I write about plyometrics often. One of my popular postings deals with the Depth Jump, the cornerstone exercise for athletes seeking a better vertical jump.
RELATED: Box Jumps: Are They Really Worth It?
Reflexive Box Jumps
There comes a time, however, when Depth Jumps fail to provide a piece of the athletic performance equation that many athletes really need: reflexive speed. Athletes can find this with Reflexive Box Jumps.
What is "reflexive speed?" It is the ability of the nervous system to powerfully and rhythmically coordinate movement with ground contacts under .15 seconds. In other words, it is the fast and coordinated movement that allows rapid sprints, cuts and jumps on the field of play.
What research has shown is that weight room work can build strength that is used in athletic feats that have ground contact times of over .20 seconds (think a maximal jump of 2 feet), but anything that is .15 seconds or less, the weight room can't directly help. What are some athletic feats that happen in under .15 seconds?
- Making a reactive step to an opponent's movement
- Anything beyond the first 10 yards of acceleration in sprinting
- A very quick jump, such as a quick hop to block a shot, or a long jump takeoff
In addition, athletes who are faster and more powerful than they are strong (think those who can bound and jump better than they can sprint fast), need to include a good portion of "reflexive firing" plyometrics in their program to help them produce more force in less time. Most traditional plyometrics don't cut it, because the contact times are too long. This is something I learned from two great coaches, Dan Fichter and Chris Korfist.
Bottom line, if you are more powerful than you are fast, you need to be looking at plyometrics that help you store and release energy faster.
A simple but effective method of increasing rate of force development is the Reflexive Box Jump. This move has gone by many names through the course of sports performance training, but in many cases, it is not properly performed, which hurts its effectiveness and destroys its ability to improve the ability of an athlete to improve that ".15 second or less" force development.
When correctly performed, Reflexive Box Jumps can vastly improve an athlete's force transfer patterning in vertical jump movements. They can also help create vertical stiffness in sprint ability—and do so in a more specific manner than Depth Jumps alone.
So how is the movement correctly performed? Below is a video showing how to perform a Reflexive Box Jump, and how it differs from a traditional Box Jump.
- Use a box below 18 inches in height.
- Focus on driving your feet back down toward the ground as rapidly as possible, coming off the top of the box.
- Minimize ground contact time, and get back up to the top of the box as fast as you possibly can.
Performing Box Jumps in a manner where you jump up, causally drop back down and then jump back up again is a very ineffective way to perform repeat Box Jumps. The technique that makes the Reflexive Box Jump stand out is that it is done with minimal rise of the hips. Something that can help this function of the Jump to improve automatically is to count the number of reps an athlete can accomplish in a set time period, such as 10 seconds. This ideal plays off "Parkinson's Law," which suggests that we are wired to get more work done when time is set as a constraint, rather than just a number of reps we need to do.
The Reflexive Box Jump is one of the best movements available for pairing with various strength exercises, or as part of a French Contrast series. One of my favorite contrast series involves the Reflexive Box Jump as one of the plyometric exercises—on an 18-inch box if it's the first exercise, or a 8- to 12-inch box if it's the second.
I recommend starting with a 12-inch box for the majority of athletes, eventually moving up to an 18-inch box. Athletes who can perform the Reflexive Box Jump quickly and efficiently on an 18-inch box will generally possess great vertical force qualities in sprinting and reactive jumping ability.
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