Nike+ Basketball measures vertical jump by using a precise measure of the time you're in the air, determined by the Nike+ Pressure Sensors in your shoes.
The physics behind jumping tell us that once you know your time off the ground, we can calculate your vertical. Regardless of whether you jump off one foot or both feet, standing still or running, Nike+ Basketball can determine your vertical every time you leave the floor.
Vertical jump measurements are based on the difference in how high you get your center of mass from a normal standing position to the peak of your jump, not how high you can get your feet.
Since vertical measurement is primarily based on the time off the ground, there are some common scenarios that may occur as you play that can skew the reported measurement, including hanging or pulling on the rim, or leaning into or landing on another player.
For the most accurate vertical measurement with Nike+ Basketball, jump and land on the same surface, land with your legs slightly bent, and do not touch anything in the air.
Note: The Nike+ Basketball App is no longer available for download in the iTunes App Store. If you are an existing user with the app already downloaded and installed, you can continue to use the app as you've done in the past. Be aware that if you have the Nike+ Basketball App installed and upgrade to iOS 8, you will no longer be able to use the app, as it isn't compatible with iOS 8. For more information, please click here.