Lie down on a mat and lift up your legs so your feet are perpendicular to your hips. Keep your feet apart at shoulder width and your arms relaxed alongside your body. Keep your head upright and do not bend it back.
From the starting position, lift your pelvis slightly up from the mat by contracting your abdominal muscles, having your legs pointing upward. As you are lifting up your pelvis, simultaneously rotate your hips laterally in the upper position. Then lower your pelvis slowly back onto the mat in the same way and when you go up again, rotate your pelvis in the opposite direction, alternating direction. Inhale in the starting position, hold your breath (for a short while) while fixing the trunk, and subsequently exhale in the starting position and repeat the exercise inhaling again. Do the required number of repetitions, alternating the rotation to both sides.
Pay attention to your body posture, fix your trunk, keep your pelvis in a neutral position and avoid excessive bending at waist.
Keep your legs in the same position throughout the entire movement.
Eliminate engaging your chest and shoulder muscles when overcoming the resistance. Seek to keep your shoulders constantly pressed against the mat.
Keep your head in a neutral position leaning against the mat.
Take account of your breathing while doing the exercise and do not move in a dynamic way.
The exercise, when executed incorrectly, may lead to lower back injuries. For that reason pay attention to doing the exercise correctly.