Muscle composition, muscle force, velocity, and power to strength training
Changes in muscle composition associated with strength training
Humans change the phenotype of their skeletal muscle in response to exercise, modifying the amount and type of nutrients stored, the quantity and type of metabolic enzymes, the amount of contractile protein, and the stiffness of the connective tissue, to name a few adaptations. The phenotypic shift is caused by the frequency, intensity, and duration of the exercise, as well as the individual's age, genetics, gender, and training history. Even while exercise is frequently referred to as a single stimulus, and we have sought for universal responses, how any individual responds to exercise training will differ based on elements we understand and many more that we do not (Hanson et al., 2009, p.1). Strength training causes changes in the circulatory and musculoskeletal systems, allowing for an increase in overall exercise capacity and performance. Increased mitochondrial biogenesis and capillary density in skeletal muscle aid in the body's ability to transport and utilize oxygen to generate energy, delaying the onset of muscle exhaustion during prolonged aerobic exertion. The cellular electron transport system generates ATP from substrates synthesized in the TCA cycle, and the mitochondrion is the major organelle for energy production. For centuries, the influence of exercise training on muscle phenotype has been recognized. Individuals who exercise for an extended period of time develop superior oxygen delivery to muscles and endurance capacity, but those who operate against a large load generate bigger and stronger muscles. Recent research employing high-intensity short-duration interval training to improve endurance and low-load resistance training to failure to build muscle size and strength has called into question the traditional idea of training specificity.
References:
Hanson, E. D., Srivatsan, S. R., Agrawal, S., Menon, K. S., Delmonico, M. J., Wang, M. Q., & Hurley, B. F. (2009). Effects of strength training on physical function: influence of power, strength, and body composition. Journal of strength and conditioning research, 23(9), 2627–2637. https://doi.org/10.1519/JSC.0b013e3181b2297b
Adaptive responses of muscle force, velocity, and power to strength training.
Sarcopenia is linked to a deterioration in muscle strength, muscle power, muscle quality, and physical function, as well as an increase in fat infiltration and mortality. Power and strength are important indicators of functional ability and impairment. Mobility deficiencies are linked to age-related changes in body composition, muscle mass, and fat infiltration. Strength training is regarded as the best intervention for preventing and treating the undesirable effects of sarcopenia. This conclusion stems from numerous research demonstrating that strength training enhances muscular strength, power, and body composition. Muscle power, muscle strength, and body fat are all predictive of physical function and hinderance, according to some researchers. Leg power, rather than leg strength, appears to explain a bigger amount of the difference in physical function performance in older men and women. Strength alone was a strong predictor of performance in functional activities such as walking and repeated chair stand. Strength training induced gains in power is important predictor of enhanced physical functioning in various tasks. Combinations of these predictors only account for a modest to moderate percentage of the variability in physical function change. These findings show that the effectiveness of strength training in improving functional abilities may be influenced at least in part by the degree to which the strength training program improves power, strength, and body composition.
References:
Hughes, D. C., Ellefsen, S., & Baar, K. (2018). Adaptations to Endurance and Strength Training. Cold Spring Harbor perspectives in medicine, 8(6), a029769. https://doi.org/10.1101/cshperspect.a029769
