A common goal for strength-training programs is to increase or to maintain one’s physical strength or muscle mass. In order to achieve more strength, as opposed to maintaining current strength capacity, muscles (see skeletal muscles) need to be stressed in such a way that triggers the body’s natural, adaptive response to new demands placed on it.- Progressive overload not only stimulates muscle hypertrophy, but it also stimulates the development of stronger and denser bones, ligaments, tendons and cartilage. Progressive overload also incrementally increases blood flow to exercised regions of the body and stimulates more responsive nerve connections between the brain and the muscles involved.- Conversely, decreased use of the muscle results in incremental loss of mass and strength, known as muscular atrophy (see atrophy and muscle atrophy). Sedentary people often lose a pound or more of muscle annually.- The loss of 10 pounds of muscle per decade is one consequence of a sedentary lifestyle. The adaptive processes of the human body will only respond if continually called upon to exert greater force to meet higher physiological demands. .