The full read
This is a modest post in what it actually promises: a momentary repositioning trick, not a claim of fixing or permanently 'correcting' posture. The mechanism is consistent with shoulder functional anatomy: external rotation of the arm mechanically drives scapular retraction, which temporarily straightens the upper back — a simple enough biomechanical move that it doesn't need a dedicated study to be plausible. The physical therapist presenting it never claims this trick makes pain go away or replaces strengthening; it's framed as a one-off body cue, which matches what the posture literature actually recommends — moving and varying position rather than chasing one fixed 'perfect' posture (Slater et al., 2019, finds no single ideal posture that protects against pain). The only gap is no nuance on how long the effect lasts (probably seconds to minutes), but the video doesn't claim lasting change either. This is one of the few posts in the batch that doesn't overreach beyond what its own mechanism can support.
holds upthe post