This type of takedown is very good. In Brazilian Jiu Jitsu, it's often referred to as an "X guard sweep". Using this type of takedown shown in the video involves throwing yourself to the ground- not a great idea in most circumstances. But the principle body mechanics you can see in this footage is good. You can use modified versions of this technique, from your back, to tangle up opponent's legs and keep your hips above theirs. **If your hips are above your opponent's, you are at the advantage.** You can even see this in the scissor takedowns- they have to raise their hips up, entangle legs, and then let physics do the rest of the work. It does not take strength to use techniques like this (it helps, though)- it takes *skill* and *timing.* All about using body mechanics against itself.