How many repetitions or how long per side?

Eight to twelve slow sweeps per side, or about 45 to 60 seconds, is a practical dose. Adding a short pause at the point where the chest stops opening is more valuable than adding repetitions.

Does my hand need to touch the floor?

No. Many people never get the back of the hand to the ground, and chasing it usually means the pelvis has rolled or the shoulder has taken over. Work to where the chest stops opening instead.

Should I use it before or after training?

Before, in most cases. It is an active drill, so it prepares the shoulders and mid back for pressing and overhead work without leaving anything feeling loose.

How does it compare to the Lying T-Spine Rotation Stretch?

Both open the chest and rotate the upper back, but this one is side-lying with the knees stacked, while the Lying T-Spine Rotation Stretch is done on the back with one knee crossed over to pin the pelvis. Pick whichever gives you the cleaner anchor.

Can I do it every day?

Yes. It is low intensity and short, and desk-based trainees usually see the most benefit from doing a set most days rather than a long session once a week.

Open Book Stretch

What Is the Open Book Stretch?

Open Book Stretch is a mobility exercise that primarily targets the chest, opening the pectorals and the front of the shoulder, and it also works the obliques, the lats and the muscles along the upper back. It is a beginner-level movement performed side-lying on the floor with no equipment, and it is logged for time.

The setup is what makes it effective. Lying on one side with the hips and knees bent to roughly 90 degrees and stacked, the pelvis is trapped against the floor before the movement starts. Both arms begin extended in front at shoulder height with the palms together, and the top arm then sweeps up and over toward the opposite side while the chest turns toward the ceiling. Because the legs cannot follow, everything the arm gains has to come from the ribcage and the shoulder girdle.

That combination of a chest opening and an upper back rotation is why the drill is so widely used in warm-ups for pressing, overhead and pulling work. Anyone who spends the day with the arms in front of the body, at a keyboard or a steering wheel, tends to lose exactly this range first, and the position restores it without needing a wall, a doorway or a partner. It also pairs naturally with the Doorway Chest Stretch when the chest is the priority rather than the mid back.

Variations mainly change what the top hand does. Sliding the hand along the floor keeps the shoulder low and emphasizes the chest, while reaching it up in an arc through the air draws more rotation from the mid back. Placing the top foot on a foam roller or a folded towel raises the knee slightly and gives the pelvis a firmer block. A supine alternative that anchors the pelvis with a crossed knee instead of stacked legs is the Lying T-Spine Rotation Stretch.

The most useful thing to focus on is the eyes and the ribs, not the hand. Letting the gaze follow the moving hand pulls the head and neck into the rotation naturally, and thinking about turning the ribcage rather than reaching the arm keeps the shoulder from doing all the work. Slow sweeps with a short pause where the chest stops opening give a far better result than fast repetitions.

Muscles Worked

MuscleActivation

Pectoralis Major: Primary
External Oblique: High
Latissimus Dorsi: High
Deltoid: Medium
Erector Spinae: Medium
Rhomboid Major: Medium
Rectus Abdominis: Low
Serratus Anterior: Low
Upper Trapezius: Low
Thoracolumbar Fascia: Minimal

Instructions

Lie on your side on a mat with your hips and knees bent to about 90 degrees and stacked on top of each other.
Extend both arms straight in front of you at shoulder height with your palms together.
Rest your head on a folded towel or a low pillow so your neck stays in line with your spine.
Press the top knee down into the floor to keep the pelvis from rolling.
Exhale and sweep the top arm up and over toward the opposite side, turning your chest toward the ceiling.
Let your eyes follow the moving hand so the head rotates with the upper back.
Stop when the top knee starts to lift, then hold for two or three slow breaths.
Bring the hand back to meet the other palm under control.
Repeat for the prescribed time, then roll over and work the other side.

Common Mistakes

Letting the top knee lift
When the knee comes off the floor the pelvis rotates with the trunk and the stretch stops reaching the chest and mid back.
Reaching with the shoulder
Driving the hand back while shrugging the shoulder toward the ear loads the joint instead of opening the chest.
No head support
Lying with the head unsupported leaves the neck bent sideways for the whole set, which is usually what people feel afterward.
Sweeping too fast
Rushing the arm through its arc skips the end range where the actual change happens.
Straightening the legs
Letting the hips open past 90 degrees loosens the anchor and lets the whole body roll backward instead of rotating.
Looking straight ahead
Keeping the gaze fixed forward leaves the neck out of the rotation and cuts the range short.

Injuries

Open Book Stretch is a low risk exercise when performed with proper technique. The floor supports the trunk, there is no load, and the stacked knees limit how far the movement can go, so problems are usually a result of speed or a collapsed setup.

The front of the shoulder and the neck are the two places to watch. Shoulder discomfort comes from throwing the arm back and letting it hang at end range with the shoulder blade shrugged toward the ear, which stresses the joint capsule rather than the chest. Neck discomfort comes from lying without any head support, so the head drops toward the floor and stays laterally flexed for the whole set. A folded towel under the head and a slow, controlled sweep resolve both. Anyone with a recent shoulder dislocation, an unstable shoulder or an acute neck issue should keep the arm path short and get clearance before working at end range.

To regress the stretch, keep the top elbow bent and slide it along the floor instead of reaching with a straight arm, or reduce how far the hand travels. To progress it, hold the end position for longer, add a light exhale at the top of each sweep, or move on to standing chest work such as the Doorway Chest Stretch once the range is comfortable.

Stop if you feel pinching at the front of the shoulder, sharp pain in the neck, or any tingling running down the arm. A broad stretch across the chest and the front of the shoulder with a sense of the mid back opening is the intended sensation.

Overview

Primary Focus: Chest
Equipment: Body weight
Modality: Stretching
Difficulty: Beginner

Alternative Exercises

Frequently Asked Questions

Q: How many repetitions or how long per side?: Eight to twelve slow sweeps per side, or about 45 to 60 seconds, is a practical dose. Adding a short pause at the point where the chest stops opening is more valuable than adding repetitions.
Q: Does my hand need to touch the floor?: No. Many people never get the back of the hand to the ground, and chasing it usually means the pelvis has rolled or the shoulder has taken over. Work to where the chest stops opening instead.
Q: Should I use it before or after training?: Before, in most cases. It is an active drill, so it prepares the shoulders and mid back for pressing and overhead work without leaving anything feeling loose.
Q: How does it compare to the Lying T-Spine Rotation Stretch?: Both open the chest and rotate the upper back, but this one is side-lying with the knees stacked, while the Lying T-Spine Rotation Stretch is done on the back with one knee crossed over to pin the pelvis. Pick whichever gives you the cleaner anchor.
Q: Can I do it every day?: Yes. It is low intensity and short, and desk-based trainees usually see the most benefit from doing a set most days rather than a long session once a week.