The Ring-Con that comes with this game is very sturdy. As someone who can bench quite a bit, I must say that I'm impressed with the quality and resistance of the ring. I can actually get a good workout in with this game alone.
When I bought it, I thought it was pure cardio - but it's certainly not! Cardio is a big part of it, and you'll get sweaty.
Excellent game for getting that fitness motivation back at home. For anyone not into doing serious weights, this game will completely replace all other fitness needs. Personally, I'd still use my dumbbells for some benching, and some triceps training, but this game is really great all-around for most people.