I think youd need a complete programm to compete in the sabaki challenge .
some maybe able to do it without the weights , but I wouldnt like too . I feel I`d loose to much mass when overtraining and extreme fitness come into account . Also I beleive your body would need the contrast to stay healthy .
deffinatley the fitness and sparring .
Personally Id treat it as similar to a build up to a full contact Muay Thai fight . I`d want that level of conditioning so one could focus on the skill set .
Of course working on the sabaki style skillset instead , But I spend a lot of time in the Kick boxing gym getting knocked around .
I agree it`d be the ultimate in a karate sport format .
Sad if it`s true , but never the less , this is why Enshins a growing success , a real cutting edge competition that reflects there training emphasis .Unfortunately, I believe it is only open to Enshin blackbelts
this`ll no doubt remain a dream though . Incredible athletes ...