My back cracks while I'm hanging. Isn't that dangerous? It actually scared me.

This is what we warmly call the healthy crack - not damage, but a sign that the joints have finally been given space and are releasing. Many people actually say it's one of the most pleasant sensations while hanging. And here's the interesting part: with each session the cracking gets quieter and quieter, and then disappears altogether - you can tell by how the body loosens up. If something ever feels less like relief and more like discomfort, tell the trainer right away and they'll adjust your position.