Which muscle group is primarily involved in knee extension?

The quadriceps muscle group is primarily responsible for knee extension. This group consists of four muscles: the rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius. Together, these muscles coordinate to extend the knee joint by pulling on the patellar tendon, which is attached to the tibia. When the quadriceps contract, they straighten the knee, making this muscle group essential for activities such as standing up, walking, running, and jumping.

In contrast, the hamstrings are primarily involved in knee flexion, the gastrocnemius assists with knee flexion as well as plantar flexion of the ankle, and the gluteal muscles primarily function to move the hip joint rather than directly affecting knee extension. Thus, the quadriceps muscle group's role in extending the knee is crucial in various everyday movements and athletic activities.