This improvisations are important part of my warmup and daily practice, i use to improvise over a track like this from various styles after some routine exercises, the idea is to improvise long enough and try not to be repetitive, which is sometimes hard, as you have to come up with some new (not used) melody or phrase "on the fly" while playing...
Also, another good practice is to play 2 times (or more) over the same backing track and try to do 2 completely different approach each time, so i may go back to this backing track later, but will try to play something completely different...
Anyway, hope you like it!
Rafael.