eli5: how does it work that for every pound of weight you lose, there is a 4 pound stress reduction in your knees?

Question

eli5: how does it work that for every pound of weight you lose, there is a 4 pound stress reduction in your knees?

In: 1542

Answer 1

This is one of the many reasons the metric system rocks and the imperial system blows. The gram is a unit of mass. Pounds is a unit of mass, force, and currency. So someone says “pounds” and you think mass, but they mean force, and everyone gets confused.

Long story short though, the forces going through your body are directly related to the weight of your body. Reduce the weight and you reduce the forces. How much are the forces reduced compared to how much the weight is reduced? There will be some function that varies with body mass, but its going to be complex.