Box jumps are one of the most popular plyometric exercises. But many people don’t know about the box jump’s bastard cousin, the drop jump. Drop jumps involve stepping off a high platform, absorbing your impact with the ground, and immediately jumping back into the air as high as possible. Drop jumps can be extremely taxing to both the body and central nervous system. In a recent study in the Journal of Strength and Conditioning Research, two researchers, one from Canada and one from Australia, crossed continents to study how leg strength affects drop jumps.
The research team recruited fifteen well trained female rugby players and measured their max front squats. Then the ladies were put through a series of tests using drop jumps. Researchers measured many different qualities of the drop jump, but focused particularly on the jump height.
The researchers used the front squat results to divide the women into a low strength group and a high strength group, depending on their strength-to-bodyweight ratios. Women from the high strength group displayed significantly better performance on the drop jumps. They jumped significantly higher, especially at higher drop heights. At the highest drop heights the high strength group was jumping a full two inches higher than the low strength group.
You may be asking, “So what? The stronger women jumped higher. Big surprise.” But the lesson learned is that leg strength plays a large role not only in plyometric performance, but in tolerating plyometric work. Performance in the low strength group declined rapidly as drop heights increased, while the high strength group was able to maintain about the same jumping height across all drops.
So if you want to improve plyometric performance, then you can’t ignore leg strength. While plyometric work may seem like a bodyweight exercise, and therefore the opposite of moving a barbell, your ability to move a barbell with your legs may limit your plyometric performance.
This study also demonstrates the importance of lower body strength training for athletes. A football player jumps to catch the ball, lands, and then takes off in a different direction – that’s a lot like a drop jump. A basketball player jumps repeatedly to fight for a rebound – that’s a lot like a drop jump. A CrossFit athlete performs rebounding box jumps in competition – that’s a lot like a drop jump. Each of these athletes must excel at jumping, but each must also understand that leg strength is as critical to his success as plyometrics. The two work hand in hand.
1. Matthew Barr and Volker Nolte. The Importance of Maximal Leg Strength for Female Athletes When Performing Drop Jumps. Journal of Strength & Conditioning Research. February 2014 – Volume 28 – Issue 2 – p 373–380. doi: 10.1519/JSC.0b013e31829999af
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