Glycogen sparing involves what mechanism in endurance training?

Glycogen sparing involves what mechanism in endurance training?

• A. Increased mitochondrial capacity and enhanced fatty acid transport.
• B. Decreased mitochondrial density.
• C. Reduced capillarization.
• D. Increased glycogen use at all times.

Answer: (B)

Glycogen sparing in endurance training comes from increasing the muscle’s ability to burn fats, which reduces the reliance on glycogen during submaximal activity. The key mechanism is a rise in mitochondrial capacity and oxidative enzyme activity, paired with enhanced transport of fatty acids into mitochondria. With more mitochondria and improved fatty acid oxidation, a larger share of energy at a given endurance intensity comes from fats rather than glycogen, so glycogen stores are used more slowly. Capillary improvements also help by boosting oxygen and fatty acid delivery to working muscles, supporting sustained fat oxidation. Conversely, lower mitochondrial density would cut oxidative capacity and hinder fat use, while reduced capillarization or pushing glycogen use at all times would not support the sparing effect.

Glycogen sparing in endurance training comes from increasing the muscle’s ability to burn fats, which reduces the reliance on glycogen during submaximal activity. The key mechanism is a rise in mitochondrial capacity and oxidative enzyme activity, paired with enhanced transport of fatty acids into mitochondria. With more mitochondria and improved fatty acid oxidation, a larger share of energy at a given endurance intensity comes from fats rather than glycogen, so glycogen stores are used more slowly. Capillary improvements also help by boosting oxygen and fatty acid delivery to working muscles, supporting sustained fat oxidation. Conversely, lower mitochondrial density would cut oxidative capacity and hinder fat use, while reduced capillarization or pushing glycogen use at all times would not support the sparing effect.