This refers to tearing and the resultant bleeding in and around the hamstrings muscle at the back of the thigh. It is the result of a sudden tear of the muscle and bleeding into the muscle. It is most common in sprinting and running sports associated with a bad foot strike.
There will be considerable pain at the back of the thigh at the time of tearing and tearing sensation is often felt. As you cool down the bleeding and swelling will progress leading to further pain and stiffness. This may be sufficient to cause you to walk with a limp. It is advised that you stop participating and start RICE treatment to limit the swelling and shorten your recovery period.
If you think you have this injury it is well worth getting it checked out by Mr Willis-Owen. It is important to treat this early with rest, ice, compression and elevation in order to minimise the bleeding and swelling. You should avoid any aggravating activities which may prolong the problem. You may need crutches for the first few days. It generally will get better on its own if diagnosed early and treated appropriately.
Treatment involves first confirming the diagnosis and establishing the underlying cause. Physiotherapy and anti-inflammatories are required. Usually a carefully directed graduated physiotherapy program is all that is needed but recovery can be slow for severe injuries. Good early treatment and rehabilitation is required to prevent ongoing problems, and assessment of the underlying cause will help prevent recurrence.