So what do we know about the hamstrings, other than me making you stretch them in class and getting the odd painful cramp?
Well let me educate you – the main function of the hamstrings is to bend your knees. This is a movement you use in all daily activities such as walking, running, climbing stairs and jumping. The hamstrings also help rotate your lower leg. Two hamstrings attached to the inside of your knee rotate your lower legs inward. The third hamstring, attached to the outer border of your knee, rotates your lower legs outward. These movements fine-tune the position of your lower legs as you walk. Your hamstrings also act like brakes to slow the speed at which you swing your leg forward while kicking or running.
There are three muscles which make up the hamstrings, these being:
Biceps Femoris
The biceps femoris is what is known as a two headed muscle. It consists of two parts: A longer part which attaches to the seat bone and the short head which attaches to the femur (thigh) bone. The biceps femoris muscle is important for knee flexion (bending the knee), internal and external rotation (rotating the leg side to side) and hip extension (taking the leg behind the body). A pain in biceps femoris can be caused by several reasons. The most common thing is a strained muscle caused by improper lifting or too much exercise.
Semimembranosus Muscle
It is found on the back of the thigh and runs from the base of the pelvis (seat bones) to the back of the tibia, one of the bones that make up the lower leg. The semimembranosus muscle is attached to the pelvis and tibia with tendons. The semimembranosus muscle has several functions, including enabling the leg to flex and rotate and serving as a thigh extensor.
Semitendinosus muscle
The semitendinosus muscle lies between the other two hamstring muscles. These three muscles work together to bend the knee and extend the hip. The semitendinosus muscle begins at the seat bones. It inserts next to the Semimembranosus muscle.
