This is a layman's term for a strain or torn hamstring. The hamstring muscles are the collection of muscles on the back of your thigh. They are often injured during strenuous physical activity.
One would know that it is injured primarily from he pain in that region with running or even walking if severe. since it is such a large group of muscles, complete rupture of the entire muscle is unheard of.
If you think you have, the only real treatment is ice to the area if recently done, rest the leg, and elevate it as much as possible. Over a few days, you may notice bruising tracking down your leg, or maybe not.
Limit your walking activity and use tylenol for the pain initially. Later on, you can switch to aspirin, aleve or ibuprofen. You don't want to use these three drugs early on as it could increase the bleeding from a partial muscle tear. These injuries may take many weeks to heal and you may limp for several weeks after the initial injury.
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