What is a short-term muscular effect of exercise?

• A. Hypertrophy
• B. Strength and endurance increases
• C. Fatigue
• D. Increased tendon strength

Answer: (C)

Fatigue is the immediate, short-term change that happens in muscles during exercise. When you start exercising, your muscles use up energy quickly. Quick-energy stores like phosphocreatine run out, and if the work is intense, your body shifts to anaerobic metabolism, producing lactic acid. The buildup of metabolic by‑products and the depletion of energy sources slow things down, so the muscles can’t contract as forcefully or sustain effort as long. This drop in performance is temporary and improves after rest and refueling.

Longer-term changes take more time. Muscle size increases (hypertrophy) with repeated resistance work over weeks. Strength and endurance gains come from ongoing training, not a single session. Tendon strength also strengthens with consistent loading over a longer period.