Also, the distance from center of the rotation matters.
For instance, doing a bicep curl with a 10 pound weight with your elbow by your side is easy.
Holding that 10 pound weight with your arm straight and lifting it up to eye height is much more difficult, but for most people without impediments still doable.
Now imagine the difference in distance between the ball and heel of your foot versus the distance between your knee and your hip.
Also, the distance from center of the rotation matters.
For instance, doing a bicep curl with a 10 pound weight with your elbow by your side is easy.
Holding that 10 pound weight with your arm straight and lifting it up to eye height is much more difficult, but for most people without impediments still doable.
Now imagine the difference in distance between the ball and heel of your foot versus the distance between your knee and your hip.