Final answer:
Anaerobic respiration in muscles produces lactic acid as a byproduct, which is notably less efficient at generating ATP compared to aerobic respiration and can lead to muscle fatigue.
Step-by-step explanation:
The product of anaerobic respiration in muscle tissues is lactic acid. During strenuous exercise, when oxygen supply to muscle tissues is insufficient, pyruvic acid derived from glycolysis is converted into lactic acid. This process allows the continued production of ATP through glycolysis by recycling the enzyme NAD+ from NADH. Although this method allows for short bursts of high-intensity exercise, the accumulation of lactic acid may contribute to muscle fatigue. Anaerobic respiration, in contrast with aerobic respiration that occurs in mitochondria and produces approximately 36 ATP molecules per glucose molecule, yields only about two ATPs per glucose molecule due to its less efficient usage of glucose.