To begin, go up without a ball first. This will give you a great idea of where you’re at and just how close you are to being able to dunk. For beginners, you should focus on dunking with one hand. Your other hand should stay by your side to balance your body while you’re in the air. The two-handed dunk is awesome, but is surprisingly more of an advance dunk and should be an approach you build up to as you work on your dunking.
Other investigators and participants in the trial are as follows: R. Kitzberger, U. Holzinger, Medical University of Vienna, Vienna; A. Roman, Centre Hospitalier Universitaire St. Pierre; D. De Bels, Brugmann University Hospital; S. Anane, Europe Hospitals St. Elisabeth, and S. Brimioulle, M. Van Nuffelen, Erasme University Hospital — all in Brussels; M. VanCutsem, Centre Hospitalier Universitaire de Charleroi, Charleroi, Belgium; J. Rico, J.I. Gomez Herreras, Rio Hortega University Hospital, Valladolid, Spain; H. Njimi (trial statistician), Université Libre de Bruxelles, Brussels; and C. Mélot (independent statistician and physician responsible for conducting sequential analysis and evaluation of serious adverse effects), Erasme University Hospital, Brussels.
A second, more efficient and correct method is to use an infrared laser placed at ground level. When an athlete jumps and breaks the plane of the laser with his/her hand, the height at which this occurs is measured. Devices based on United States Patent 5031903, "A vertical jump testing device comprising a plurality of vertically arranged measuring elements each pivotally mounted..." are also common. These devices are used at the highest levels of collegiate and professional performance testing. They are composed of several (roughly 70) 14-inch prongs placed 0.5 inches apart vertically. An athlete will then leap vertically (no running start or step) and make contact with the retractable prongs to mark their leaping ability. This device is used each year at the NFL scouting combine.