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

Hold something heavy in your arm close to your chest.

Now hold it far away from your chest.

You *know* the weight didn’t change, but it *feels* like it.

Not quite the same, but it’s a similar idea with your knees. Different parts have different mechanical advantages and experience different forces upon them.