Do you have bad or unstable knees?

Your solution: walking slowly on a treadmill BACKWARDS with an incline for 5 - 20 minutes.

Walking backwards improves knee stability because it activates the quadriceps more than forward walking, especially the vastus medialis oblique (VMO) — a key muscle that supports the kneecap. Studies show it also reduces anterior shear forces on the knee (less strain on the ACL) and enhances proprioception — your body’s ability to sense joint position. Together, these effects strengthen knee control and lower injury risk.