The quad muscles, or quadriceps femoris, are a group of muscles located at the front of your thigh. They are the most voluminous muscle group in the human body and contain more mass than any other muscle group. The quadriceps femoris is composed of four individual muscles: the rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius. The rectus femoris is the only muscle of the quadriceps to cross both the hip and knee joints, and it flexes the thigh at the hip. The vastus lateralis, vastus medialis, and vastus intermedius are knee extensors.
The primary responsibility of the quad muscles is to help strengthen your knee, which allows you to perform tasks such as walking and running. They also help absorb impact when the heel hits the ground, maintain proper balance and posture, move and provide stability to the kneecap, and regulate the way that you walk. The proprioceptive afferents of the muscle contribute to maintaining adequate posture, and recent studies show that the activation of these afferents allows the contralateral quadriceps muscle to improve its coordination, increasing postural balance.
Your quad muscles are vulnerable to injuries, such as contusions (bruising) from blows to the front of your thigh, and quad strains or “pulled quads” can occur. To maintain quad muscles, it’s critical to provide them with sufficient stretching and exercise.
