Quote Originally Posted by RenDaHai View Post
During training however the most annoying I find is injuring the thumb. Where it is tucked under the fist it can get caught and pushed backwards. Especially when your partner is partial to using the elbows to block. When you push through and really try to hit him it catches on the guard.

So much so I have taken to often holding the thumb to the side, or even partially inside the fist (joint still outside but nail tucked in). Sounds weird I know but it has its advantages.
This has happened to me so often in sparring, I've also had to use the "Isshinryu style" to compensate. Unfortunately, I've even injured it in that position as well; on occasion.

What's interesting to me is, almost everyone punches with thumb on the side of the fist, but if you wear boxing gloves, they force you to keep the thumb more on the top of the fist...