Specificity of Exercise:
If you want to get more controlled spins in tennis, practice hitting lots of tennis balls with topspin and backspin.
- Work on accuracy of your spins using different targets and depths.
- Use a ball machine or have someone consistently feed you tennis balls until you have the mechanics of the stroke mastered.
- Then add spin shots into your game.
When your goal is acquiring a certain skill, training with specificity of exercise will get you closer to your goal faster than doing different types of unrelated exercise. Repetition will give you the sensitivity of touch that you need.