Hi, just got hold of this thread.
the speed of your average oi-tsuki, be it jodan or chudan is pretty much the same. i.e. if you measured 1000 jodan punches vs 1000 chudan punches, the statistical differentiation would not be significant, Reason? the targets (on a static subject) are in the same range.
Having watched many good kumite videos, seeing our sensei fight shobu ippon at 'full speed/full power' and recalling my own natural instinct in kumite and more clearly other fight situations in the past, it always rings out that you should hit the face (causing more surprise and doing more damage) faster. Body shots are mainly used when up close, or even 'trading'.
My reasoning is that with a confident and committed jodan attack, our bodies will extend the straighter line from back foot, straight leg through hips (body dynamics) to straight arm, oi tsuki faster as it is a linear chain movement and as such, all the forces from the floor are transmitted in the same direction. Moley is especially good at demonstrating this. The final acceleration at the kime point should also be marginally faster than that of a chudan punch.
This though can be turned on its head in UKTKF competition kumite, where a well 'wound up' gyaku tsuki is the main scoring technique. However, I believe this is because of Lloydie's second point:
subjectively chudan punches may seem faster to some peeps, because they do not de-accelerate the punch as much as they do when targeting jodan - IMHO
We do tend to pull our 'ippons'.
W
