I have two gymnasts.. the older lvl 7 has had nothing to speak of. Just sore wrists when she started doing gymnastics. She never did gymnastics and started as a lvl 4 so learning back handsprings caused soreness for a little. It only lasted a few months and she was fine.
The other... well we've had a ton of fun with. She broke her foot doing gymnastics at home, a straddle jump off a bed. She got 15 stitches in her face after trying to vault over the coffee table. She broke her heal on beam and would sneak at the gym and take the boot off to do gymnastics.. child will be fully casted next time, lol. She sprained her ankle pretty badly a few weeks ago and is in PT 3 times a week for chronic sprains.. She has been doing gymnastics for just over a year, is a 6yo lvl for and has had enough gymnastics related injuries to last a life time for this mom.