New swimmers tend to swim with their belly buttons towards the bottom of the pool. This stems from the misconception that the body must remain rigid and straight to float and cut through the water. But swimming flat like this is detrimental to your overall performance. Ideally, the body should rotate side to side with every stroke for a more natural movement.
Why Body Rotation Is Important
Fluidity in body rotation, known as rolling, is an essential component in most stroke techniques for four reasons:
In a flat position, your shoulders must rotate awkwardly for your arms to clear the water. Unless you roll as you complete your strokes, the rotator cuff gets overworked quickly.
Flat swimming relies most heavily on the shoulders and arms for propulsion power. During a body roll, though, you incorporate larger muscle groups into the stroke like the lats, pecs and core.
Rolling the body allows you to reach further ahead to catch the water. This increases the amount of pull time in each stroke, helping you swim faster and more efficiently.
Flat swimming puts the face directly underwater, forcing you to turn your head at extreme angles to catch a breath. This exaggerated movement makes it more difficult to breathe consistently and effortlessly, adding to the sensation of breathlessness after only a few laps in the pool.