Plyometrics: How Much Is Enough?
Plyometrics is the use of explosive movements to train speed and power. Plyometric exercises such as jumping are valuable to athletes because they improve strength, jump height, and sprinting ability. But knowing how much plyometric exercise volume to prescribe is tricky. Plyometric exercise is taxing to both the body and central nervous system. Too little could be a waste of time, while too much could be a recipe for injury and overtraining.
A recent study from the Journal of Strength and Conditioning Research examined this topic. Researchers wanted to know the response of well-trained athletes to different volumes of plyometric training. Researchers recruited eleven high-level rugby players and put them through a different plyometric training volume each week for three weeks. The low, medium, and high volume plyometric workouts were given in random order. Each workout involved sixteen-inch hurdle jumps in volumes of 100, 200, and 300 jumps.
Before and after each workout, each participant completed a series of jumping tests and gave a blood sample to measure hormonal profile. So which volume of jumps showed the most favorable response? Well, they were all about the same. Each volume of training caused approximately the same testosterone, cortisol, and lactate response. Each volume of training impaired jumping ability the day after training, and by about the same amount. That’s not exactly material that creates gripping headlines - or is it?
For elite athletes, training efficiency is paramount. Each exercise has a purpose, an intended training effect, and a cost in terms of recovery. If we can get the same training effect from a lower volume protocol that athletes will recover from more quickly, then the lower volume protocol makes more sense. This allows the athlete to spend time on other exercises that will give a different training effect, or to recover more quickly so training can be repeated sooner.
The lesson for coaches is to apply the minimum stimulus necessary to get the desired training effect. No more, no less. How do the one hundred sixteen-inch hurdle jumps in this study translate into other plyometric exercises like box jumps, depth drops, and squat jumps at various different heights? Unfortunately, Google returned zero search results for “hurdle jump to squat jump conversion calculator.” I’m kidding, but the question really can’t be answered without further study. One thing is for sure - whatever plyometric exercise you choose or prescribe, consider the total volume and whether it is the minimum required to give the desired training effect.
P.S. If you’d like to learn more about plyometrics, Russian scientist Yuri Verkhoshansky is considered the father of plyometrics, and his book, Supertraining, is one of the pivotal references on the subject.
1. Eduardo Cadore, et al. Neuromuscular, Hormonal, and Metabolic Responses to Different Plyometric Training Volumes in Rugby Players. Journal of Strength & Conditioning Research. Nov 2013. Vol 27. Issue 11. p3001–3010. doi: 10.1519/JSC.0b013e31828c32de.
Photo courtesy of CrossFit Impulse.