The hamstring muscle group is made up of three muscles, the biceps femoris, semitendinosus, and semimembranosus. They run from the ischial tuberosity (sit bones) down to the sides of the knees, just below the joint. The semitendinosus and semimembranosus attach on the medial side, and the biceps femoris attaches on the lateral side.
The hamstrings function is mostly to extend the hip and flex the knee. They help keep you upright against gravity by holding your body from flexing forward at the hip.
These muscles are crucial for most upright activities, including dancing, running, walking, jumping and as already mentioned, and bending forward.
Trigger points can flare in the hamstring group due to prolonged bed rest with flexed knees, or from sitting in a chair too long, especially if the front edge of the chair is pressing into them. They can also be overloaded with repetitive movements.
Trigger points pain is usually felt in the lower buttock and posteromedial thigh, and even down to the medial upper half of the calf. The biceps femoris will refer pain to the posterolateral side, and usually doesn’t extend as far into the calf.
Pain is often worse when sitting and walking, and can disrupt sleep.
Be cautious when choosing your chairs, especially lawn furniture that has a wooden or metal frame with a soft webbed or woven cushion on top, or bar stools without a footrest. Children are also at risk if sitting in a firm chair without the ability to rest their feet on the floor or footrest.
Try to change positions whenever possible during long car rides. Drivers can use cruise control if they have it so that they can change leg positions slightly at regular intervals.
Keep your hamstrings loose by stretching them out, rolling them with a foam roller, or kneading them with a tennis ball (just sit on it and roll around a little).
Warm baths are a great place to do a seated hamstring stretch!