Peak Pilates Master Trainer Colleen Glenn demonstrates the correct setup for the Short Box Series, a group of exercises designed to work the various planes of the Powerhouse. The first exercise in this series is Round Back. This exercise is intended to strengthen the Powerhouse and articulate the spine. Round also initiates a curl from the pelvis while pulling the sacrum down. Flat Back is the next exercise in the series and is designed to teach proper separation of the hip and pelvis while adding axial elongation. Side-to-Side is the third exercise in the series and teaches how to reach the ribs off the pelvis as opposed to bending sideways. Side-to Side also lengthens the torso. Twist is the next exercises in the Short Box Series and lengthens out both sides of the body while lubricating the spine by twisting. The next exercise, Tree (Front Only), is designed to stretch the hamstrings, lower back and entire spine while better aligning those with asymmetrical challenges. The final exercise in the series, Side Sit-Ups, strengthens and stretches the sides of the Powerhouse while lengthening both sides of the body equally.