Pool workouts aren't just for the injured and elderly. Sprinting in the pool is a creative way to cross-train. According to Kara Goucher's 2011 book "Kara Goucher's Running for Women," 30 minutes of running in the pool can burn 300 calories or more, just as much as running on land. The water takes stress off your joints by making your body buoyant while providing full-body resistance to enhance the challenge of your run.
Your pool sprinting workout can vary in duration, anywhere from 20 minutes to an hour depending on your fitness level and how long you typically train on land. Run in water that hits you around the shoulders. Swing your arms naturally but don't use your hands to help draw you forward. One difference about sprinting in water is that you'll keep your hands open instead of cupped, with your thumbs up. Run as you would on land but take longer strides and be sure to maintain an upright posture without hunching forward. Don't forget to warm up and cool down with five to 10 minutes of running in the pool at an easier, more moderate pace than your workout to get your blood going. Kind of like a jog in the water.
Make your pool sprinting workout enjoyable by bringing along some music. If you don't have a waterproof MP3 player, get a waterproof container for it at a fitness supply or electronics store or even just bring along a boom box and set it up a safe distance from the pool. Invite a friend or two for company and to participate in games like passing a ball as you run to keep things interesting and your heart rate elevated between sprints. If you have to go it alone, take a tip from Bob Wischnia's article "Head for the Pool" for Runner's World and alternating running with your fingers in and then out of the water.
Sprinting in the pool builds fitness, flexibility and overall body strength, according to Earl W. Fee in his book "The Complete Guide to Running: How to Be a Champion from 9 to 90." Pool sprinting isn't merely a substitute for running on land, it can boost your fitness level and actually improve your land speed due to the added resistance. The low-impact aspect of pool sprinting and the cool temperature make it a good option if you're pregnant, and, of course, it's a great alternative for bad weather.
Pool sprinting also has its drawbacks. You need access to a pool deep enough to provide an effective, challenging run, which could require a membership. You also need a special weighted belt that helps you maintain upright posture when sprinting through the water. Because of the cool temperature and pressure the water puts on your body, your heart rate won't get as high as when you run on land, and while the weightless, low-impact aspect of pool sprinting can be beneficial, impact is necessary for bone strength. Since women start to lose bone density around age 30 and it progresses from there, you should include other forms of exercise in your regimen that have at least some level of impact to counteract the decline in your bone density.