There are a number of guiding principles that Joseph Pilates identified as being important in creating a strong, lean, balanced body. One of those principles is that of your breath--not as in your "morning breath" but rather in the manner that you breathe and incorporate your core into your breathing. One of the first Pilates courses I attended about 8 years ago, Pilates for Physical Therapists, spent nearly 30 minutes on the exercise of breathing! Most of my clients would become rightfully impatient if all we did in class was focus on our breathing muscles--however there is value in recognizing the importance of the breathing musculature and its relationship to our core training. We tend to lead our lives at a rapid pace and take short, shallow breaths--not fully accessing the power of our lungs and expanding the breath into our ribcage and intercostals. I remember waking up the day after that first class feeling like I had taken a small beating to the sides of my body...the intercostal muscles that line the ribcage were mobilized effectively through inhaling or breathing "into the sides of the body" in Pilates speak. The process of exhalation relies significantly on the deepest layer of the abdominal muscles--the transverse abdominis which encircles the torso. This muscle acts like a girdle to flatten the abdominal wall and contracts upon exhalation. We can strengthen this muscle further by drawing the navel in and up upon exhalation. In simple terms, grandma was right, to improve posture we should hold in our stomachs and in the process it actually strengthens the muscle. I can recall working with patients in the hospital whose core musculature was so weak that they could barely summon a cough which requires a deep inspiration and strong expiratory effort from the obliques and transverse abdominis. Breathing is truly an exercise and one in which muscles can be strengthened with effort and awareness. Whether you are in the car, standing in line at the store, or watching your favorite tv show take time to focus on your breathing. "Inhale into the sides of your body and exhale through a relaxed jaw and mouth(like a sigh) drawing the abdominals in and up." As in most exercises, strive for a "relaxed effort" with your breathing which will lead to a relaxed effort with your sport or daily living task.