I'm honestly at a loss for words with this one. I don't understand how people in the batting cages next to him could keep their concentration, especially with his shouting. I know I'd burst out laughing, especially with his show of pride at the end. I suppose they have to try and concentrate on hitting the ball, lest they just get pegged by the machine as they sit there and marvel at this Karate Kid.
From what I caught (it's early in the morning, and I don't regularly watch Japanese TV, so give me a break), he does this as part of his training regimine for nunchucks -- presumably to improve his accuracy when hitting objects. It takes a lot of practice to be able to hit objects where you want to, so that's why I was also really impressed with his champagne bottle trick. Can any of you top him?
Dammit. I tried to find a picture of Michelangelo spinning his nunchaku on his finger from the first TMNT movie and put a caption that says "Keep Practicing!"