Unlike so many other guys strutting around the gym, Michael Phelps isn’t spending hours each day targeting his core for that defined six pack.

Yet despite this lack of attention, almost all competitive swimmers easily have carved abs.

So How Is It Done?

The truth is, swimming burns more calories than almost any other cardio that you can do. Michael Phelps eats an average of 4,000 calories. For breakfast. Despite this huge amount of calories (sometimes hitting 12,000 a day) his time in the pool leaves him a lean, mean swimming machine.

These burned calories result in less fat that on your midsection, revealing more toned abs underneath.

But swimming can also build up those abdominal muscles, and we’ve found the most effective underwater workouts for your core.

Freestyle

More than any other stroke, the freestyle keeps your body long, creating lean muscles. as you keep your legs and head close to the surface, both your lower back and abs will tauten.

The alternating strokes will also cause your body to rotate as if on a spit. As you pull each arm through the water you tighten the opposite side of your abdominals helping you build up your obliques and get an all over workout.

Butterfly

Easily the most strenuous stroke, the butterfly relies heavily on strong abdominals and lower back muscles to propel you forward and through the water.

Each time you kick with your legs together, the motion starts almost at your belly button, letting your core be the powerhouse for this stroke.

But unlike so many ab workouts that leave your lower back strained, the butterfly kick’s rebound relies on the back muscles to make sure you can go through the full motion of the kick. Not to mention that every time you breathe you’re pulling your upper body out of the water with your back muscles.

So rather than sticking to boring crunches, expand your repertoire for ab workouts to ones that you can do in the water.