The research says that a "Faster rotation of shoulders in the transverse plane" is associated with a better running economy in well trained runner. But, I have no idea of what that means. I've even watched that video on YouTube analyzing Kipchoge's (if someone have a good RE it's definitely him) running form, but I couldn't discern any "Faster rotation of shoulders in the transverse plane"
Do you guys have any idea on this?
Link to the study: