Hyperextension: Anatomy of the Knees: Function & Issues

What is It?

  • Hyperextension means that in extension, the knee joint has a greater range of motion than average.
  • “When the knee is straight, instead of the femur bone on top and the shinbones on bottom forming one straight line, your knee joint bows slightly backwards.” The kneecaps will likely turn in slightly, making the student look knock-kneed. (Nina Zolotow)


  • Hyperextension may lead to uneven wear on the cartilage of the knee joint.
  • It lessens the joint’s ability to respond and adapt.

Adaptability is Weakened

In a hyperextended knee, the natural position of the bones requires less muscular effort. But in this position, the tensegrity or supporting tension surrounding the joint is also gone. Without this support, the adaptability of the knee is weakened. The joint loses its critically important ability to respond to changes and demands from above and below. – David Keil

Teaching Considerations

  • Nina Zolotow offers a test here to distinguish hyperextension from knock knees: Stand in Mountain Pose and notice the knees turning inward. Bend knees and shift some weight to balls of feet. Straighten knees by lifting from thighs, keeping some weight in balls of feet. If knees are now facing straight, hyperextension has been corrected. “If there is no change, you may have knock knees. But try the adjustment once more just in case.”
  • Zolotow, as she learned from master teacher Donald Moyer, teaches the same technique as noted in the test for avoiding hyperextension in straight-legged standing poses. See more detail here.