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 shifting fuel use toward fats by boosting the muscle’s oxidative capacity. Regular endurance work expands mitochondrial density and raises the enzymes involved in fat metabolism, plus improves the transport of fatty acids into mitochondria. With a greater ability to oxidize fats, the muscle relies less on glycogen for energy at submaximal intensities, preserving glycogen stores for longer duration or higher effort.

If the system had fewer mitochondria, fat oxidation would be limited and glycogen would be used more quickly. Reduced capillarization would slow delivery of oxygen and fatty acids to the working muscles, hindering fat metabolism. Using glycogen more rapidly at all times would defeat the purpose of endurance adaptations aimed at conserving glycogen.