From your transverse abs framing your midsection, your rectus abdominus running vertically in the middle, and your bikini hugging obliques, swimming effectively tightens each of your major ab muscles. Whether diving or swimming, each movement in the pool stretches and twists your abdominal wall. You’ll flex and tighten your abs just by jumping in and splashing around. You'll even tone your shoulders, glutes and thighs as you glide through the water.
The abs have many names -- "washboard abs" and “the six-pack" just to name two. The infamous "six-pack,'' the rectus abdominus, begins at the pubic bone, runs north and stops at the ribs. Your external obliques hang out next to your rectus abdominus, and your internal obliques run along your hipbones. The transverse abs -- the deep, dark bad boys -- are often left out while exercising. This muscle lies hidden beneath your other ab muscles and keeps your trunk stable.
Swimming and Its Strokes
Whether you hit the pool for fun or competition, there are four basic swim strokes: The freestyle, backstroke, butterfly and breaststroke. Of these four strokes, the freestyle, or front crawl, is the one that tightens your core the most. With its over-head arm movements and scissor-kick leg thrusts, this stroke strengthens the core by targeting the abs, glutes, back and shoulders. Those scissor kicks accomplish two things: Keeping you stable in the water and propelling you forward. Those kicks can also tighten your inner thighs.
Kick It Up With Water Aerobics
After swimming laps -- or in lieu of -- give your body a water-assisted cardiovascular pep talk. Water's natural buoyancy makes it an ideal alternative cardiovascular exercise for people with arthritis and chronic pain conditions, note authors Terry-Ann Spitzer Gibson and Werner W. K. Hoeger in their book "Water Aerobics for Fitness and Wellness." Core specific exercises, like rolls and ball levers, have stomach cinching power, suggests Rough-Fit master trainer Greg Moe in "Fitness" magazine. Moe suggests using a large beach ball for core toning otter rolls and ball levers.
Scheduling and Considerations
The key to a quality fitness routine is balance, according to MayoClinic.com. While swimming can tighten your stomach muscles and even those of your thighs, glutes and arms, aim to incorporate other types of exercise as well. For adults, the Mayoclinic.com recommends 75-minutes of vigorous activity a week, or 150-minutes of moderate aerobic activity. Chances are, if you have a swim routine you're meeting or exceeding those goals. However, pay attention to your body and rest between swims. Aches and pains are sign you're overdoing it.
Having studied at two top Midwestern universities, Catherine Field holds degrees in professional writing and patient safety. Writing since 2000, Field has worked with regional newspapers while publishing fiction online. She conducts medical communication research at a Midwestern medical institution and is slated to write a book based on her research findings.