According to the Principle of Use/Disuse, what happens if muscles are not used?

• A. Muscles will maintain their strength
• B. Muscular strength is enhanced
• C. Muscles will sustain definition and strength
• D. Muscles will lose definition and strength

Answer: (D)

The Principle of Use/Disuse indicates that muscles adapt to the demands placed upon them. When muscles are not regularly utilized, they do not receive the stimulus necessary for growth and maintenance. As a result, the body will begin to reduce muscle mass and strength, a process sometimes referred to as atrophy. This reduction is a natural physiological response, as the body conserves energy and resources and prioritizes systems that are actively being used. Consequently, without adequate use, muscles lose both their definition and overall strength, making option D the correct choice.