To strengthen muscles, what action is recommended?

• A. Rest
• B. Cardio training
• C. Stretching only
• D. Lifting heavy weights

Answer: (A)

Muscle strength comes from challenging the muscles with resistance and then allowing time to recover. Rest alone doesn’t build strength because there’s no stimulus telling the muscles to grow or become stronger. Cardio training mainly boosts endurance of the heart and lungs, not maximal muscle force. Stretching improves flexibility but doesn’t increase muscle size or strength. The action that builds strength is lifting heavy weights (resistance training) with proper form and progressive overload, paired with adequate rest between sessions. Over time, increasing the weight or reps strengthens the muscle as it adapts to the increased demand.