Even though jumping higher in basketball does require the use of weights to reach your maximum potential, there is no reason that you cannot get stronger using only your body weight. The best way to gain inches on your vertical jump without weights is to use your imagination. This requires you to push through pain so that you can reach new heights. If you are fairly strong and feel that some body weight exercises are not challenging you, then you need to start breaking the exercises down to isolate one muscle group at a time. One example of this is to do one leg squats.
When you see them performed, it may seem that one leg squats are pretty easy to do, that is not true, they are quite challenging. The process of the actual squat is basically the same but the twist is what you do with the opposite leg. Always begin with legs about shoulder width apart and feet facing forward. Just as in a regular squat when you lower your body you push your behind out, but as you go lower you will take one leg and push it directly out in front of you, so that it is fully extended.
Always remember that as you squat to keep your knees in line with your toes. This means that the middle of the knee should be in line with at least the third toe on your foot. Never let you knee slide inward towards the other leg or outward. You can really strain the knees and injure yourself if this happens. Another very important point is make sure that you do not push the knee forward while squat putting pressure on the joints. This is why you are to push the behind out as you squat so all the strain is on the thighs and butt. The goal is to squat all the way down until your hamstring makes contact with your calf muscle, then you raise back up and repeat.
To prevent injury it is very important that you do the exercise slowly to emphasize proper technique. Doing them slowly also has the added benefit of stopping you from using momentum to make the exercise easier. It will take a bit of balance not to tip over as you squat down and this uses more muscles to stabilize your body so you are making the squat even more effective.
Beginning athletes as well as experienced athletes can benefit from one leg squats. Your level of strength will determine how many sets and reps that you do. As a beginning athlete you may want to strive for at least two sets of ten or two sets of five. If that is too easy, try doing two sets of burnout (as many as possible) sets. For more advanced athletes you can do three sets of fifteen or three sets of burnouts as well. You can also do squat jumps as well with one leg as you do with two legs. You can even challenge yourself to see how many you can push out with one burnout set.
It is very important to understand that this process is not all fun and games and will take some time and sweat to be successful. Anything worth having is worth working for. If it was easy everyone would be flying through the air dunking with ease. Increasing your vertical jump and dunking a basketball is not an easy thing to do, but if you keep in mind that it will take continued dedication, pushing yourself past your comfort zone, and perseverance when you want to quit, you will reach your goal of dunking.