Sports can be a great way to get in shape or stay that way. Having a specific goal can be a great motivator. Physically, you need strength and endurance. Your training will vary with your sport. You would not train the same way for pole vaulting as for swimming. You might, however, cross train. Cross training simply means that you include a variety of fitness activities in your program. Research shows that cross training builds stronger bones.
Remember to listen to your body. If you frequently feel exhausted or you are in pain, you may be overdoing it. Injuries can be the result. And be sure that you use your body and your equipment safely. What you eat and drink is also important. Water is the most important nutrient for active people. Drink it before, during and after workouts.