One way to build the muscle groups used during basketball play, including muscles used to jump and run, is to wear a basketball weight vest. In such a vest, your body, while employing the same muscle groups, is forced to work harder to make the same moves and reach the same heights. This may lead to quicker movement and higher jumps when the vest comes off.
Select a vest that fits. Some vests come in the one-size-fits-all variety, but try them on anyway. The vest should be snug, but not too tight and definitely not too loose.
Adjust the weights in the vest. A typical basketball weight vest will fit anywhere between 25 and 150 lbs. of weights. Begin with the former amount; you needn't practice with 80 lbs. to see results. Adding 25 lbs. is adding a lot--and may be all it takes. Weights generally fit into pockets on the vest, held tight by straps or velcro.
Slip the basketball vest over your head.
Tighten the vest around your back and hips using the vest's straps. These usually tighten via velcro, buckle or a combination of the two. Some weight vests have multiple straps, some have just one. The vest should be snug, but not too tight (you don't want it digging into your skin). If it's too loose, though, it may chafe your skin.
Undertake your regular practice regimen. The weight vest will add extra challenge to your practice sessions, of course, but such vests are designed to be worn during play. That's the point: to work the muscle groups you normally use during actual play.
Add weight, as desired. Over time, you may find that 25 lbs. isn't as challenging as it once was.