Muscle Types

• Slow-Twitch Fibres have a large store of myoglobin, a rich blood supply and many mitochondria
• Slow-Twitch Fibres are located in the calf muscles, contracting slower, respiring aerobically for longer, adapted endurance
• Fast-Twitch Fibres are thicker, with more myosin filaments, a large store of glycogen, phosphocreatine and a high concentration of enzymes for anaerobic respiration
• Fast-Twitch Fibres are located in the biceps, contracting faster with short bursts during intense exercise