Take walking. We walk by pushing down and backwards ... From the moment your matching action/reaction forces accelerated you and whatever you stepped on, you'd both keep heading away from one ...

In those with patellofemoral pain, peak PFJRF were: walking 0.8±0.2 BW ... the PFJRF broadly and simply as the magnitude of the net reaction force between the patella and femur due to the action of ...

It's simple. What's Wrong With the Other Version? There isn't anything exactly wrong with the "action and reaction" version of this part of force? First, no disrespect to Frank's Action-Reaction ...