The buoyancy of water suddenly frees us from the constant drag-down effects of gravity and can feel like a welcome relief. For those of us who feel less mobile or have had an injury, this can offer very real benefits. But while movement may become easier, that doesn't mean that using water is exercise-lite; water reduces our body's weight by as much as 90 percent, but it is also 800 times denser than air. This means there's more resistance—although with less strain—so it's the perfect environment for strengthening and toning.
According to Mary E. Sanders, PhD, associate professor of exercise science at the University of Nevada in Reno and director of WaterFit (www.waterfit.com), water provides about 15 times more resistance than doing the same moves on land.
Swimming can be particularly useful for people with arthritis and other painful inflammatory joint conditions. As one review reported regarding maintaining function for those with arthritic conditions: "When people are unable to exercise on land, or find land-based exercise difficult, aquatic programs provide an enabling alternative strategy."1
When we are submerged, water pressure has a cushioning effect on the joints, limbs and tissues, whereas more energy is needed to move the body, so more calories are used. All of this together with the calming effect, via the parasympathetic nervous system, of being submerged in water offers the perfect combination of a stress-relieving, yet effective, workout.
The cushioning effect of water also means that people with injuries can continue training in ways that would exacerbate damage and inflammation if performed on land. Points of weakness can be strengthened, as water allows traction and an increased range of motion without further strain—for example, in the knees, hips and lower back, common areas of sports- and age-related injury. The hydrostatic pressure of water even has a massaging effect, acting as an auxiliary heart pump, bringing fresh blood flow to areas needing rejuvenation.
Warming up in a pool is easy but dependent on the temperature of the water.
The following warm-up moves through the whole body and gets you used to being in the water.
Jog at the shallow end for 2 minutes in water at about chest height—where you get drag and resistance against most of your body, but can still use your arms and shoulders to facilitate the movement.
Allow your shoulders to move fully, and rotate them as you go to loosen any tightness there.
Still at this water depth, bring your feet together and jump from side to side to open up the sides of the body and create heat within the muscles. You can hold onto the side with both hands if you need to, but try to always drop most of your weight into your feet rather than arms. Continue this for 1-2 minutes.
Holding on to the side of the pool with arms outstretched, and keeping your legs and feet under the water, kick as if you want to propel yourself forward. Keep the knees straight to make the motion come from the ankles, and allow your body to sway into the motion to loosen up the sides of your body too.