Last week my good friend and frequent writing partner, Joe Giandonato, sent me an email that got me thinking. Joe had gone back through his training logs, the logs of his clients and even examined the numbers of NFL combine participants in the years past and he found something very interesting. He found that a given athlete’s vertical jump is about 70% of their box jump height. Oh, word?
Of course, this motivated me to check back through my logs and those of my clients. Not surprisingly, Joe was on to something! The majority of the logs I checked, including my own, lined up pretty perfectly with what Joe had found. But, just to be sure Joe referenced another classmate of ours, Josh Bryant of joshstrength.com. Josh had this to say, “I would say you are pretty right on. If someone had asked me, having not looked at the numbers or analyzing the data, I would have said 2/3 which rounded up would be 67%, I think you are dead on. Glad you brought this up although it will vary but good athletes with a reasonable amount of flexibility you are dead on.”
Josh’s comment on flexibility is spot on. I’ll go even further to say that over-all lower body mobility plays a big role in the comparison. Box jumps are not only an expression of power, they are also an expression of mobility. Guys with great box jump numbers by and large have great hip and ankle flexion mobility. A “stiffer” athlete may have great explosion off of the floor, but without great range of motion at the hip and ankle he or she won’t be doing anything impressive with box jumps.
So, what’s the point in comparing these two? Well, if you can jump on a 50″ box you have a pretty good idea that your vertical is around 35 inches; which can help in planning training. In another line of thinking, if the gap is smaller between a given athlete’s box jump PR and vertical jump PR it might be an indicator that they need some hip and ankle mobility work.
Thanks to our good friend Joe Giandonato, we all have one more angle of comparison and assessment for programming power training for athletes and ourselves.
If you want to learn more about and from Josh Bryant, check out his training log here or go to joshstrength.com. Josh also has a comprehensive training e-book that he co-authored with Brian Dobson entitled Metroflex Powerbuilding Basics. It’s definitely a resource you want in your library. Pick up your copy here.