I love this quote. This is from a famous distance runner named Steve Prefontaine from the United States (Oregon).
The meaning of this quote is to say that if you have the ability to do something but you don't give it your full effort you are wasting your "gift."
So, let's say that I am a very accomplished pianist. When I play the piano, if I just smash on the keys and don't really try to make beautiful music I am basically wasting (sacrificing) my gift.