Found this article talking about the BJJ self defense video that was posted earlier: The BJJ Self Defense Experiment I especially liked this part: The Heel Hook for Self Defense The Heel Hook, this one single submission, accounted for just under half of ALL submissions applied during the experiment… Why did this one submission show up again and again and again? In part it was because all three experts are really, really skilled at the Heel Hook (Garry Tonon, in particular, is feared for his relentless lower body attacks in competition). But these guys are good at all aspects of jiu-jitsu, so that fact doesn’t completely explain why this one particular leglock was so powerful… It seems like once the gi comes off that submissions tend to gravitate towards the legs and the neck. Take a look at modern no-gi competition, old-school catch wrestling, and Brazilian Luta Livre back in the day: they all are no gi grappling arts and all had great chokes and great leglocks! Another aspect of the Heel Hook that makes it so powerful for self defense is that it doesn’t require much strength. In this submission you’re attacking the relatively small ligaments in his knee and ankle, and he can’t really use strength to muscle out of the submission. If you have to apply this submission in anger you use the relatively big muscles of your torso against the much smaller ligaments, which is usually accompanied by a loud popping sound and your unfortunate opponent dry heaving on the floor. (That makes the Heel Hook one of the biggest equalisers you can use if you’re fighting someone much bigger than you.) Also it keeps you safer from strikes. An opponent who knows that you’re hunting for a Heel Hook is usually going to be pre-occupied with defending this submission. Unless he’s an idiot he knows that he’s close to tapping out; he’ll be trying to escape and won’t be concentrating on breaking your nose. In addition to him being distracted your legs are also in a great position to disrupt his base. If he’s on his butt and you’re entangling his legs correctly then it’s hard for him to stand up. I definitely agree that if you're fighting someone a lot bigger and stronger than you, and you're in a position to use it, those types of locks can be a very viable option.