Hamstring injuries are very common in people who are involved in high impact sports where there is a need for increased acceleration or deceleration in any particular sport activity.
This injury is commonly seen in sprinters in athletics, soccer players, rugby players or any sport or indeed activity where there is a sudden increase of speed from a starting position of acceleration.
There are different grades of hamstring injury from grade 1 to grade 3 muscle tear. Most athletes or sports people will hear a sound when the hamstring tears and will often say they heard a snap or felt like someone hit them with a stone or a stick; some even describe it like they have been shot.
An athlete can expect to be out of competitive action from 10 days to six weeks when a muscle tears and if the athlete goes back too soon they are in danger of prolonging the sports injury even further, therefore it is of upmost importance of a correct rehab program and correct physical therapy/physiotherapy modalities, stretching, massage therapy, acupuncture etc. to help aid and speed up the healing process.
For me this is a general rule for all sports injuries especially soft tissue and muscle injury