How can muscle mass be influenced by training or age?

Muscle mass can be significantly influenced by training through resistance exercises, which stimulate muscle hypertrophy and increase strength. Regular strength training, especially with progressive overload, promotes muscle growth regardless of age. Conversely, aging typically leads to a natural decline in muscle mass and strength, known as sarcopenia, due to hormonal changes and decreased physical activity. However, older adults can still increase muscle mass through consistent resistance training, mitigating some effects of aging.