During the 1940s and 1950s, 7-foot center and Olympic gold medalist Bob Kurland was dunking regularly during games. Yet defenders viewed the execution of a slam dunk as a personal affront that deserved retribution; thus defenders often intimidated offensive players and thwarted the move. Satch Sanders, a career Boston Celtic from 1960 to 1973, said:
Perhaps the most popular obstruction-modified dunk is the Dubble-Up. Aptly eponymous of the its pioneer—T-Dub, an American dunker hailing from Minnesota—the Dubble-Up starts with a person standing before the basket, holding the ball above their head. The dunker approaches and leaps as though their groin would soar above just above the head and their legs around the stationary person. Just prior to clearing the person, the dunker will assume control of the ball with one or both hands, guide it under a raised leg, transferring it to the appropriate hand, clearing the ball-holder, raising the ball above the horizontal plane of the rim, and finally guiding it downward through the basket. While the Dubble-Up mimics a between-the-legs dunk, Kenny Dobbs and Justin Darlington have both performed an under-both-legs variant.
We conducted this multicenter trial between December 19, 2003, and October 6, 2007, in eight centers in Belgium, Austria, and Spain. All patients 18 years of age or older in whom a vasopressor agent was required for the treatment of shock were included in the study. The patient was considered to be in shock if the mean arterial pressure was less than 70 mm Hg or the systolic blood pressure was less than 100 mm Hg despite the fact that an adequate amount of fluids (at least 1000 ml of crystalloids or 500 ml of colloids) had been administered (unless there was an elevation in the central venous pressure to >12 mm Hg or in pulmonary-artery occlusion pressure to >14 mm Hg) and if there were signs of tissue hypoperfusion (e.g., altered mental state, mottled skin, urine output of <0.5 ml per kilogram of body weight for 1 hour, or a serum lactate level of >2 mmol per liter). Patients were excluded if they were younger than 18 years of age; had already received a vasopressor agent (dopamine, norepinephrine, epinephrine, or phenylephrine) for more than 4 hours during the current episode of shock; had a serious arrhythmia, such as rapid atrial fibrillation (>160 beats per minute) or ventricular tachycardia; or had been declared brain-dead.
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.