S2, L1: Force, strength and power

What are the 3 mechanisms of muscle strength gain?

• Fibre hypertrophy

• Fibre hyperplasia

• Motor unit recruitment

Describe the methods of fibre hypertrophy (4)

• Resistance training influences protein metabolism - after exercise protein synthesis increases and degradation decreases

• Testosterone facilitates fibre hypertrophy and is a natural anabolic steroid

• Genetics can influence the rate of hypertrophy

• Synthetic anabolic steroids cause large hypertrophy

What is fibre hyperplasia?

Fibre splitting, where each half then grows to the size of the parent fibre

What is the issue with fibre hyperplasia in humans?

There is very little and low quality evidence for fibre hyperplasia in humans due to the practicality of counting fibres in a whole muscle, which is easier to do with a cadever

How does motor unit recruitment influence strength gain?

• Normally motor units are recruited asynchronously

• Resistance training leads to a more synchronous recruitment of motor units, leading to increased strength and an improved rate of force development