When you do find your groove, your consciousness has changed. This is shifting consciousness, and shifting conscious levels is what hypnosis is about. Hypnosis can teach you about concentration levels. In contexts other than sport, hypnosis can be more useful because the situations are more limited and have a better chance of control. But in sports, with all the distractions, hypnosis is best thought of as a warm-up exercise.
Hypnosis is the manipulation of concentration levels.
And, in sports, most of the benefit can be achieved by slipping down a couple of concentration levels. Some form of this shifting of concentration you've already experienced. If you've ever spaced out while driving or glazed over during a boring lecture, you know what it's like to slip down a couple of concentration levels. The trick is to be able to do it at will. Props can help you shift contentration levels, and sports are full of props.