The question may have seemed pointless to you but my point in asking the question was to generate discussion. There may not be a single best movement to develop the aspects I mentioned but the list is limited. As you said the “best” movement for one athlete may not necessarily be the “best” for another. I assume that this forum would be the place to get the best advice on coaching the sprint. To me it would be pointless to ask individuals (even ones on this forum) who had never seen a particular athlete what the best exercise for THAT athlete would be. I am not without ideas but am always looking to improve the ones I have.