Vertical jump on force plates – A short guide to the output you can expect from using sports tech like force plates
As we have teased, one of our upcoming products will be force plates. Force plates are versatile sports tech devices that you can use for many different exercises, but the most common one is the vertical jump.
Before you decide to buy a force plate, we want to help you understand the data you can get from testing vertical jumps.
A vertical jump has three main phases: preparation, propulsion, and flight (The Physics of the Vertical Jump – Topend Sports, n.d.; The Physics of the Vertical Jump – Force, Speed, Height, Hangtime & Co, n.d.; Biomechanics of a Vertical Jump by hannah martin-spencer, 2018).
The vertical jump illustrated with the force curve output from force plates
To help you visualise the phases and the force graph, we have created the infographic below. Please note that the actual graph you get will be less smooth, as this is just an ideal theoretical example:
The phases of the vertical jump
The preparation phase is when you bend your legs and swing your arms back to get ready to jump and lower your body. (The Physics of the Vertical Jump – Force, Speed, Height, Hangtime & Co, n.d.). On the force graph, you can see that the force goes down in this phase because your body’s centre of gravity is lower than when you are standing still.
The propulsion phase is when you straighten your legs and swing your arms up to push off the ground and go up in the air. This phase involves moving your hips, knees, and ankles one after another (Biomechanics of a Vertical Jump by hannah martin-spencer, 2018). The more force and speed you create in this phase, the higher you will jump (The Physics of the Vertical Jump – Topend Sports, n.d.).
The flight phase is when you are off the ground and reach the highest point of your jump. The flight phase has two parts: ascending and descending. The ascending part is when you are still going up until you stop at the top of your jump. The descending part is when you start falling down until you touch the ground again. The length of the flight phase depends on how fast you were going up and how fast gravity pulls you down (The Physics of the Vertical Jump – Topend Sports, n.d.; The Physics of the Vertical Jump – Force, Speed, Height, Hangtime & Co, n.d.). The time in the air can be called time of flight or hang time. Note that the force on the ground will be zero in this phase.
In the landing phase, the force will be high at first – or almost as high as the peak force in the propulsion phase (depending on how much air resistance and other things slowing you down). Then you will bend down again to make the landing softer and then stand up and go back to your normal position.
We hope this will help you understand the data you can get from using force plates. Force plates can help you measure not only the vertical jump, but also other exercises such as squats, deadlifts, launches, handstands or pushup. You can use them to analyse your performance objectively in any exercise you can imagine. And don’t worry, we will keep you updated on our blog with more ideas on how to use our sport tech devices.
References
Biomechanics of a Vertical Jump by hannah martin-spencer. (2018). Prezi.com. https://prezi.com/mx_5tldwc0_8/biomechanics-of-a-vertical-jump/
The Physics of the Vertical Jump – Force, Speed, Height, Hangtime & Co. (n.d.). Thehoopsgeek.com. Retrieved March 27, 2023 from https://www.thehoopsgeek.com/the-physics-of-the-vertical-jump/
The Physics of the Vertical Jump – Topend Sports. (n.d.). Topendsports.com. Retrieved March 27 2023 from https://www.topendsports.com/testing/vertical-jump-physics.htm
