When the arm rises it never acts alone: total elevation is shared between the shoulder joint and the shoulder blade riding on the ribcage — scapulothoracic rhythm. Through the mid-range that share runs roughly 2:1, two degrees of arm motion per one of blade, inside a healthy corridor of about 1.7 to 2.5.

Roughly 30% of the golf swing happens above 90 degrees of arm elevation — the terminal range where the blade's contribution peaks, and where most golfers never feel it slip. Drift outside the corridor and the shrug takes over. That is the fault the Swing Band is built to catch, because band tension gets loudest exactly where a coach's voice reaches least.

Because a latex band pulls harder the further it stretches, every millimetre off-pattern changes what the student feels — a continuous error signal the nervous system cannot ignore, on every rep, with no verbal instruction. And the asymmetry is the signal: a shrug slackens the chest band and overloads the top, so the student feels where the error is, not just that there is one.

Motor-learning research consistently favors this kind of felt, external focus over verbal cueing about body parts — the constrained-action hypothesis. The Swing Band is an external-focus device by construction. Train the feeling; the swing follows.

A cast or a flip is a timing error the golfer can't feel in real time — by the moment they would notice, the ball is gone. The Swing Band changes that: the connection channel (Point 2, the chest-routed upper X-strap) rewards the hands staying with the turning chest and penalises them running ahead, and the wrist-hinge setting trains hinge and release timing against resistance that rises the further the pattern drifts.

So the student doesn't get told to stop flipping — they feel the flip as it starts, and the correct move as the quiet one. Train the feeling; the swing follows. The science is our job, not the student's.