Beginner

Side-Lying Open-Book Stretch

The open-book is one of the best drills for restoring thoracic rotation, which most people lose to prolonged sitting. Lying on your side with the knees stacked locks the pelvis so the twist happens where you want it, in the mid-back. Follow the moving hand with your eyes and let each breath carry you a little further open.

Equipment
Body Weight
Body part
Back
Type
Stretching
Muscles worked
Target
Abdominal External Oblique, Erector Spinae
Secondary
Pectoralis Major Sternocostal

How to do it

  1. 1

    Lie on your side with the hips and knees bent to 90 degrees and both arms stretched out in front, palms together.

  2. 2

    Keep the knees stacked and pinned down for the whole stretch.

  3. 3

    Sweep the top arm up and over toward the floor behind you, opening the chest.

  4. 4

    Follow the moving hand with your eyes and let the head and upper back rotate.

  5. 5

    Hold the end position for a breath or two, return, and repeat several times before switching sides.

Tips

  • Keep the top knee pinned down on the bottom knee so the rotation stays in the mid-back.
  • Let the movement come from the ribcage, not from yanking with the arm.
  • Exhale as you open to sink a little deeper into the rotation.

Variations

Common mistakes

  • The top knee lifts and rolls back with the arm, so the pelvis turns too and the mid-back never has to rotate; a cushion under or between the knees gives them something to stay pinned to.
  • The arm swings up and over fast for rep after rep, so momentum carries the shoulder while the ribs stay shut.
  • The top hand stops in the air above the chest because the shoulder has run out of room; let the elbow bend and the hand travel only as far as the ribcage can take it.
  • The head stays facing forward while the chest turns, so the neck holds a twist of its own for the whole set; let the eyes lead the head around with the hand.
  • Hips and knees are bent well past ninety degrees so the thighs press into the ribs, which blocks the rotation before it starts; set both joints near a right angle.

Frequently asked

How many reps of the side-lying open-book stretch should a beginner do?
Eight to ten slow reps per side, one or two rounds, pausing for two breaths at the open position on the last few. Daily is sensible, and it works well before upper-body training or after a long stretch of sitting. Progress by holding the end position longer rather than by adding reps, since the point is range rather than volume. Do the stiffer side second and give it a couple of extra reps.
How do I make the side-lying open-book stretch easier or harder?
To make it easier, rest the stacked knees on a cushion or bolster so the hips are supported, keep the top arm bent with the hand near the ribs, and rotate only to where the shoulder is still off the floor. To make it harder, hold the open position for five slow breaths and breathe into the top ribs, reach the arm long so the back of the hand touches the floor, or hook the top leg over a bolster so the pelvis is locked and the rotation has to come from the ribcage.
What is the side-lying open-book stretch good for, and when is it not the answer?
It restores rotation in the mid-back, which is the first thing to go with long hours of sitting, and it opens the chest at the same time, so it makes a good start to an upper-body session or a daily desk antidote. The stacked knees are what make it specific. It is not the answer if your restriction is actually shoulder range rather than spinal rotation, and it is mobility rather than strength, so it will not build the rotational control a throwing or swinging sport needs.

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