Social media is a great tool, but can often mislead the masses, especially when it comes to training. You see a picture or video and assume the person posting the content has mastered a training principle or philosophy.
One of the biggest examples is the Box Jump. There are countless videos where people are box jumping upwards of 60 inches! These posts look great but what do they really accomplish other than showing a personal best and garnering a lot of views. It’s great that they got a PR, but what do box jumps accomplish as a training tool and assessment, especially when it comes to youth population.
Why Do We Jump on Boxes?
Box jumps are a staple plyometric exercise. For those that are not familiar with plyometric training, here is a basic breakdown.
Plyos for short — is a type of exercise that trains muscles to produce power (strength + speed). Plyometric exercises involve a stretch of the muscles, immediately followed by a contraction of the same muscles-often referred to as the stretch-shortening cycle.
Sports movements such as sprinting, jumping, cutting, bounding, and leaping are all plyo activities. The faster an athlete executes these movements than the opponent, the greater an athlete’s advantage.
Plyometric training can improve an athlete’s stretch-shortening cycle, improve strength, increase joint stiffness, and improve overall jumping ability, which transfers into game moments.
What Do Box Jumps Accomplish?
As previously mentioned, plyometric movements utilize the stretch-shortening cycle and the faster you can execute the cycle the more power an athlete will produce to jump higher or cut quicker. Muscles are eccentrically loaded with an external force (usually body weight multiplied by the acceleration of gravity and momentum from the preceding movement). Then the muscle applies enough force to create a change in the direction of momentum (the isometric phase). Then finally the athlete uses the momentum from the impulse to accelerate through a concentric muscle contraction and create a force as rapidly as possible to apply all the combined forces against eh external load (i.e. gravity).
A simple example of this is the countermovement jump. The athlete creates a movement by crouching down from a standing position and counters the movement by creating an impulse somewhere in their squat and redirects their momentum upwards to propel their body as fast and hard as possible to get maximum height in their jump.
Standing in place, crouching down and exploding into the air is a simple way to execute the stretch-shortening cycle but can cause additional stress to the joints if repeated often. Adding a box helps elevate the landing stress, allowing the athlete to focus specifically on the jump mechanics. In addition, landing on an elevated surface, allows an athlete to execute more quality repetitions as the muscles spend less energy absorbing the landing.
Does Box Height Play a Big Factor?
Let’s get straight to the point, jumping on a higher box is not a clear-cut barometer that an athlete has jumped higher.
The height of any person’s jump does not depend on a box. No matter the object in front of you, the height of an athlete’s jump is determined by how high their center of mass gets from the starting point (ground).
The box height is a set number, while each athlete has different factors in play that affect how high they can jump. For example, an athlete who is tall and weighs less needs less force production than a shorter, heavier athlete. The taller athlete has a higher center of mass than the shorter athlete, and the shorter athlete has a longer distance to travel and more resistance (body weight) to overcome.
So, What Does Box Height Really Mean?
If you cannot land on the box in the same position that you initiated the jump from, the box is too high.
If the athlete’s goal is to land with feet spread, hips in deep hip flexion, and a rounded back, then that high box is for them. In sports, these types of movements never actually occur. As mentioned, your center of mass reaches a peak height, the key is to reproduce similar movements immediately after landing.
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