If your pool time consists of lounging in a chair with your favorite book and occasionally dipping your toes in to refresh, you're missing out on a serious workout opportunity. Water offers 12 times the resistance of air, so every action you take is that much harder and more effective. This is true for any exercise, including those that tackle your stomach region.
You might think the best way to tone your stomach in the water is some aqua variation of a crunch or hanging leg raise. While these moves do work the muscles of your abs, they don't directly work off any fat that hides definition in the stomach area.
Treading water, however, burns 400 to 500 calories per hour, and when you burn calories to create an energy deficit, it helps get rid of extra fat on your body to reveal a svelte tummy. It also requires incredible activation of your abdominals and the rest of your core to keep you upright and breathing. Your abs provide the powerhouse from which your arms and legs work.
Treading Water 101
Treading water involves moving your arms and legs to keep yourself upright in deep water. For a quality workout, get into water where you can't easily touch the bottom. If you aren't comfortable swimming, make sure the pool edge or a life raft is nearby to support you when you fatigue.
Practice two skills required for treading water:
Scull Your Arms: Practice this in shallow water in which you can stand until you're comfortable taking it to the deep end. You'll move your arms around right under the surface of the water with stiff wrists and sweeping hands. Bring your hands toward each other and then away from one another in a rapid fashion.
Flutter Kick: While in water deep enough that your feet can't touch, hang your legs toward the bottom. Scissor kick your feet front to back rapidly to help keep you afloat. Point your toes and keep your legs straight as you kick. Hold onto the pool edge or a floating device to keep your upper body afloat as you practice.
Either of these skills can be practiced while straddling a pool noodle until you feel comfortable and strong enough to do them on their own.
Make Treading Water a Workout
Treading water for a straight 20, 30 or 60 minutes is pretty intense and draining. Instead, make treading water an interval workout by going all out for 30 to 60 seconds and then floating on your back, holding onto the pool wall or sitting on a noodle for an equal amount of time. Do 10 to 15 sets of these on/off intervals to get a complete workout.
You'll also burn more fat working with intervals than you will with steady-state activity, notes a paper published in a 2011 issue of the Journal of Obesity. Burning more fat means you'll reveal the tone in your abs more quickly.
Warm up before going into a tough water treading workout. Swim a few laps at a gentle pace. Alternatively, walk or march in the shallow end for 3 to 5 minutes.
Finish with Water-Specific Ab Exercises
Use a kickboard to maximize the resistance provided by the water. These moves use your abs to do what they're supposed to -- stabilize you!
Push and Pull
You'll use a lot of abdominal stability to keep from toppling over as you push the board.
Stand feet hip-distance apart in water that comes up to your shoulders. Hold the kickboard flat against your chest.
Push the kickboard forward until your arms are straight. Pause and pull the board back.
Continue to push and pull for 30 seconds. Move as rapidly as you can to get the most out of the exercise.
This move requires a lot more control than you might think. Keep your chin up so you don't have to hold your breath as you work.
Float on your belly in the water -- body extended long in the pool. Hold a kickboard between your hands and push it straight down toward the bottom of the pool.
Keep holding the board as you extend your arms up by your ears. It will rise just up to the surface of the water.
Push the board back down to the starting position. Perform 10 total repetitions.