Athletes and gym rats know the strain that an injury can have on their physical fitness. In order to avoid worsening the injury, doctors generally advise rest and limited mobility of the affected body part. However, an ankle in a cast or an arm in a sling can quickly deteriorate as muscles weaken, and the longer an active body is out of commission, the longer it takes to get back into shape afterward. Fortunately for people in this situation and others looking for a workout that doesn’t stress the body, deep-water running offers an excellent non-impact cardiovascular workout.

Six weeks before the 2010 Chicago Marathon, runner Jennifer Conroyd tore her calf muscle while training. Although she was unable to put any weight on her leg, let alone run, Conroyd was determined to somehow complete the marathon. Once her doctor cleared her to participate in water exercises, she realized how water’s natural buoyancy provided the perfect training environment for her injury.

Intrigued by the concept of deep-water running, Conroyd researched the concept and found an article about using this exercise for rehabbing and staying in running shape. She contacted the author, Kevin Beck, who promised he could get her to the marathon simply by training in the water.

For six weeks, she did nothing but train in the water. In the end, not only did she finish the marathon, she wasn’t far off of her best time. Two months later, she flew to Canada and started the certification process to become a deep-water running instructor and coach. Today, she offers deep-water running fitness classes with the Oak Brook Park District in Oak Brook, Illinois, and is working to develop a deep-water running instructor certification course in the United States.

“Americans have this stigma of water exercise classes,” Conroyd says. “We have a hard time believing water exercise is anything other than grandma’s water aerobics.” However, participants are able to enjoy all the cardiovascular and muscular benefits of land running, but without any of the impact. Since water offers significantly more resistance than air, participants are also able to strengthen their biceps and triceps and engage their core much more than they would while running on land, all while burning 30 percent more calories.

In a deep-water running course, students are suspended in the water by a flotation belt that is tethered to lane lines. Workouts are choreographed to music with interval sets to maximize the cardio benefits of the workout. The hydrostatic pressure (water pressure on the body), Conroyd explains, flushes out toxins, decreases swelling from injuries, and increases blood flow to the heart by 30 percent, resulting in improved aerobic fitness.

Deep-water running classes are currently an untapped source of fitness revenue in the United States, she says. Providing a unique group exercise opportunity, the overhead is minimal if an organization already features a pool with depths of six feet or greater. Conroyd’s classes require a certified instructor, floatation belts (approximately $30 each), tethers (if the facility has lane lines), 55 minutes of workout music, and a digital clock.

She says it is easy to attract participants to deep-water running programs as they provide a non-impact cardiovascular workout for everyone, including able-bodied and injured athletes, seniors, and those with foot, joint, or spine issues. Due to the specialized nature of deep-water running, agencies can charge premium rates for the classes and offer the program all year round as long as there’s access to an indoor pool, according to Conroyd.

Making the most of her newfound passion, Conroyd has established her own deep-water running company, Fluid Running, and is planning on launching the first U.S. deep-water running certification program in Oak Brook, Illinois, by the fall of 2013.

Jessica Cannadayis the Marketing and Promotions Manager for the Oak Brook Park District.