I don't agree with most people who are anti-Crossfit, especially not redditors, but I do agree with possible damage to yourself if you over exert and rush a workout; thing is, I was never allowed to even lift heavy weight during my time at Crossfit because my form was so bad. I lifted bars for months before I added weight. My coaches were extremely strict on me correcting my form before they'd let me add weight. Honestly, to the point that I was incredibly frustrated and felt like I was losing my strength because I stopped doing weight lifting when I started Crossfit.

Storytime; I was in my most fit ever when I joined Crossfit to help me with bulking up and cardio. I had already been doing boxing and muay thai for 4 years straight. I wasn't an amateur fighter or anything like that but I got in the rings and sparred and trained at least 5 days a week, usually 2-4 hours a day. I go to multi-discipline MMA gyms so they'll have muay thai/boxing/judo/bjj/yoga classes and I'd go from one to the other. Not uncommon at all if you can handle it.

After about 2 years of not being impressed with my strength and cardio (my Boxing coach wanted me to stay as lithe as possible) I did a trial class at a Crossfit gym. Burpees and wall-balls. Nothing crazy.

I got appendicitis the next day.