Have you been drilling single unders until exhaustion in hopes of finally getting double unders? All those singles may not be moving you much closer to your goal, according to an upcoming study in the Journal of Strength and Conditioning Research.

 

Researchers studied 76 young men who casually trained two to three times per week. Each man could perform both single and double unders. Researchers measured jumping characteristics like ground contact time and jump height.

 

So how did the singles compare with the double unders? Double unders showed only marginally less ground contact time than the singles. However, participants jumped twice as high during double unders.

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Then again, everyone jumps higher during double unders, so what's the big deal? The fact that participants jumped twice as high during double unders using a jump very much like the one they used during singles means that the double under jumps engaged the jumping muscles in fundamentally different ways.

 

Think about it this way. Imagine starting your car, putting it in drive, and pressing the accelerator halfway to the floor. You accelerate at a particular rate. Imagine that now you perform the same drill but press the accelerator just a little more. You’d expect to accelerate just a little faster, right? No, this time the acceleration pins your head to the seat, feeling like you’re in a racecar. This isn’t normal, and it means something new was at work during the second trial. Something engaged during the second trial that just wasn’t there the first time.

 

Part of this phenomenon is the stretch-shortening cycle, or SSC. The SSC means that your muscles contract more forcefully after being stretched by a load. The SSC is the difference between performing a normal bench press that springs off your chest and performing a bench press that requries you to pause for two to three seconds on your chest before pressing it. The former uses the SSC, whereas the latter does not.

 

It appears that the SSC is particularly prevalent in double unders. Therefore, if you wish to learn double unders then you must start training the jumping pattern that enables them, including the stretch-shortening cycle. One way we do this at my CrossFit affiliate is by not necessarily scaling athletes back to singles during a workout if they can’t yet perform double unders. If an athlete has a solid command of singles but cannot perform a double under, then hundreds of singles will not bring them any closer to that goal.

 

So what do we prescribe for these athletes? Double under attempts. If a workout calls for rounds of thirty double unders, I might prescribe ten double under attempts for this type of athlete. Yep, I don’t care if they make the double under or not - they just give me ten of their best attempts. Of course, the athlete will still need coaching on jumping mechanics and wrist speed.

 

This method has worked very well for us. After all, if an athlete attempts his first double under once a month, how likely is he to achieve it? What if he attempts it multiple times per week because the attempt is part of his workout? Now he’s far more likely to achieve success.

 

References

1. Kazuyoshi Miyaguchi and Shinich Demura. Possibility of SSC training using a jump rope. Journal of Strength & Conditioning Research (forthcoming). POST ACCEPTANCE. 15 July 2013. doi: 10.1519/JSC.0b013e3182a0c9a5

 

Photo courtesy of CrossFit Impulse.

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