Muscle Focus- Shoulders and Back Extensors. Objective- Strengthening the back extensors shoulders. Reformer Setup- Start with one medium tension spring. Tension can be made heavier or lighter depending on the resistance desired. The Footbar is up. Start Position- Kneel on the carriage with feet against the shoulder blocks. The toes should be tucked under with the soles of the feet against the shoulder blocks. Hands are on the Footbar shoulder-distance apart. The hips are pushed forward into a posterior tilt so that the spine is in extension. Movement-Keeping the arms straight, press the carriage back, maintaining the position of the spine. As the carriage returns home, the chest should lift slightly to elongate the spine. Repeat as desired.