Re: Too dangerous for children?
I have started my son (6) and my daughter (15 months) when the day they were born! Mainly holding them and helping them develop coordination and balance. My daughter will balance herself, fall, and roll around. My son, now that he is older is starting on rolling etc. Essentiallly tumbling. I am concentrating to be honest more on close in grappling and rolling at this point as I think it helps to work at this level from the ground. It is safer and the body connection and balance/feedback is much easier to communicate.
I have no evidence, but I am not a big fan of joint locks and throws at this age, at least for him.