Which of the following reflects declines under reversibility principle?

• A. Aerobic and strength
• B. Flexibility and balance
• C. Speed and agility
• D. Cardio and power

Answer: (A)

Reversibility means gains from training fade when the stimulus is removed. The declines shown are most clearly seen in aerobic capacity and muscular strength because these adaptations rely directly on ongoing cardiovascular and muscular activity. When training stops, VO2 max drops as cardiac output, capillary density, and mitochondrial density diminish, and muscle strength decreases as the muscles lose size and neural efficiency. Other aspects like flexibility, balance, speed, agility, and power can also decline with detraining, but the most rapid and pronounced reversals occur in endurance (aerobic capacity) and strength.