Stair Negotiation Physics

Many people with pain in the front of their knee comment that going down stairs is more challenging and painful than going up. Let’s take a quick look at why that is!

In the images below, Dr. Scott compares the forces at work when going up vs. down a step. The yellow arrow indicates the force of gravity and the green arrow is the force placed through the kneecap. A larger arrow = greater force, and as you can see the higher degree of knee bend when going down creates a higher force, and thus more stress, on the knee. This can cause increased pain and make descending steps quite challenging for those with a painful knee condition.

Written by Dr. Scott Newberry

Dr. Scott going up the step
Dr. Scott going down the step