Originally Posted by ayesr
I have found that (based on my own personal experience):
o that as I try to increase speed, my kicks become more vertical vis-a-vis cross-kick or diagonal,
o for some reason - with this vertical 2BK - the core body seems to be providing the major part of the overall forward speed
This is a great observation. It's also an example of how a shift in intention
can reinforce the same aspect of mechanics.
I made the same discovery via practice with the Tempo Trainer
When I raised my tempo above .9 sec/stroke (.86 to .89) I found that my 2BK became more "disciplined." There was no longer enuf time for the foot to slide sideways or to have extra "steadying beats." So the action became more vertical, and thus contributed more directly to weight shift, with a noticeable increase in the power naturally expressed by the weight shift.
When I felt that I recognized how important a more-vertical kick was, that became a separate intention
When I began practicing that intention without the Tempo Trainer, I found I needed to begin with short repeats and mini-kicks (ankles separating by only a few inches) because the neuromuscular circuits for a compact, vertical 2BK were not yet robust.
As I practiced this movement more -- and "grew more myelin" on that circuit, I was able to gradually increase repeat distance. Two years later I still can't maintain that kick for a full mile or more of racing, but I can maintain it for 200m to 400m repeats. I'm still working patiently on strengthening that circuit -- along with countless others.