I've been in and out of gyms for 30+ years, and one thing I have consistently noticed among most people is that they go to great lengths to avoid the floor. The lower the exercise, the less they want anything to do with it. This is especially common with men. There is a huge tier of "men" who don't even train their legs because women typically can't see them, then there is the "end ROM" tier (leg pressers, often,) and then there is the much smaller tier of men who do ATG squats, lunges, all the courageous lower limb work that is largely invisible....you know, basically the same stuff a lot of women do. Lol. That's right. Women are often tougher than men when it comes to leg and hip training. To be fair, they put that shit on display more than we do though. But showing off is not the only reason to train, unless you're dense.
But even among those who leg train, traditional trainees and athletes seem to think everything worthwhile must happen on the feet. The floor is dirty, stuff down there is hard, we're likely to encounter small muscles that don't work well, and maybe some mobility issues. Everything good happens near end ROM knee extension, right? Bullshit.
We are grapplers. There is nothing so beneficial to grapplers as being super strong in full knee and hip flexion, at the most mechanically disadvantaged ROM (in the hole, as they call it in squatting.) There is nothing so beneficial as having good single leg strength and power for scrambles and shots, for turning people over, bridging and escaping.
I am constantly thinking in terms of "how can I put more of a hurt on my butt, hips, and lower legs." Low, single leg training. The stuff that grapplers REALLY need includes: Low handle sled pushes. Bear crawls. Deep squatting or Anderson squats. Duck walks. Weighted duck walks. Lunges. Animal drills and sit out drills.
I have one goal in the weight room--to be able to take down a full sized man in my weight class from my knees. Not by standing up and running with him, literally with the reduced leverage hip power that comes from being strong on your knees. In most things, like sprints with sled drags, if you train handicapped, you will compete with a practical super power. And that is my goal.
It's not that I actually feel that I need to take someone down from my knees, I want to be able to chase them from a knee scramble the way Jordan Burroughs does, get my grips, and then stand them up with so much force that they can't even resist. You can obtain that from practicing regular shots, developing a nice deep squat, etc. But my aim is to train even lower. The box squat, the Anderson squat. Low handle sleds or even turf plate pushes.
Low, low, low. Leg attacks and leg strategy in wrestling seems to be all about who is more comfortable and more mobile in a lower squat--who can get under and stay under the opponent's lines of defense better (head, the lower arms, and the hips) and for longer. So being super comfortable super low should be the goal. A normal squat is, in a sense, for a grappler, an ego exercise. The excuse for squatting a lot bilaterally is that you can "use more weight" which increases overall load and thus adds more mass, but that is bullshit. The reason for it is feeling like a bad ass. They say "I want to take advantage of the stretch shortening cycle at the bottom of the squat" as an excuse for bouncing parallel or half squats, instead of employing ass to grass Anderson squats, box squats, or partials out of the hole.
People say the sticking point in the squat is parallel, which seems like it would mean that this is where the ROM is the weakest, but that is based around the false pretense of the stretch shortening cycle being important to the movement, and it is only important for competitive powerlifting, not for general athletic strength training (unless you are specifically doing speed/power/jump squats that depend on bar speed through full ROM.) If you are someone who box squats or Anderson squats from ATG, you know the REAL sticking point is the BOTTOM because everyone is naturally the weakest at full hip and knee flexion, not at some mid point where "the bounce" wears off.
People don't Anderson squat and then miss at parallel. It either moves or it doesn't. Note how in the bench press and the deadlift, people have different sticking points, depending on their experience level, and their biomechanics. New deadlifters are weak off the floor. Good squatters and advanced deadlifters actually often have problems at the deadlift lockout. The barbell back squat always has the same sticking point--the hole. Because after that bounce wears off, the mechanics suck. Get strong THERE to get strong everywhere. Which is why guys like Louis Simmons were always frothing at the mouth about box squats--they eliminate the cheaty bounce and build you an actual ass.
And then people act like cross training with Anderson squats is some form of magical plateau breaker for the "real squat." Well no shit, the traditional dive bombing back squat depends on a bounce through a deep low flexion range where you can't actually lift your 1RM. I would like to start an Anderson squat social movement that believes if you can't Anderson squat it, you can't actually squat it.
The second problem, which is being addressed by people like Mike Boyle, is that bilateralism is kinda shit for actual sports. When do you ever hop around like a bunny on two feet in sports? You are cutting on one leg or the other, using one more than the other, suffering from the vagaries of asymmetrical movement. You aren't perfectly balanced.
To this end, it would seem that the best athletic strength training in the world would then be single leg exercises that occur near complete knee and hip flexion. Pistol squats come to mind, of course, who does pistol Anderson squats, right? Hurry back up to standing, or people might figure out that you can't actually do it!
The Cossack squat is pretty bad ass. Try to find a video of someone doing it with a barbell, with any weight on it. Few and far between. Because everyone actually sucks at single leg, full ROM squat movements where you can't cheat with a bounce, or depend on balance gained from bilaterality and symmetry. Another exercise that has gained a lot of momentum over the past 10 years is the Bulgarian Split squat.
The only people in the world who are really consistently doing this kind of extremely asymmetrical low work--are dancers and ballerinas, and yoga and Pilates people. Ironically, people that are often viewed as "feminine" by people who think they are tough. People who can "squat" (usually half squat) 405 but who can't Cossack squat 135. People with robot hips.