Question

Assertion :Fatigue is inability of muscle to relax. Reason: It is due to lactic acid accumulation by repeated contractions.

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion.
• C. Assertion is correct but Reason is incorrect.
• D. Both Assertion and Reason are incorrect.

Answer 1

The correct option is A Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.

An individual’s capacity to perform during high-intensity exercise depends on upon his/her ability to generate and maintain a high power output. That ability requires both a high anaerobic capacity and the functional ability to generate the necessary force and velocity for a given power requirement. The inability to maintain the desired power output defines fatigue and mechanisms that attempt to explain fatigue have been generally classified as product accumulation or substrate depletion.

Anaerobic glycolysis produces lactic acid and, at a physiological pH, most of the lactic acid dissociates into H⁺and lactate. While the majority of H⁺produced in muscle is from glycolytic products, there are also other contributors to intracellular H⁺accumulation including a reduction of intracellular [K⁺], synthesis of CP, and the buffering of CO₂ produced in the mitochondria. The decrease in muscular pH affects several sites in muscle, which lead to fatigue.

Therefore, the correct answer is option A.