Injuries are an unfortunate a part of grappling sports. The odds of remaining completely injury free are not in your favor if you train for long periods of time. That said most injuries are minor and result in minimal loss of mat time.
Injuries that result from joint locks are among the most preventable. Both the attacker and the defender share responsibility for preventing these injuries. From the offensive side, it is a requirement that all locks be applied at a slow speed once the hold is secured so that the defender has time to tap out. More advanced students should avoid applying locks that newer students have never seen before because they may not realize that they have been caught.
The defender must realize when he is caught and tap out. Unless he submits verbally or by tapping the attacker will not know when to release the pressure. All too often people wait until something causes actual damage before tapping or they don’t tap at all and are seriously injured. Not tapping when getting choked isn’t as big a deal. You pass out, wake up, and everyone is ok. Trying to tough out a joint lock can lead to weeks or months of injury time and/or surgery.
A final note is that sometimes even when a person taps, there can still be an injury. Consider this situation. The attacker is cranking furiously on your leg attempting to finish a straight Achilles lock. You are defending but realize that you have no strength left. You decide to submit. You stop your defense and tap. Suddenly the pressure comes on in full and you have a sprained foot.
The key to preventing this situation is to tap out while you are still actively defending. There will be a delay from the time you decide to submit and you make that decision known to your partner via tapping or saying stop, and when he hears it and lets off the pressure. If you have stopped fighting before you submit, he will likely injure you in that second it takes for him to recognize your tap.
Brian Jones, PhD