No I'd say it's not, a lot less dangerous than professional motorcycle racing or downhill skiing. But like anything, you're pushing your body to the limit so you will get injured. Mark Felix has just retired at 57 and if you watch him he's limping and can't straighten his arms. I expect his joints will be fucked in a few years.
A friend of mine does string woman and she's fit as a fiddle and follows a strict exercise and nutrition routine. I'm sure it's a lot better for you to be a strongman/woman than sitting on a sofa eating leftover Christmas goodies and drinking alcohol