: Crossover, randomized Study population: 12 healthy young males (18-35 y). Intervention: Subjects will perform resistance exercise and consume either a piece of meat (135 grams, 35 g of protein) or an isonitrogenous-matched milk protein beverage on two separate test days. In addition, continuous intravenous tracer infusions will be applied, with plasma and muscle samples collected. A two week 'wash-out' period will be included between trials. Main study parameters/endpoints Primary endpoint: Muscle protein synthetic rate, expressed as fractional synthetic rate (FSR). Secondary endpoints: Rate of protein digestion and absorption and whole body protein balance.