How many reps of the thoracic open book should a beginner do?

Six to eight slow reps per side, for one or two sets, works well before rotational lifts, throwing, or golf. Expect the arm to travel closer to the floor over sessions on its own, rather than forcing the reach on day one.

How do I make the thoracic open book easier or harder?

Easier: rest the top arm on a pillow partway through the rotation and stop there. Harder: hold each end range for three slow breaths while pressing the top knee firmly into the bottom one, or try the same rotation on all fours, where no floor guides the arm.

What is the thoracic open book for, and when should you pick a different drill?

It restores rotation in the mid-back while sparing the low back and shoulders, useful before rotational sports or any time the upper back feels locked. It is less useful if your real limitation sits in the shoulder or hip rather than the spine, since pinning the knees together specifically isolates thoracic rotation.

Beginner

Thoracic Open Book

Rotation lives in the thoracic spine, and this drill restores it beautifully while sparing the low back and shoulders. Lying on your side with knees fixed isolates the twist to the mid-back, so you get honest rotation without cheating from the hips. Use it before rotational lifts, throwing, or golf, or any time your upper back feels locked.

Equipment: Body Weight
Body part: Abs, Back
Type: Stretching
Browse by muscle: Abdominal External Oblique, Erector Spinae
Browse by movement: Mobility Drill

How to do it

1
Lie on one side with the knees stacked and bent to ninety degrees, arms extended together in front of the chest.
2
Press the top knee down into the bottom knee so the hips stay anchored throughout.
3
Reach the top arm up toward the ceiling and let it travel open toward the floor behind you.
4
Follow the moving hand with your eyes and let the chest rotate to open like a book.
5
Pause at your end range and take a breath into the stretch, then return the arm across.
6
Complete your reps on one side before rolling over to the other.

Tips

Keep the knees pinned together so all the rotation comes from the mid-back, not the hips.
Exhale as you open to let the chest settle a little further toward the floor.
Do not force the hand to touch down; range will improve rep to rep.

Variations

Common mistakes

The top knee lifts off the bottom knee as the arm opens, letting the hips join the rotation instead of isolating it to the mid-back.
Snapping the arm open quickly to reach the floor behind you trades a controlled thoracic rotation for a ballistic yank at the shoulder.
The head stays fixed forward instead of tracking the moving hand, which removes the visual cue that helps the rotation travel further.
Rushing straight from one side to the other without a breath at end range skips the moment where the chest actually settles into new range.

Frequently asked

How many reps of the thoracic open book should a beginner do?: Six to eight slow reps per side, for one or two sets, works well before rotational lifts, throwing, or golf. Expect the arm to travel closer to the floor over sessions on its own, rather than forcing the reach on day one.
How do I make the thoracic open book easier or harder?: Easier: rest the top arm on a pillow partway through the rotation and stop there. Harder: hold each end range for three slow breaths while pressing the top knee firmly into the bottom one, or try the same rotation on all fours, where no floor guides the arm.
What is the thoracic open book for, and when should you pick a different drill?: It restores rotation in the mid-back while sparing the low back and shoulders, useful before rotational sports or any time the upper back feels locked. It is less useful if your real limitation sits in the shoulder or hip rather than the spine, since pinning the knees together specifically isolates thoracic rotation.

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