If you’re sitting right now you can easily test this. One thing you can do is if you’re sitting in a chair and your knees are at a 90 degree bend, you can just extend the knee of one of your legs to about 120 degrees and take a look at your quad. You can see that your quad obviously had to do something to actually extend the knee from that 90 degree bend, but it’s not entirely flexed or contracted, if you take that same foot and you raise the foot up into the air, and you totally straighten out the leg, and you flex the toes towards your body. So your feet are entirely out there entirely straight, they’ll see how the quad is entirely flex. So from going from that knowledge, you know that extra 30 degrees of knee bend from having it slightly bent, to fully straight you entirely engaging the quadricep muscles, which ensures that you’re actually using those muscles to their full capacity. So, the whole purpose of finishing the kick in front of the body is making sure that you’re using all the muscle groups to their optimum capacity and to their full capacity. With each kick, as opposed to just slightly engaging them the entire time.
With video analysis this is a really important key point, because it’s something you can see with underwater video very well in the Down-Kick portion, and a lot of kids especially if you’re coaching age groupers, young kids that are still building up leg strength. A lot of times you’ll see people have a great up kick, and not so solid Down-Kick. So they’re not actually getting really as much propulsion as they could, and they’re spending a lot of time in phases that kick that doesn’t generate as much speed. So overall, they’re kind of like self defeating themselves because they’re spending a lot of energy, doing stuff that doesn’t really get them to go forward.
As a population though, we are very very quad driven.So we’re pretty good at a lot of things that fire muscles in our front line to get out of the chair that you’re currently sitting in, you’re gonna have to use your quads, you’re gonna have to use some of your glutes, but not a ton of like the hamstrings or backline muscles. So, to make sure that you have a very even kick you want to make sure that you’re obviously strong in the front in the backs of your legs, but the Up-Kick portion or the hamstrings and glutes degrade over time as people get over older. A lot of times you’ll see people’s glute muscles and hamstrings end up not firing as well. So you want to make sure that there’s not a huge disparity between the front and the back line of someone’s strength analysis, because that can be directly shown in someone’s kick.
So making sure that you have a solid Up-Kick yourself through the back line of your muscles followed by forceful Down-Kick really use utilizing the quads as much as possible, is really going to even out that strength, if there’s a strength and balance and also give your yourself a pretty solid kick, overall.