Physical Danger
Most choreographers start out as dancers who all get to know their physical therapists very well. You can't expect to spend all day jumping and flipping around and never get hurt. Dancing can also take a major toll on your body over time; eventually, stuff just starts to break down. Just like with professional athletes, some dancers eventually have to stop because their body says, "Okay, I seriously need some time off."
The good news for choreographers is that the physical danger isn't quite so dire. In fact, some dancers begin their careers as choreographers once their bodies start to catch up with them. Most choreographers do demonstrate the steps to their dancers, but they rarely do them over and over again with the troupe.
As a choreographer, you've got to take a step back and analyze the whole; so compared to your full-time dancing days, you now have more of a risk of spraining your brain than your ankle.