Red muscles (Example: extensor muscle on back of human body) 1. Red muscles are thin muscle fibres 2. Red in colour due to the presence of large amount of myoglobin 3. Slow and sustained contraction 4. Depend on aerobic metabolism for energy (oxidative phosphorylation) 5. Mitochondria is abundant 6. No accumulation of lactic acid 7.
* Most skeletal muscles contain a mixture of all three types of skeletal muscle fibres. However, the proportions of the different types of fibres that form specific muscles vary according to how the muscle is used - and, to a certain extent, also on genetic factors.