Using Tendo Units To Measure Jump Height (Physics Cheat Sheet)

Jump Height and Peak Velocity of a movement are very strongly correlated to one another. Peak velocity at the end of the push-off phase determines your jump height (Impulse – Momentum relationship). Technically speaking, you actually reach peak velocity right before you leave the ground, which means the highest peak velocity that occurs in a vertical jumping movement, say a jump squat, doesn’t actually occur at push off, instead right before. Because of this, technically speaking peak velocity will not give you a 100% accurate measure of vertical jump height. However, neither will a just jump mat or most any field testing tool that doesn’t directly calculate impulse. Which means in this case, reliability is very important and from my own personal work, using peak velocity is quite reliable (there are a couple of studies supporting me too).

 

Remember, peak velocity is going to be used a metric to determine an object’s displacement, in this case a jump height. One issue with peak velocity is that, well, it is peak velocity… As coach knowing peak velocity is cool, but kind of useless unless you have a calculator on hand during a training set… which I really hope you don’t. So, what good is peak velocity?

Well, peak velocity is great, especially for a nerd like myself. I like physics and I like numbers, which means I decided to put together a peak velocity “Cheat Sheet”.

Below is a graph of peak velocity (in this case representing push off velocity) and inches. Again, you can see that its kind of a mess and for the most part, useless in the weight room. However, it does give you quick snapshot of how jump height and peak velocity are not linearly related, which means you cannot just take peak velocity and assume an increase means one to one, linear increase in jump height. 

So, because of the apparent uselessness of peak velocity for acute actionable insight on the weight room floor, I decided to put together a quick “cheat sheet”

Above is the cheat sheet for peak velocity to inches. You will notice the velocities and inches are in ranges. I made it this way so its smaller to carry around and something you can keep in your pocket or stick on the rack. If you want the full card of every inch to velocity metric feel free to shoot me an email or message me on Instagram.

How To Use

Well, every Tendo unit, or bar velocity measuring device will have a peak velocity setting. You can now use these peak velocities to measure jump heights of different movements. If you want to do bw jumps, just have the athletes attached the Tendo to a pvc pipe and place the pvc pipe on your back like you would a squat jump. You could also attached it the front of a lifting belt, but you would need to position the athlete directly above the unit and it may be more of a pain than a use. I suggest the pvc pipe.

Is this going to be perfect? No. Is it going to be a hell of a lot more useful than just having a random peak velocity number without any contextual comparison? Yes.

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