Knee Stretches Arched Back (or Flat Back) on the Pilates Reformer is one of the trickier of the exercises in the series because it's easy to put the arch in your lower back, disconnect from your center and end up pressing from your chest and lower back. Often as the reps continue in this exercise more and more the lower back arches and it becomes about the hip flexors and riding the springs close. The more you work the extension up your spine and reach into the shoulder blocks from your seat the more this exercise becomes full body and helps you translate that work into more of your Pilates practice.
Try to keep your hips where they are and move your legs in and out.
Place two springs on the Reformer. If your springs are equally weighted then 2. If your springs have different weights then 2 heavy or one heavy and one medium. You want to be the one that closes the spring. Press your heels into the shoulder blocks and the ball of your foot into the carriage. If you are coming from the Round Back exercise, you simply lengthen your chest forward and make sure your center remains lifted. It's easy to think you stick your tailbone out or up but that will place this exercise into your lower back. Instead, reach your chest forward to create the length.
Once your chest is open, the arms are connected to your back and your heels are pressing into your shoulder blocks begin to press your carriage in and out 5-10x. Focus on pulling the carriage in and not pressing the carriage out. There is a rhythm your springs will have and you want to hear the emphasis on the in and not the out. Also, your hips should not be going up and down. Instead, try to keep your hips where they are and move your legs in and out.
Be sure to check out more of my online Pilates Reformer exercises. I want to help you continue your Pilates Reformer training!