The classic butterfly exercise is also possible when lying down.
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In the traditional butterfly exercise, you sit on the floor with your knees bent. With the soles of your feet together, you let your knees drop down toward the floor and bend forward from the hips to bring your nose closer to your toes. This stretch, which can be intensified by pushing gently on your knees, targets various muscle groups in your thighs and hips. It's particularly useful for stretching the adductors, the group of muscles responsible for bringing your thighs together toward the center of your body. Performing this exercise while lying on your side stretches and strengthens your hip area.
Changing It Up
In the side-lying version of this exercise, you lie on one side and bend your knees. Keeping your feet held together, you rotate the thigh of your top leg to move that knee toward the ceiling. Hold the position at the top of the movement before returning to the starting position. Throughout the exercise, strive to keep your hips stacked one on top of the other. When you first begin to do this exercise, your top hip will roll backward as you lift your knee. To prevent this unwanted movement, do the exercise by lying with your back against a wall or other solid surface. Start off doing one set of 10 repetitions with each leg. Gradually increase the number of repetitions and sets until you can do three sets of 15 repetitions with each leg.
What's in a Name?
The name of the traditional butterfly exercise comes from slight movement of your knees. When they move simultaneously, it resembles the wings of a butterfly. In the side-lying version of the exercise, however, only one leg can move at any given time. The floor restricts the movement of the other leg. Because the opening and closing of the top leg resembles the movement of a clam shell, this exercise is often referred to as the Clam or the Clamshell exercise.
Variations and Progressions
You can make this exercise more difficult by changing the angle of your hips. When your knees are close to your chest, the movement is easier. As you gain strength, decrease the bend in your hips until you are able to perform the exercise with your thighs in line with your torso. You can also make this exercise more difficult by strapping your thighs together with a resistance band or by wrapping a cuff weight around your top thigh, just above the knee.
The Clam exercise strengthens both your external rotators and your abductors. The external rotators lie deep beneath your gluteus maximus. These small muscles externally rotate the thigh in the hip joint. The gluteus medius and gluteus minimus, two of the important hip abductors, work to move your thigh away from the midline of your body. Strengthening these muscles helps you balance on one leg and move sideways more efficiently.