Properties of Muscles
1. Contractability - The unique quality of muscle which enables it to shorten at will.
2. Extensibility – Muscles are elastic and can stretch. They can increase their length by up to 50%.
3. Elasticity – After stretching, the muscle will return to its resting length and beyond.
Muscles can produce three types of contractions:
1. Concentric – a concentric contraction is one where the muscle contracts in order to overcome a resistance (usually gravity) and in doing so, the proximal and distal attachments move closes together. Sometimes referred to as dynamic shortening.
2. Eccentric – an eccentric contraction is one where the muscle dynamically lengthens under tension in order to overcome resistance and in doing so the proximal and distal attachments move further apart.
3. Static (Isometric) – a static contraction is one where the muscle is one where the muscle contracts but the proximal and distal ends remain the same distances apart, there is no joint movement but tension within the muscle increases.