Type I fibres have high levels of which components?

Type I fibres have high levels of which components?

• A. Myoglobin
• B. Glycogen
• C. Myoglobin and mitochondria
• D. Lipids

Answer: (C)

Type I fibres are built for endurance and rely on aerobic energy production, so they are rich in the components that support sustained oxygen use. Myoglobin stores oxygen inside the muscle, supplying it to the mitochondria, while a high number of mitochondria allows continuous oxidative phosphorylation to produce ATP. This combination makes the fibre dark and efficient for long, steady activity. Glycogen content is typically more associated with fast, powerful contractions that rely on anaerobic glycolysis, and lipids are used as fuel but aren’t the defining high components in these fibres.

Type I fibres are built for endurance and rely on aerobic energy production, so they are rich in the components that support sustained oxygen use. Myoglobin stores oxygen inside the muscle, supplying it to the mitochondria, while a high number of mitochondria allows continuous oxidative phosphorylation to produce ATP. This combination makes the fibre dark and efficient for long, steady activity.

Glycogen content is typically more associated with fast, powerful contractions that rely on anaerobic glycolysis, and lipids are used as fuel but aren’t the defining high components in these fibres.