The RDL (Romanian Dead Lift) exercise is going to help to build strength in the players lower back, glutes, and hamstrings. These muscle groups are where a lot of the jumping power comes from, especially when jumping off of two feet. So this exercise is really good for improving a players vertical jump and their explosiveness. It is going to isolate those 3 muscle groups and really work on developing strength.
It isn't enough to just do on court basketball training to develop your vertical, speed, quickness, etc. You need to also be supplementing your court time, with time in the weight room doing basketball specific exercises. This is when you will really see the growth athletically in your game as a player, or with your team if you are a coach. It takes time though to see the results, so stay patient and be willing to stay committed to the process.