Exercise associated muscle cramping (EAMC). The cause is unclear but maybe due to abnormal spinal reflex activity due to fatigue. This theory maybe supported by the effectiveness of passive stretching which reduces muscle and nerve activity within 10 to 20 seconds.
There is no compelling evidence proving that stretching prevents muscle injury during exercise or sport.
However, the ability to move a joint smoothly throughout full range maybe dependent on muscle length. Short muscles may stress other body parts. For example, short Hamstrings cancontribute to developing low back pain.
Trigger points are areas of intense muscle pain distributed over the body, sometimes referred to as Myofascial pain. However, they cannot be identified, as the pathophysiology is unknown. They are unlikely to be a primary pain source but rather “triggered” from another area. eg low back or neck pain. Trigger points maybe treated by massage, ultrasound etc but it is always worth identifying their causes.