Hip Drive Swimming
In a non hip driven swim scenerio, swimmer primarily rotate the body by shoulders, while the hip rotation lag behind shoulders and the degree of rotation is less than the shoulder.
Examples of a swim without Hip Driven Technique: Jess Carlin, , Left shoulder rotation to the left most, while the hip is just in level positon.
The wrong kick timing on the right, cause a delay in the hip motion .
The body looks like a twisted plank.
In a Hip Driven swim, swimmers use kicking technique, not for purpose of greatest propulsion, but actively engage in hip rotation, in order to syncronise the shoulder rotation.
Syncronised hip and shoulder rotation will reduce the body cross section over the water, reduce drag and improve swim efficiency.
Example of Hip driven Swim:Katie Ledecky, with a hip driven swim, the pre-emptive Hip rotation with the proper right kick timing, rotate the hip at the same degree and same time as the shoulder.
The body is a perfect plank
Gary Hall Hip Driven Technique
Rotation Kick drill
US Masters Swimming