Stretching
There are two main types of stretching categories:
Static
Static stretching involves stretching the muscles while the body is at rest. There are three sub categories
Active – muscles are stretched by the opposing muscle (antagonists are stretched by contraction of agonist). Normally held for 10secs.
Passive – external force is applied to stretch the muscle (partner helping to increase your range of movement (ROM). Normally held for 20-30 secs.
PNF (proprioceptive neuromuscular facilitation) – muscle is alternatively stretched passively (20-30secs) and contracted (10secs).
Dynamic
Dynamic stretching involves stretching muscles during motion. There are two sub categories.
Dynamic – a safe warm up which uses momentum to stretch mucles (e.g. swinging arms).
Ballistic – using momentum to forcibly increase the range of motion (bouncing while in stretch position). There is a high risk of injury when using ballistic stretching, so it is usually only used for sports specific warm ups.
Time to stretch?
The best time to stretch a muscle is while it is warm. Therefore stretching should not be left to the end of a weights workout, as only the last muscle worked will still be warm.