Resistance Training

Resistance training is a specialized method of conditioning that involves the progressive use of a wide range of resistive loads and a variety of training modalities designed to enhance health, fitness, and sports performance. ^[1] Resistance exercise is the most potent nonpharmacological external stimulus to drive skeletal muscle hypertrophy or to counter disuse-induced muscle loss. ^[2] In order to stimulate further adaptation toward specific training goals, progressive resistance training protocols are necessary. ^[3]

Strength training causes adaptive changes within the nervous system that allow a trainee to more fully activate prime mover muscles and better coordinate their activation, and electromyographic studies show increases in peak force are associated with increased activation of prime mover muscles. ^[4] Resistance training-induced hypertrophy involves enhanced mTORC1 signaling, an expansion in translational capacity through ribosome biogenesis, increased satellite cell abundance and myonuclear accretion, and postexercise elevations in muscle protein synthesis rates. ^[5] When volume load is equal between conditions, the highest loads induce superior dynamic strength gains, whereas muscle hypertrophy is similar irrespective of the magnitude of the load. ^[6]

In older adults, countering muscle disuse through resistance training is a powerful intervention to combat the loss of muscle strength and muscle mass and their debilitating consequences on physical functioning, mobility, independence, and healthy life expectancy. ^[7] Resistance exercise is currently the mainstay of treatment for sarcopenia, the accelerated loss of skeletal muscle mass and function associated with advancing age. ^[8] A meta-analysis found that resistance training significantly improved grip strength, gait speed, and skeletal muscle index in patients with age-related sarcopenia. ^[9] Across the lifespan, resistance training alone was the most effective modality for increasing lean mass compared with no-training controls in individuals with overweight or obesity

Skeletal muscle plays a critical role in physical function and metabolic health, and preserving muscle strength through exercise training can ameliorate metabolic dysfunction and prevent chronic disease. ^{[2] [13]} In community-dwelling older adults, exercise programs focusing on strength can significantly influence muscle mass and muscle strength, minimizing functional decline and risk of falling. ^[14] Dynamic resistance training significantly lowers resting blood pressure, supporting its role in the prevention and treatment of hypertension. ^[15]