Fast and Slow Twitch Muscles

Skeletal muscle cells can be classified as slow-twitch (type I) or fast-twitch (type II) muscles on the basis of their type of respiration and speed of contraction.

Slow-twitch muscle

• Adapted for aerobic respirationAand so can continue contracting for long periods.
• Slow contraction speed, limited by rate of oxygen supply.
• No lactate produced, so not susceptible to muscle fatigue.
• Contain many mitochondria and the protein myoglobin, which…