Arm Swing Negative Resonance

Complete Practice

Stand and let your arms hang. Initiate a small pendulum swing in one arm, shoulder-driven, at its natural rate. Now invert the usual axiom: instead of pushing the swing larger, try to suppress it by introducing a counter-effort at exactly the wrong moment in the cycle — push downward when the arm is rising. The precise quarter-cycle within which a tiny counter-pulse is most effective at killing the swing. That quarter is the antinode of the velocity profile, and locating it teaches you where the swing actually lives. Challenge: The practitioner may unconsciously time the counter-pulse to phases where the arm is already slowing, confounding cause and effect.