I think it is likely that vertical movement of the pelvis , produced by forces generated through the stance leg , will help produce angular acceleration in the trailing swing leg during gait . For example in walking when moving from double support .

I also believe that the rapid , vertical , acceleration of the pelvis , through the explosive use of the standing leg, is and important contributory factor in the kicking action .

I should imagine all of the above is well documented and would appreciate a reference or two .

Cheers

Gerry