Regular weightlifting is necessary for good health. Weightlifting with heavy resistance, especially with compound movements, helps break down and rebuild stronger muscle fibers, resulting in strength and size gains. Which one of the following is an assumption required by the argument? ['Compound movements are the only way to increase strength and size.', 'Regular weightlifting is necessary for good health.', 'Performing compound movements is the only way to break down and rebuild stronger muscle fibers.', 'Strength and size gains are indicators of good health.']