GLOSSARY

The quadriceps femoris is the largest muscle group on the front of the thigh, made up of four muscles, and is the main extensor of the knee.

Members

• Rectus femoris: the only two-joint muscle of the group, arising from the pelvis.
• Vastus lateralis: the largest, on the lateral side.
• Vastus medialis: on the medial side, forming the “teardrop” above the knee.
• Vastus intermedius: deep, beneath the rectus femoris.

Attachments and Innervation

• Common insertion: the quadriceps tendon to the patella, and via the patellar tendon (ligament) to the tibial tuberosity.
• Nerve: the femoral nerve (L2–L4).

Actions

• Knee extension.
• Hip flexion: rectus femoris only.
• Eccentric control: shock absorption on landing, descending stairs, and running downhill.

Relevance to Sport

• Sports: running, jumping, cycling, skiing, football, and weightlifting.
• Exercises: squats, lunges, leg press, leg extension, and Bulgarian split squats.
• Knee injury: after an ACL injury or knee surgery, quadriceps weakness and atrophy are very common, and restoring at least 90 percent of the uninjured side’s strength is a key return-to-sport criterion.
• Patellofemoral pain: quadriceps strengthening, together with hip muscles, is the most effective treatment.