This is a guest post by Andreas Rauh. He writes about basketball and vertical jump training on, and also documents his vertical jump training on his Youtube Channel.

At 6ft tall, I was always a pretty athletic basketball player, I could grab the rim easily and on a really good day (and on lower rims) I could even squeeze in a dunk from time to time. But in the summer of 2015 I decided to go for it, I wasn’t getting any younger and I wanted to know just how high I could jump if I really worked hard on it. And so my obsession with vertical jump training began!

I am a firm believer in this quote: “Only what gets measured gets improved” and so I knew that I wanted to keep track of my vertical jump height during the training. But that turned out to be harder than I thought…

There are many different ways that you can measure your vertical jump.

The easiest method is grabbing a piece of chalk and trying to mark the highest point you can reach by jumping against a wall. But this method is rather inaccurate, and totally useless if you want to measure your running jump.

A very professional way to measure your vertical jump that is used by many colleges and the NBA draft combine is the so-called Vertec, a large pole that has smaller, movable horizontal vanes attached to it. If used correctly, this apparatus is very accurate and easy to use. But it is also expensive (there are tutorials on how to build your own) and impractical due to its size.

Another possible way, that is often used in scientific research is the force plate analysis. A Pressure-sensitive platform records the ground reaction forces that the athlete exerts each millisecond during the vertical jump and then uses this data to calculate the vertical jump height. This is made possible by some basic laws of physics that tell us that there is a direct relationship between hang time and jump height.

Back to my story: I am definitely a bit of a geek, but paying hundreds of dollars for such a force platform just wasn’t feasible…

The method of the force plate analysis, however, taught me that if we could somehow measure the hang time of a jump, it wouldn’t be difficult to calculate vertical jump height at all! And so I started to work on the “What’s my Vertical” app.

For years now, the iPhone has been able to record 240fps video, that is video which consists of 240 unique images per second. Cameras that are able to do this used to cost thousands of dollars, but now everybody that owns a modern smartphone can shoot incredible slo-mo videos. So if we shoot a video, tag the exact moment of takeoff and landing, we are able to accurately measure the hang time of a jump!

And that is exactly what the “What’s my Vertical” app does:

So now, you can measure your vertical with these four easy steps:

  1. Use the camera of your iPhone to shoot a high frame-rate video of a vertical jump.
  2. Open the “What’s my Vertical” app and load the video you just recorded
  3. Skip to the moment of the video where your feet are just leaving the ground and press the button “Set Takeoff”
  4. Further forward the video to the moment where your feet are first touching the ground again and press “Set Landing”

That’s it! The app now calculates the difference in time between the takeoff and landing (the hang time) and tells you the corresponding vertical jump height!

You just want to make sure that you don’t artificially increase the hang time by hanging on the rim or landing in a very deep crouch, as this would falsely increase the calculated vertical jump height. If you regard these rules then this type of vertical jump analysis is incredibly accurate, in fact, there have been scientific studies that prove the accuracy of the method!

The “What’s my Vertical App” is now available for free on the Apple App store here.

An Android version is planned for later this year.