Muscle Focus- Abdominals. Objective- Strengthening the back extensors and mobilizing the spine. Reformer Setup- Start with one medium tension spring. Tension can be made heavier or lighter depending on the resistance desired. Place the Long Box onto the carriage with the short end of the box against the shoulder rests. The Footbar is up. Start Position- Lie prone on the box, with the hands on the Footbar in line with the wrists. Legs are straight and level with the box. Movement-Straighten arms to move the carriage then lift the head and thoracic spine into a Swan position. Keeping the arms straight, return the carriage while the body elongates and lifts. The body goes back down as the carriage goes back out. After final repetition, lower the body back down to the box, bend the elbows to bring the carriage home. Repeat as desired.