Thoracic Open-Book Rotation

Move · Flexibility & Mobility · Movement, Typed Supps

Twists the mid-back, which is the part built to twist.

Stage by stage

Set-up (Lumbar spine locked out): Side-lying with hips and knees flexed and stacked, which limits lumbar rotation.
During (Thoracic rotation): The top arm opens across the body and the mid-back rotates, since the lower back cannot.
Immediately after (Rotation feels freer): Turning and reaching overhead usually feel easier straight away.
Weeks later (Overhead and rotational range): Thoracic range improves, which supports shoulder elevation and reduces compensatory lumbar rotation.

Muscles trained

Primary: upper back, obliques
Secondary: chest, shoulders, lower back

Intensity

2.3 METs (Stretching, mild).

Time to effect

Weeks: Rotation range improves within a few weeks; the immediate feeling of freedom is available in the first session.

Common myth

“Twisting is bad for your back.” In reality: Loaded, end-range lumbar twisting under fatigue is a genuine risk. Unloaded thoracic rotation is the opposite — it is the range the spine is designed for, and having it is what keeps the lumbar spine from taking the twist instead.