Muscles and fitness: Swimming: How training shapes your figure

Light rain patters on the water's surface as the first swimmers make their laps. The air is a cool ten degrees, and the water is just ten degrees warmer. But Katharina von Schön-Angerer (41) doesn't care: Since her favorite outdoor pool in Hamburg-Eppendorf reopened, she's been swimming laps in the 50-meter pool early in the morning. 60 minutes, about 2,000 meters freestyle, three times a week.

Shortly after seven o'clock, she jumps into the pool, puts on her headphones, switches on her waterproof MP3 player , and swims against the sounds of Max Herre, swimming the day ahead and shedding the extra pounds. She started swimming a good year ago, "but back then I only did breaststroke; I couldn't even swim properly." A few hours of lessons with a swimming coach got her back on track. Her crawl technique improved, and ingrained mistakes were fewer.

200 meters of freestyle became 400 meters, then 800, finally 1400, and finally 2000 meters of freestyle swimming in one go. "I needed some kind of endurance sport; yoga was too boring for me. Running wasn't possible because of my bad knees, and cycling is too time-consuming and too painful for my butt," she says with a laugh. The fact that she's now lost eight kilograms of unwanted fat in her pelvis, her posture feels better, and her muscle tone stronger, "is just fantastic," as the interior designer likes to say. It's no secret that swimming is one of the healthiest sports: The buoyancy of the water means we barely feel our weight, so the strain on our joints is minimal. The movements are slower, but the water resistance makes them more powerful than on dry land.

Swimming challenges and strengthens around 170 muscles that are involved in the various swimming strokes. The cardiovascular system is also improved, but in a gentler way: the horizontal position and the water pressure make each heartbeat more effective and the amount of blood pumped is greater than outside of the water. Scientific studies prove the economization of the heart: while the heart needs 137 beats per minute in water for a certain intensity of exercise, twelve more beats are needed for the same effort when running. This also shows that you can't simply transfer heart rate targets for running training or similar to swimming training. When it comes to calorie consumption , swimming is no slouch: one hour of breaststroke burns a similar number of calories as one hour of cycling (around 530 kcal), according to a study by the Institute for Prevention and Aftercare (IPN) in Cologne.

And anyone who spends even an hour swimming crawl in the pool burns up to 900 calories – almost 35 percent of which comes from fat deposits. The high energy expenditure also results from the generally quite cool water temperatures. Only at a water temperature of 26 degrees Celsius is the heat exchange between body and water in balance. If the temperature is significantly lower, the body uses additional energy to avoid cooling down. In doing so, it burns fat without you even noticing. So, once you have a basic technique, swimming can be used as a targeted body-tuning tool. "For beginners, it's a good idea to supplement swimming training with some strengthening exercises on land in order to build swimming-specific muscles more quickly," advises former German Swimming Federation (DSV) national coach Dirk Lange (50). "A Thera-Band is ideal for this because you can use it anywhere and adjust the load according to your individual requirements."

Swimming isn't just a fat burner, it's also a mental booster: The steady movement in the water promotes the production of the hormones endorphin and serotonin, which increase our feelings of happiness and also reduce stress and build confidence. Anyone who has experienced the feeling of flow in the water thanks to the right technique can experience the same experience as world champion Paul Biedermann: "For me, the sport has something meditative about it. When you're tired of listening to someone else, you jump into the water and find peace and quiet. The movement is incredibly powerful, aesthetically pleasing—and yet you feel weightless." At first glance, many of his fellow countrymen seem to share Biedermann's experience: After cycling and gymnastics, swimming is the third most popular sport among Germans over the age of 18. According to a study by the Society for Communication Research, one in ten people regularly jumps into the water. However, these people probably often equate splashing around with swimming.

Many who say swimming is one of their favorite activities probably feel more like our colleague Julia Nadolny (24): She'd like to do more, but can't. "I just don't get that easy, meditative flow experience that you often get when running." Swimming coach and former Olympic swimmer Glen Christiansen (55) confirms: "Poor swimming technique combined with incorrect breathing technique often leads to beginners quickly becoming out of breath, barely making any progress, and then giving up in frustration. But it only takes a few hours with a good coach who gives the right tips – and the fire for swimming is ignited." So FIT FOR FUN brought the two together, and after six years of not going to the pool, our colleague Julia joined Coach Christiansen for a few hours to discover the joy of the flow experience. You can read whether it worked in the blue box below!

More power in the pool: 8 tools for more fun and style in the pool can be found in our picture gallery !

FIT editor and regular swimmer Julia Nadolny noted: A good trainer, the right tips – and after a short time, it works. Relaxing and swimming a few laps freestyle – that's always been my dream! For me, swimming well at the front crawl is the coolest way to make a splash at the pool: it looks casual, and you feel like you belong. My problem so far: after just half a lap, I start gasping for breath, and I have to quickly row to the edge of the pool to cough up what feels like two liters of water from my lungs. That's about to change – with the help of my new coach, I'm now working on my technique and fitness. After just two laps under Glen's critical eye, he's identified the reasons for my previously unsuccessful attempts at the front crawl.

Besides breathing (before I can breathe in properly, I have to exhale the used air), my legs are a weak point. My leg kicks are far too hectic and I quickly waste all my energy. Also important: stomach tucked in, bottom up. This way, my legs don't sag, and I experience less resistance in the water. After a few training sessions with a pull buoy, hand paddles, exercises for arm and leg kicks, and breathing techniques, I can actually glide a few laps through the water fairly elegantly – without having to pant as I head for the edge of the pool. It's incredible how quickly you can get into the flow, even when doing the crawl, with the right technique and a little training.