No matter how much you try to evade them, injuries are bound to happen in Brazilian Jiu-Jitsu. That’s just the way it is; as it’s a martial art, you’ll see some tweaks (and unfortunate breaks) here and there. However, everything possible should still be done in order to minimize the chances for serious mishaps.
For instance, there are two very simple safety rules that all BJJ instructors should implement in their Jiu-Jitsu gyms. John Danaher shares what these safety rules are.

TWO SIMPLE SAFETY RULES FOR BJJ TRAINING

The first safety rule that Professor Danaher talks about is not letting the students sit, in the middle of a sparring session, in the middle of the mat with their arms hyperxtended (resting) behind them.
If this rule isn’t utilized in the training room, it’s only a matter of time before one or two athletes, rolling in the background, smash into a student that has his arms hyperextended as explained. And when one (or two) people smash into a hyperextended elbow with their full weight… Well, you can be more than certain that that will be an extraordinarily successful Armbar.

Secondly – and in coherence with the advice given above – Professor Danaher advises BJJ instructors to develop a gym culture where students sit with their back against the wall. This is to be applied if they’re resting during the sparring session.
With students sitting with their back against the wall, there’s a minimal chance that they’ll get injured by another training partner.

Watch the video below to get more of an understanding why these two simple safety rules need to be applied: