Is sprinting speed genetic? Or can you get faster? ?

Genetics because the coaches scout and train the best athletes at a young age. Black people hit puberty and their potential quicker so they get picked first, plus they tend to have more fast muscle fibers than most people do. They say that other late bloomers miss out in this opportunity so that's why it's mostly a black people sport. Who knows if training can help even things out.

Is sprinting speed genetic?  Partially.

Can you get faster?  Not if you are at your maximum potential.

Genetics give you a potential maximum sprinting speed. But, other factors affect that. 

Let's say you have the genes that can make you faster than Usain Bolt. But, you eat a lot of junk food and are a couch potato. As a result, you are unable to come close to being able to run as fast as Bolt. You could reform, start training. Over time, your speed will increase. But, you may be limited: It may be your couch potato, junk food life style has reduced your maximum potential. 

If you live a life that a sprinter should live, can you become faster than your genetic potential? Maybe. It is easy to think of hypothetical situations, but they aren't realistic. There is also the possibility of cheating.

Let's say  you were born with some physical abnormality in your foot or leg that limits your sprinting. The cause is genetic. But, it can be corrected by surgery. 

You could cheat by taking performance enhancing drugs, or by other means.  But, if you do, I expect and hope you would be caught.