Weight seemed to be an inaccurate term. Force plates measure force acting on the ground. Before you jump, you actually make yourself lighter because you aren't resisting the ground as you squat. Then when you do jump, you have to push with more force than your body weight otherwise you would not get off the ground.
Again,
weight is a force (mass x gravitational acceleration), thus, it is a very accurate and useful term provided gravity is constant - which is constant unless you intend to leave our planet. The same accurate term as mass in a given environment (gravity). Never say that weight is an inaccurate term then.
I said "again", since I said it all in a thread about weight shift not so long time ago. It is no rocket science we do not need any symposium to know such basic things. When you jump your weight is not constant because you add forces which orientation vectors are pro or contra gravity.
Shear force is our friend.
Oh, yes. A very good friend
We didn't really outright get into it, but if you just keep your weight on your left leg there is very little ground shear to push the hip turn with. Everything is stacked over the leg. All you can really do is push up as you said. You need that shear force to drive the right leg with and adds power to the very first part of the kinetic link.
Well said. The scenario of using rear leg horizontally oriented forces vs. lead leg vertically oriented forces is much more effective from the biokinetical point of view. Needless to say that the more horizontally oriented the force is the more room is for benefitting from shear forces and, consequently, torques.
Cheers