The semitendinosus is one of the three muscles that make up the hamstring group, located at the back of the thigh. It plays a crucial role in bending the knee and extending the hip. The muscle originates from the ischial tuberosity of the pelvis and inserts into the upper part of the tibia, contributing to movements such as walking, running, and jumping. This muscle works in conjunction with the other hamstring muscles, including the semitembranosus and the biceps femoris. Together, they help stabilize the knee joint and support various athletic activities. Proper strength and flexibility of the semitendinosus are important for preventing injuries in sports.