The CrossFit Open is coming around again, and that means we’re going to see a lot of burpees and a lot of box jumps. With the ever looming potential for achilles injuries, we’re going to see a lot of people lambasting the use of rebounding box jumps. Last year, everyone jumped on the programming of Open WOD 13.2:
10 mins, as many rounds as possible of:
- 5 shoulder to overhead, 115 lbs for men, 75 lbs for women
- 10 deadlifts, same weight
- 15 box jumps, 24 in for men, 20 in for women
I have to say, I was really proud watching how many people at the gym where I coach taking the initiative to step down from the boxes, rather than "buck up" and do ten minutes of bounding box jumps. Many even switched to stepping up and down for each rep. They were able to move at a steady pace through the workout, get a great cardiovascular punch, and save their achilles tendons.
So what's the deal with plyometrics and how should one use them in training?
Plyometrics is about training the stretch-shorten cycle (SSC), or stretch reflex, to strengthen muscles, increase agility, power, and supplement conditioning work. Notice I said supplement conditioning work. Plyometrics in and of themselves, even though they can get your heart pounding, aren't meant to be used as conditioning moves.
Jumping up on a box is the first, basic level of plyometrics. It starts with a quick drop into a partial squat, a countermovement of the arms, and explosion off the ground onto a platform. The training goal here is to get the athlete to turn their energy around quick, from the drop to lift off. You often see untrained individuals do a slow descent or even a pause at the bottom of the partial squat because this motor pathway and engagement of the SSC has never been trained or tapped into. It's like you can almost see their motor units turn on one by one at the bottom...
What you see in CrossFit, the bounding box jumps, is akin to depth jumps. There are a lot of progressions that coaches and trainers familiar with plyometrics take their clients through to prepare them for depth jumps, not the least of which is dropping from a lower platform and jumping onto a slowly increasing target platform.
The key to proper depth jump technique is watching the heels on the ground. Does the athlete's heel barely kiss the ground or not touch at all? Is the turn around quick? Then the athlete is well suited for the height of the depth jump.
But on the other hand, does the athlete take more than a split second to make the turn around? Are the heels coming in full, sustained contact with the ground? And even worse, does the athlete seem to land flat footed? The depth drop is too high.
Here's what I'd like to see for progressions in CrossFit boxes:
Obviously, start athletes out with stepping down until they demonstrate that they can proper engage and recruit power from through the SSC and countermovements in the jump.
Then, and I know this will slow people's WOD time down, but they should suck it up, have them drop from a lower box or even a stack of plates and jump up to their target box. Watch their heels and their turn around time. As they become more proficient at it, the initial depth drop height can be increased until they're ready for bounding from and jumping to the same box.
And of course, proper care of your achilles is going to go a long way!
This article is courtesy of of Kristin Newman. Kristin is a Strength and Conditioning coach based in California, who also competes nationally in Olympic Weightlifting, Power Lifting, and Strongman. She holds CrossFit certifications in Power Lifting as well as Movement and Mobility. Kristin uses her vast experiences as an athlete and coach, along with her infectious personality to create some of the most interesting and entertaining fitness/health blogs and social media posts. Be sure to check out her blog and follow her on Instagram.