Martial Arts.
About 8 years ago, I was in a wheel chair about 80% of the time due to a neuro-muscle disorder. I was in pain all the time, felt like I could do NOTHING because it hurt all the time. I just wanted to curl up and die. The pain really caused deep depression.
I was at my wits end when I discussed with my hubby (who is also a martial artist) that I wanted to give it a try. We talked about Tai Chi but the closest class was an hour's drive and I couldn't drive at that point (car was a stick shift). He felt that his style of martial arts would be too much for me. Well, doc's couldn't do anything to help me, just kept telling me to take this pill or that pill (none that worked) and the depression was about to claim me all together so I had nothing to loose...
We went and talked it over with his sensei (teacher). I started classes. I was told to work at my pace and not push myself too hard.
That first month was HORRIBLE! The classes were held in the basement of a building which meant stairs. My hubby had to carry me in and out each time. But at the end of the first month, I climbed those stairs BY MY SELF! I have not been in a wheel chair since. And except for the asthma meds, I'm med free.
At 2 1/2 months, I participated in a tournament and even took home second place in the "fighting" catagory.
I am now a brown belt, I help teach others, including the kids (they are such fun to teach). It totally changed my outlook on life and more importantly, my inlook on myself.
I would recommend a Shoin-ryu style of Karate but really, all are good. It is good exersize, good way to release energy, great way to release agression (kicking and punching the bags!) and more importantly, a great way to learn self control. And something your child can do with you usually starting about age 4 but some start earlier.
And age and size has nothing to do with ability in Karate. We have small children (6 yr olds) that can "throw" my hubby (who is not a small man) to the ground. We had a 90 year old woman, who is about 5'2" earn her black belt! She went on to teach self defence to the elderly at the community center.