Pilates taught that the Powerhouse is a combination of 3 strong muscular areas: the glutes, abdominals and lower spine muscles. He taught that we must engage the Powerhouse consistently through all exercises. Pilates would famously cue "Engage the Powerhouse!" when teaching his students. Glutes, abdominals and lower spine muscles do a wonderful job stabilizing the pelvis and ribcage but…

There is a 4th area of the body we need to include in our Powerhouse located on the back of our upper arms where our arms meet the side of our shoulder blades. Each shoulder blade has a divot where the head of the arm bone fits. The muscles here are called The Rotator Cuffs. Every Pilates exercise requires the ability to maintain stability where the upper arm bone attaches to the sides of the shoulder blades using the rotator cuff muscles.

Mindful effort is used to maintain arm/shoulder alignment. In Pilates we refer to this effort as the principles of Precision and Control. The pace of the exercises are determined by the effort needed to stabilize the alignment of the skeleton.

The beauty of this work is from all the effort comes an effortlessly graceful posture. Exercising with proper arm/shoulder alignment and stable shoulder joints trains a youthful, athletic posture even if you aren't young or athletic (you can look and feel like you are!).

I think we need to include the muscles of the rotator cuff when we "Engage the Powerhouse". You can try it now. Use your imagination to slowly pull your upper arm bones backward a little. At the same time think about squeezing an orange in each arm pit. The sensation will be a firmness on the side of your shoulder blades and the back of your upper arms. The intensity should be about a 5 out of 10. Try to maintain the firm feeling while making arm circles (and every other Pilates exercise you practice in the future).

Crunches and Sit Ups are great, but not everybody is well suited for these targeted core exercises. If spine, shoulder or hip issues are present in your body, traditional abdominal exercises don't make sense. If there are energy issues or deconditioned abdominal muscles, a sit up or crunch isn't the right exercise.

Pilates to the rescue! The Reformer and Trapeze Table (Cadillac) are both designed to work the abdominals simply by pressing your body into the machine and keeping it stable while moving either the arms, legs, or both. In Pilates we call this technique Stability.

On the Mat, Reformer Carriage, Trapeze Table, and Chair top we use touchpoint feedback to stabilize the body and learn what stability feels like.

It is an elegant way to work. It looks and feels graceful. From a novice perspective, the stillness of a skilled Pilates practitioner is well hidden. Holding the skeleton still with deep, core muscles kind of looks like "not moving". But the work needed to perform stability well will make every muscle in your body quiver. We call it "earthquakes" — the feeling that your abdominals are vibrating while stabilizing during a Pilates exercise; it means you're doing it right.

For example, to set up Supine Arms on the Reformer, every bone in your torso is placed on the Reformer Carriage with care. Breathing is controlled to maintain perfect skeletal alignment. The Reformer provides the structure for your skeleton, but your abdominals are in charge of keeping your spine and shoulders absolutely still on the Carriage as your arms move in big sweeping repetitions attached to the ropes and pullies. During repetitions, your focus circulates around every touchpoint between your body and The Reformer, maintaining consistent pressure everywhere your body touches down. Earthquake City.

Every Pilates exercise uses Stability to create deeply engaged core work. When practicing Roll Up on the Mat, stabilize your heels, calves and glutes into the mat as you roll through your entire spine head to tailbone. During Rollover on the Mat, your head, shoulders and arms remain glued to the mat, stabilized, while the legs and entire spine move with the strength of the abdominals.

Understanding which points of the body are supposed to move, and which parts are meant to stabilize during each Pilates exercise will simplify your progress and speed the results of your work in the Pilates studio.