While I'm not sure I am a "pure" ADHD/ADD case, I am certainly a survivor of OCD, which is arguably a subset. I still exhibit some of the symptoms today (compulsivity, impulsive actions, unrestrained creativity, hyper-focusing on specific activities.) Interestingly, there has been some research done looking into the effects music practice, martial arts, and yes, weightlifting, have had on ADHD/ADD patients. Apparently the discipline and routinized, methodical, mental application required by these disciplines activates a part of the brain that suppresses the symptoms of ADD/ADHD.
I've never taken any medication. My childhood was extremely difficult due to my condition, but I attribute my success of "growing out" and learning to suppress/ignore the OCD/ADD/ADHD symptoms to those activities.
In sum, I personally believe, as someone who never had the aid of medicinal solutions, the key to controlling said negative behaviors is to 1. have goals 2. be busy pursuing those goals 3. minimize stress. For someone like myself, I can quickly enter a positive feedback loop of mounting stress once I "lose sight" of my accomplishments and future challenges. When boredom sets in, I find that the negative behaviors can quickly crop up again. I think, in many ways, childhood is very difficult for ADHD/OCD/ADD cases because childhood, in general, is pretty boring. You aren't self-sufficient enough, or cognizant enough, to establish goals and have the means by which to seriously accomplish them.
If you have any more questions about my personal journey, I'd love to share some more insights.
PS.: I have found the study of Zen and zazen (meditation) to be extremely helpful. Activites like martial arts, weightlifting, and the practice of musical instruments require much of the same "active relaxation" of the mind as pure meditation.