The really good news though is that the strength training you do in the pool can pay off in faster race times come springtime. The key is to make sure that your workouts in the pool feel as hard as your workouts on land. Here's some even better news. In a 6-week study of runners who ran only in deep water and not a single step on dry land, deep water running was actually proven to preserve racing ability. The downside is that it can get boring.
Interval work helps to break up the monotony.
Fitness Swimming Unlike most cardiovascular workouts, swimming works all of your major muscle groups, but is particularly good for building upper body strength. It also increases your body's capacity to attract more oxygen from your lungs, which can improve your running and cycling. Even if it's not your best stroke, the freestyle stroke is most efficient at raising your heart rate. That's because your heart doesn't have to work quite as hard in cool water to get the same cardiovascular benefit. In addition to straight swimming, you may wish to incorporate some interval work with the kickboard or pull buoy.