IR - it determines your OwnZone by taking you through a classic fitness test. Once you've done the test you don't need to retake it for a while and it sets all the sports zones for you.
There are other ways of obtaining the data needed for determining your training zones. The OwnZone test is suitable for people who are not used to strenuous exercise but it works just fine anyway; on one of our courses we performed a comparison (Cooper, the walking and jogging OwnZone test, and also the three minute hill test) on a motley bunch of runners including a sub 2:20 marathoner, a sub 13 minute 5 k guy, a complete beginner, and a sub 4:30 marathoner, 25 people in all, and the results were strikingly consistent (though of course across a very wide range).