I gave myself six months to dunk because that was the low end of the “six to eight months” prescribed on the website of Brandon Todd, a 5'5" former D-III star who set the same goal for himself in 2005, and then, at age 22, accomplished it. When I first contacted him, Todd perfectly expressed the more shallow reason behind my goal: “When you can dunk, it means you’re a good athlete. Period. It takes away any subjectiveness.” I also chose six months because, as would be proved repeatedly during this mission, I am prone to tragic spells of overconfidence.
Start with a ping-pong ball, then a tennis ball, then a softball, then a volleyball, then a youth-sized basketball, and on up until you can dunk with a regulation size ball. If you can't palm the ball, then you will need to learn how to control the ball with two hands until the last minute extension for the dunk with one hand, or you will have to jump high enough to dunk two-handed.

Vertical jump training and assisted vertical jump training (essentially with a negative load) can each increase vertical jump height through increases in countermovement depth, even while actually reducing peak force produced in the jump. This seems to happen because the tendon becomes more compliant after these types of training, which means they elongate more during the countermovement phase of the jump.
I followed the Jump Attack program to the letter, and my training in December, January and February looked and felt nothing like what had preceded it. I spent a month doing those nonsensical lunge holds (and squat holds, push-up holds, chin-up holds). I trusted those holds, and the tendon-testing leg workouts that lasted 2 ½ hours and left me tasting my own broken down muscle in my mouth. I trusted all of it because I was living in that moment, as Carter put it, when the hammering of Carter’s “muscle memory” into my body finally would bear fruit and I’d pitch the ball downward into a 10-foot hoop like a cafeteria customer dunking a roll in coffee.
Dunking exposes you to some extra risk of injury. First of all, you can get low-bridged or get your legs tangled up with defenders near the hoop, causing you to fall awkwardly from a significant height. You can also throw yourself off balance by trying to hang on the rim and slipping off, resulting in awkward falls. If you are in heavy traffic on the dunk, then being able to grab and hang on the rim until the clutter beneath you clears is a safety technique. If you are in the clear on a dunk, then avoiding hanging on the rim at all is the recommended safety technique (It's also a technical foul to hang on the rim in that situation). Whatever the situation, you need to come down with control and balance. Ankle, knee, neck, and head injuries await those who fail to control their momentum after a dunk.
The between-the-legs dunk was popularized by Isaiah Rider in the 1994 NBA slam dunk contest,[12] so much so that the dunk is often colloquially referred to as a "Rider dunk" — notwithstanding Orlando Woolridge's own such dunk in the NBA contest a decade earlier.[13] Since then, the under-the-leg has been attempted in the NBA contest by a number of participants, and has been a staple of other contests as well. Its difficulty — due to the required hand-eye coordination, flexibility, and hang-time — keeps it generally reserved for exhibitions and contests, not competitive games. Ricky Davis has managed to complete the dunk in an NBA game,[14] but both he[15] and Josh Smith[16] have botched at least one in-game attempt as well.
Because jumping ability is a combination of leg strength and explosive power, jumping can be developed in the same fashion as any other muscular activity. The ultimate limit to how high any athlete can jump will be determined to a significant degree by the distribution of fast-twitch versus slow-twitch fibers present in the muscles of the legs. This distribution is a genetic determination. Fast-twitch fibers are those whose governing neurons, the component of the nervous system that receives the impulses generated by the brain to direct muscular movement, fires more rapidly, which in turn creates the more rapid muscle contractions required for speed. As a general proposition, an athlete with a greater distribution of fast-twitch fibers will be able jump higher than one with a preponderance of slow-twitch fibers.

Other binary end points were analyzed with the use of chi-square tests, and continuous variables were compared by means of an unpaired Student's t-test or a Wilcoxon rank-sum test, as appropriate, with the use of SPSS software, version 13.0 (SPSS). All reported P values are two-sided and have not been adjusted for multiple testing. The study statistician and investigators remained unaware of the patients' treatment assignments while they performed the final analyses.

Vertical jumps are used to both train and test for power output in athletes. Plyometrics are particularly effective in training for power output, and include vertical jumps of different types in their protocol. In one recent study, training with plyometrics (which included continuous vertical jumps) was shown to improve jump height and boost vertical jump performance to similar degrees in combination with very different resistance training protocols, indicating that the plyometric jumping contributed to the increased jump height more than resistance training. Research into plyometric jumps found vertical jumps to be among the highest in terms of muscle recruitment (as measured by electromyography), power output, and ground reaction force produced.[8][9][10] Fatigue has been researched in athletes for its effect on vertical jump performance, and found to decrease it in basketball players, tennis players, cyclists, rugby players, and healthy adults of both genders.[11][12][13]