Friday, August 26, 2011

Exercise of the Week: Box Jump

The most important movement in which a karateka needs strength and power is the hip snap - the last few degrees of hip extension.  Think of what happens when you punch - the hip is driven forward by extension, and it's not from a deep squat or anything, it's right from a slightly flexed hip, the way you hold it in a casual stance, to full extension.  The same thing drives a front kick - the supporting leg snaps the hip forward, again extending the hip through a relatively short arc of motion.  Ditto for a side kick, except then it's the kicking leg that gets force from the hip snap.

My favorite way to develop this hip snap power is the kettlebell swing, about which I intend to write more at some point.  Lately I've been using box jumps to develop hip power as well.


  1. Stand upright in front of a box or platform.  It has to be sturdy - not something that's going to easily fall over.
  2. Quickly dip down, not into a full squat, but more into a quarter squat.  Think of a basketball player going for a rebound - they don't squat all the way down, just a quick flex of the hips.
  3. Jump up quickly.  Don't pause at the bottom - dip down, then jump up as rapidly as you can.
  4. Land on the box in a crouch position - knees up in your chest. 
The box should be high enough that you barely reach the top - you're not trying to jump up very high, then come down a long way and land on the box.  You're trying to just barely reach the box, and you should have to land in a deep squat position.  If you can land in an upright stance the box is too low.


Don't do a ton of reps.  Try 3-5 jumps each at 3 different heights.  The first 2 heights are warmups.

Use these at the beginning of the program, after your warmup, mobility training, and dynamic stretching.  DO NOT do these when you're tired, it's both counterproductive and dangerous.

Do these maybe twice a week at most.  Once a week might be better.


I like this exercise for a few reasons.
  • This really encourages you to generate maximum power.  Jumping higher is very compelling.
  • This movement is functional in the sense that you're training for and learning to jump onto high objects.  You might very well have to do that - in an emergency, when running from or after somebody, etc.  Jumping onto things is part of real life in the way that bench pressing just isn't (I mean, it's possible that a perfectly balanced cylindrical object could fall across your chest as you lie on your back, but I think it's more likely that you'll have to jump onto or over something at some point in your life).
  • The hip snap is followed by a very rapid hip flexion (the movement of quickly bringing your knees up to your chest so your feet clear the box).  I find that very little in my routine trains hip flexion, especially at speed, and nothing will improve your front kicks more than some improved hip flexion strength.  Box jumps give you twice the bang for your buck - and this is one way they improve on the kettlebell swing.
  • You can find plenty of videos online of people doing box jumps onto specially designed plyo boxes, but you can also use low walls and ledges or anyplace outside where there are elevation changes.  Kettlebells are expensive; walls are often freely available for our use. 
  • If you just jump high, or jump over something, then you have to land.  Landing can be hard on the joints, especially for us older folks.  The landing in a box jump is very soft - remember, you don't fall down onto the box, you just barely catch yourself on it at the top of your jump - and you're free to climb down rather than jumping down if your knees aren't up to a pounding.
  • The primary muscles working to fully extend the hip are the glutes.  And really, who doesn't want nicer glutes?  
I don't think you should totally ignore hip strength in a deep squat - you need to be strong through the entire range of motion of the hip, for safety reasons if nothing else.  But given how rarely you get into a deep squat in combat or sparring situations, you should focus more than half of your hip training to developing that fast snap.  Swings and box jumps are two of the best exercises I know of to do that!  Plus, being able to jump up onto high things is another cool party trick to pull out when people get tired of seeing you do one arm pushups.



  1. I have what we joking refer to as "box phobia." I'm fine at the 16" box, but when I jump (ha, pun) to the 20" box there is a lot of hesitating and false starts. Usually, after 4-5 jumps at the 20" box, I resort to step-ups. Any suggestions?

  2. My first thought is that you shouldn't do more than 4-5 jumps, so what to do after that isn't really relevant. Fear will slow you down and reduce the force output of your jumps - you never want to do jumps when you're fatigued or think you might fall. NEVER do them when you're hesitating and doing false starts. If you think you can do 4, stop after 3. ONLY do a 4th jump if the 3rd one feels really easy and leaves you feeling really confident. If you want to ramp up the work, try jumping higher - jump 22" high and fall down a little onto the box. Do enough of that and you won't be afraid to miss the 5th jump - not if on the 4th rep you cleared the box by 3". Box jumping is not a good method of conditioning - it's not to get you in shape, it's to develop explosive power!