During the takeoff an athlete generates forces that ultimately result in a vertical velocity high enough to leave the ground. We have shown before, that this vertical velocity reaches 0 at the peak of the jump, and it is easy to show that the velocity is exactly the same during landing as it was during takeoff (but directed in the opposite direction).
Stand on the bottom step of a flight of stairs holding the railing on either side. Place the balls of your feet on the stair with your heels hanging off the edge. Slowly raise your heels as high as you can, and hold for two seconds. Slowly lower your heels below your toe level, and hold for two seconds. Repeat calf raises exercise 20 times for three sets with a 1-minute break between each set.
Ok I just turned 18 2 months ago and I'm 6,2 and weigh about 155 and I'm very athlectic I've played basketball ever since 3rd grade so I'm very familiar with tecniques and fundamentals I don't play as much as I used to but I can still get rim on my thumb no prob but can't dunk.what can I do bc I wanna jam on my bro. Also being noted that I've dunked about 2 Times but were sloppy plz help
I think one way of thinking about it is, less parts of the body, and more the kind of muscle. You want to develop your quick-twitch, or fast-twitch, muscles, because at the end of the day, trying to dunk a basketball is an explosive activity. You’re not going for a long-distance run here. You’re doing three quick steps, a hard shove against the ground, and exploding upwards. So the question is how to turn yourself into basically a sprinter. You do a lot of jumping exercises where you’re doing box jumps, where you jump off one box and as soon as you hit the ground, you try to jump up onto another box. That sort of thing.

The first thing they have to do is improve their flexibility, for a couple of reasons. They need to be flexible to undertake the kind of exercises they need to be able to jump higher. They also just need to be able to increase their flexibility, because in the short sprints you take when you try to dunk a basketball, if you can imagine yourself running up to try to dunk on the rim, the higher you can bring your knees in a sprint, just like a sprinter running the hundred meters, the greater force you’ll be able to exert on the ground, especially with your leaping step.
There are a number of variations on the windmill, the most common being the aforementioned one- or two-hand variants. In these cases, the windmill motion may be performed with the previously discussed one-arm technique and finished with one- or two-hands, or the player may control the ball with two hands, with both arms performing the windmill motion, finishing with one or both hands. Additionally, the ball may be cuffed between the hand and the forearm—generally with the dominant hand. The cuff technique provides better ball security, allowing for a faster windmill motion and increased force exerted on the basket at finish, with either one or both hands. Using the cuffing method, players are also afforded the opportunity of performing the windmill motion towards the front (counterclockwise), a technique exploited by French athlete Kadour Ziani when he pioneered his trademark double-windmill.
Though improving jumping technique may add a couple inches to an athlete's vertical jump, good landing technique is even more crucial. The landing is when almost every jumping-related injury occurs, not the jump itself. For this reason, athletes should spend a significant amount of time learning to land in a balanced position that distributes the impact of the jump equally across all joints of the lower body. This position should look almost identical to the take-off position.

IMPORTANT NOTE: Feb 2, 2019 - I am currently updating the site to have all the articles on the same format and also shooting new HD videos of the exercises in the library. For the duration of the this update I am selling Game Changers at an 80% discount (YES YOUR READ THAT RIGHT - 80% OFF the regular price). Instead of paying $47 you can pick up a copy of just $9. But hurry - this offer will be gone once I finish the updates.
Keep your upper body straight and your arms relaxed at your side. Extend your left leg straight out behind you with a slight knee bend. Place your right leg in front of you with your knee bent at a 90-degree angle and your thigh parallel to the floor. This is your basic lunge position. From this position, slightly lower your entire body, and jump to the opposite lunge position with your right leg extended behind you and your left leg in front of you. Repeat 25 jumping lunges in a row for three sets with a 1-minute break between sets.
The dose was determined according to the patient's body weight. Doses of dopamine could be increased or decreased by 2 μg per kilogram per minute and doses of norepinephrine by 0.02 μg per kilogram per minute (or more in emergency cases) (see Figure 1 and Figure 2 in the Supplementary Appendix, available with the full text of this article at NEJM.org). An example of the dose-escalation table is provided in Table 1 in the Supplementary Appendix. The target blood pressure was determined by the doctor in charge for each individual patient. If the patient was still hypotensive after the maximum dose of either agent had been administered (20 μg per kilogram per minute for dopamine or 0.19 μg per kilogram per minute for norepinephrine — doses that have been shown to have similar effects on mean arterial blood pressure12,13), open-label norepinephrine was added. The dose of 20 μg per kilogram per minute for dopamine was selected as the maximal dose because this upper limit was the standard of care in the participating ICUs, in line with expert recommendations14 and international guidelines.15
Asher Price, a reporter at the Austin American-Statesman, spent a year of his life trying to find out and chronicled his quest to jam on a regulation hoop in the book The Year of the Dunk, which comes out in May. Price, who played coy about whether he was able to achieve his goal, spoke to Science of Us about what a rec leaguer would need to do to fly like a pro. (Spoiler: lots of squats and alley-oop attempts.)

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.