When I think of JJ Watt I think of two things. One of the most dominant defensive players in NFL History, and a really high box jump.
About a year ago JJ Watt jumped to the top of an impressive 61 inch box. It looked something like the video below.
I mean who doesn't want to be as athletic as Watt? The guy is an animal. In response of seeing this video we all of a sudden had a flourish of people want to jump this high. Because if JJ Watt is athletic, and can jump to really high boxes, really high box jumps must make me athletic. As a result we get many videos much like this. (Look away if your squeamish)
First off, I'd like to point out that JJ Watt used actual boxes, and they were slightly cushioned. Never, ever, ever, should anyone use bumper plates to jump to high boxes.
Here's the thing; not only are high boxes dangerous in the sense of wiping out, but they also are not as effective of a tool of training athleticism as you might think. They can actually be an okay sign of a good athlete; I mean, you won't see someone make a high box that has no athletic ability, but they really have no place in a gym or in training.
One thing that happens in performing high box jumps is an athlete never really gets to true triple extension, nor true triple flexion for that matter.
Triple extension is one of the key foundations of power production and as a result, athleticism. It is the extension of the hip, knee, and ankle all at the same time. Look at an elite sprinter when they are pushing off, or better yet, check out this picture of 8th wonder of the world: Michael Jordan.
Or one of, if not the fastest man in history; Usain Bolt, look at his plant leg.
Bottom line, triple extension needs to be trained for power development. It's the foundation of power production and I could find picture after picture of top athletes in a plethora of sports at some point or another utilizing triple extension to create massive amounts of power.
If we were to watch again, we can scroll back up to JJ's box jump he has to bring his legs up so fast to actually land the jump that his hips never really get into full extension.
Second is triple flexion. If triple extension is the extension of your ankles, knees, and hips, then I think we can guess what triple flexion is.
The key with triple flexion is that it's the landing, it's the body absorbing the force of gravity. And this is crucial. When we get hurt it is usually when our body is absorbing force or transitioning from force absorption to force reproduction. For that reason it's imperative to absorb force properly.
One key thing to keep in mind is that in order to keep the back healthy we don't want the spine to be part of that force absorbing chain. In some instances it is inevitable, but of even more importance is that we shouldn't allow that to happen in our training. We can't always control what happens in the game of play, but we can control our training. And the better our body becomes at absorbing force the right way during training, the more prepared it will be in doing so during a game, when, let's be honest, we could careless about using proper mechanics.
The other danger that happens comes when we repeatedly subject our low back to such force, over time it will lead to issues. It is not always acute, but make no mistake, the damages we put on our body now will be paid for eventually.
Let's look at the kind of force absorption that our body goes through during the performance of really high box jumps.
Look at that guys low back. The thing is, even a respectively high box jump can do that.
I hope I'm making some sense here. Most of us, if we're being honest really don't need to jump higher than a "24 inch box. Very few of us may go up to "30. Make no mistake, if we start losing triple extension and triple flexion we are losing an aspect of power training that should not be ignored.
All this to say, I love box jumps, I love them as a teaching tool for power training when used properly.
If you have any question about whether your box is too high take a look at your landing. As I've learned from Mike Boyle, "you're landing should look like your jump". If you're hips are lower on your landing than on your loading phase of the jump than you're box is too high, and perhaps your ego is as well. Check your ego at the door, and lower the box. Your back will thank me, and depending on what kind of boxes you have you're shins will thank me too.