Don't do jumping exercises 7 days a week. Four or five days per week is enough. If you do it every day, you may give up after a week or two. The idea is to keep exercising for months, or years, consistently. Note that we have not organized an actual jumping program. Inside Hoops is providing exercises that should help your fitness and leaping ability.
Before starting the exercises, warm up your muscles. Stretch properly, and jog around for a few minutes.
If you have a jumprope, use it. Jumping rope definitely helps your conditioning.
Running up and down stairs for a while is very useful as a warmup, or a full exercise. Don't do too much or else you may wear our your legs. Use it as a quick warmup, or a full exercise.
Deep Knee Bends --- Be standing. Slowly bend at the knees while keeping your back straight. Slowly crouch down as low as possible (it shouldn't hurt) and slowly rise back up. Do this 15 times. Over time increase to 20, 30, etc.
Deep Knee Bend Jumps --- Be standing. Crouch down as described above but fairly quickly, almost touching your bottom to the ground, then explode upwards as high as you can. The moment you land, immediately crouch and launch back up again. Do this 15 times, and when you can, increase to 20, 30, etc.
Toe Raises --- Stand regularly, then raise up onto the tips of your toes. Lower back down. Don't just rock up and down, do it slowly (not too slowly) but steadily. Repeat 30-50 times.
Toe-Raise with Weights --- If you have any sort of weights, holding/wearing them while doing these toe raises will help. Use small weights (a mere 5 or 10 pounds is fine) and work your way up.
Stomach Crunches --- We believe that sit-ups are bad for your back. Stomach crunches, where while lying on your back, using your ab muscles and keeping your back straight, you rise up just enough to lift your shoulders off the ground, are better. Do them often - perhaps for 10 minutes in the morning and 10 minutes at night.
Jumping Rope--- Jumping rope definitely helps your vertical leap. Jump rope while watching tv or something. Make it a habit.