Many instructors in BJJ begin teaching students in these terms
Passing, Sweeping, Maintaining Positions, Attacking Upperbody Submissions and escaping them. Most styles save leglocks for higher belts or never train them at all. There are a few different reasons for this:
"Leglocks are not effective"
"If your students learns leglocks early, they wont learn to pass the guard"
"Leglocks are too dangerous for new students to learn and apply safely"
I've heard all of these reasons before and while I think there might be a little logic to the latter reasons the first is certainly ridiculous. Having seen leglocks used with great success very often lately I think I can safely say they work very well. As for the second reason, I'll say this, if your student really just sits back and taps everyone with heelhooks why learn guard passing at all? Obviously you can't leglock everyone and so your students will experience that and learn to pass the guard. As for the third reason students who are too spazy and uncontrolled to learn leglocks they probably can't apply armbars and chokes with control either.
I believe leglocks might be the best option as first attacks once a takedown or guard pull has occured. The main reason being is that they can be entered into from either the top or bottom as long as you gain inside control on your opponent. Going for leglocks from the bottom often leads to very effective off-balancing and sweeping techniques which might be otherwise overlooked or considerably less effective without the threat of leg entanglements. Conversely Attacking leglocks on top against an opponents open guard seems to open up unique passing opportunities which is helpful since passing an open guard without the use of leg attacks is one of the most difficult things in bjj competition. So many matches in which leglocks are not permitted end either no pass or sweep and are decided instead by advantages. Or if there is a pass or sweep it seems to be only enough time to just do that one sweep or pass and not reach a submission. Leglocks create a more dynamic level playing field where the guard player cannot simply retain his guard with no fear of submissions.
This is just my opinion and I am open to anyone who disagrees or has ideas they'd like to comment about
Oss!