Resistance training tends to produce which primary adaptation in body composition?

• A. Decreased lean mass
• B. Increased lean mass (hypertrophy)
• C. Increased fat mass
• D. No change in lean mass

Answer: (B)

Resistance training mainly increases lean body mass by driving skeletal muscle hypertrophy. Repeatedly exposing muscles to overload creates mechanical tension and micro-damage that activate muscle-building signaling pathways (such as those leading to increased muscle protein synthesis). Over time, existing muscle fibers grow larger, increasing the amount of lean tissue in the body. While fat mass can decrease or stay the same depending on overall energy balance and nutrition, the most consistent and primary body composition change with resistance training is an increase in lean mass through hypertrophy.