Which muscle is listed as active during knee extension and is not part of the quadriceps group?

Which muscle is listed as active during knee extension and is not part of the quadriceps group?

• A. Rectus Femoris
• B. Vastus Medialis
• C. Tensor Fasciae Latae (in 0-30 degrees flex)
• D. Popliteus

Answer: (C)

Knee extension is dominated by the quadriceps, but other muscles can influence the knee through their fascia and stabilizing roles. The tensor fasciae latae is not part of the quadriceps, yet it can be active during extension by tightening the iliotibial band. When the knee is in the shallow flexion to near-extension range (about 0–30 degrees of flexion), contraction of the TFL increases tension in the IT band, helping to stabilize the lateral knee and support alignment as the knee extends. That indirect involvement makes it appear active during knee extension, even though it isn’t a knee extensor itself. In contrast, the popliteus mainly contributes to unlocking the knee from full extension and is active during the transition into flexion, not during extension.

Knee extension is dominated by the quadriceps, but other muscles can influence the knee through their fascia and stabilizing roles. The tensor fasciae latae is not part of the quadriceps, yet it can be active during extension by tightening the iliotibial band. When the knee is in the shallow flexion to near-extension range (about 0–30 degrees of flexion), contraction of the TFL increases tension in the IT band, helping to stabilize the lateral knee and support alignment as the knee extends. That indirect involvement makes it appear active during knee extension, even though it isn’t a knee extensor itself. In contrast, the popliteus mainly contributes to unlocking the knee from full extension and is active during the transition into flexion, not during extension.