Heel strike running was found to cause chronic knee pain by increasing frontal plane moments on the knee-joint. This is because the farther back you land on your heel when you run causes the knee to maximally extend (fully unbend) at touchdown. The big problem with this is it pushes initial foot strike position too far ahead of the body, which increases compressive forces on the knee while making the joint increasingly unstable because it’s locked out and stiff when fully unbent. Read more here!
