Muscle Fibre Types and Distribution

Slow twitch fibres have high mitochondrial density, high myoglobin content, high capillary density, low anaerobic capacity, and high aerobic capacity. They are designed for low-intensity, long-duration activities and are efficient for endurance activities.

Endurance training increases slow twitch fibre area, increases myosin heavy chain I expression, and increases mitochondrial density and capillary density.

The average distribution is 40-50% slow twitch fibres, 40-50% fast twitch fibres, and 10-20% intermediate fibres. The distribution is influenced by genetics, training and exercise, and muscle function and usage.

<p>Fast twitch fibres have low mitochondrial density, low myoglobin content, low capillary density, high anaerobic capacity, and low aerobic capacity. They are designed for high-intensity, short-duration activities and are capable of high power output.</p> Signup and view all the answers

<p>The subtypes are Type IIa (fast oxidative glycolytic), Type IIb (fast glycolytic), and Type IIx (fast intermediate). They differ in terms of anaerobic capacity, with Type IIa having high anaerobic capacity and moderate aerobic capacity, Type IIb having high anaerobic capacity and low aerobic capacity, and Type IIx having intermediate anaerobic and aerobic capacity.</p> Signup and view all the answers

<p>Intermediate fibres have intermediate mitochondrial density, intermediate myoglobin content, intermediate capillary density, intermediate anaerobic capacity, and intermediate aerobic capacity. They are designed for moderate-intensity, moderate-duration activities and are capable of combining high power output with moderate endurance.</p> Signup and view all the answers

<p>Resistance training increases fast twitch fibre area and myosin heavy chain IIb expression, while endurance training increases slow twitch fibre area and myosin heavy chain I expression.</p> Signup and view all the answers

<p>Genetics plays a role in determining muscle fibre distribution, with individuals having a genetic predisposition to a certain proportion of muscle fibre types.</p> Signup and view all the answers

<p>Muscle fibre distribution affects athletic performance, with slow twitch fibres being more suited to endurance activities and fast twitch fibres being more suited to high-intensity, short-duration activities.</p> Signup and view all the answers

<p>Muscle fibre distribution has implications for training and exercise, with individuals needing to tailor their training to their specific muscle fibre distribution to optimize performance.</p> Signup and view all the answers