Multiple choice

Muscle fatigue is caused by the accumulation of

  1. pyruvic acid

  2. lactic acid

  3. oxalacetic acid

  4. uric acid
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Muscle fatigue during intense exercise is caused by the accumulation of lactic acid in muscle tissues. When oxygen supply is insufficient for aerobic respiration, muscles switch to anaerobic glycolysis, producing lactic acid as a byproduct. This buildup interferes with muscle contraction and causes the sensation of fatigue.

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