Knee extension is best described as:

• A. Rotating the knee inward
• B. Bending the knee
• C. Straightening the knee
• D. Extending the hip

Answer: (C)

Knee extension means straightening the knee. When the leg moves from a bent position to a straight line, the angle at the knee joint increases toward full extension. This action is produced mainly by the quadriceps muscles contracting and pulling the tibia forward through the patellar tendon, with the hamstrings helping control the motion. It’s not about rotating the knee inward, which would be a rotational movement; it’s not bending the knee, which would be knee flexion; and it’s not extending the hip, which is a movement at a different joint.