What is the term for lactic acid buildup due to repeated muscle contraction without proper nutrients and oxygen, causing a burning sensation?

• A. Delayed Onset Muscle Soreness
• B. Muscle Cramps
• C. Dehydration
• D. Muscle Fatigue

Answer: (D)

The main concept being tested is how muscles respond when they’re asked to contract repeatedly without enough oxygen and nutrients, leading to lactic acid buildup and a burning sensation. When work is intense, the body shifts to anaerobic metabolism to keep energy flowing. This process produces lactic acid (and hydrogen ions), which accumulate in the muscle, lower its pH, and irritate nerve endings, producing that burning feeling. As energy stores are depleted and waste products build up, the muscle’s ability to contract declines, which we describe as fatigue. The other options describe different phenomena: delayed onset muscle soreness appears hours to days later after unfamiliar or intense activity; dehydration relates to fluid loss and can contribute to fatigue but doesn’t specifically explain lactic acid buildup; muscle cramps are sudden, involuntary contractions. So the term that captures the described situation is muscle fatigue.