There is no 100% guarantee not to get injured when you train Jiu-Jitsu, however if you take the necessary precautions you will lower your chances:
Do the warm up and stretch properly!
Everyone says that it’s super important for a reason. George St. Pierre keeps telling his friends and students that the body is like an ‘elastique’, it has to be warm in order to stretch, if it’s cold it will break. It’s a good analogy and this is something simple that people should keep in mind. Don’t roll until you have at least a light sweat going and you have gone over some functional movements to give your body a stretch. Shrimping, rolling, scooting and whatever other movements are essential to avoiding injury during the training. Also after class, it’s highly recommended that you stretch while your body is at it’s warmest to really help those tight and sore muscles. You will also improve your range of motion that will aid in your use of technique.
Choose your opponents wisely.
Did you just start training? Are you over 35 and some jacked 20 year-old blue belt spaz wants to roll with you? Maybe it’s better to take a rain check if you know the guy has a rep for hurting people or being too rough. The examples I used don’t cover all the kinds of opponent’s you should avoid. There are usually many factors involved, but if you know the guy cranks his subs, spazzes out and accidentally hits people, or if he is much larger than you, then it’s best to preserve yourself and pick someone else. It doesn’t mean you’re a wussy, it means you’re actually smart.
Don’t spaz out.
Just as it’s important to avoid guys that spaz, you also don’t want to be a spaz yourself. The less calculated you are, the higher your chances of tweaking a body part or collision. Headbutts, elbows and knees are some common collision problems in BJJ and the results can be quite gruesome. So play smart and use your technique – if you poorly compensate with strength or speed too often, you may face the consequences.