Degrees of Freedom and Conserved Quantities in Golfer-Environment Systems: An Ecological Analysis of Visual Kinesthesis and Screw Dynamics in the Golf Swing

We propose a new ecological theory of golf swing coordination based on the interaction between degrees of freedom and conserved quantities in golfer–environment systems. Using screw theory and motion capture data, we analyze pitch invariance along the Instantaneous Screw Axis (ISA) as a conserved action structure. Crucially, we introduce visual kinesthesis-the perception of displacement through optic flow-as a key perceptual anchor during impact, when proprioceptive cues are unreliable. Our findings show that skilled golfers exploit stable ISA trajectories and tightly coupled pitch–force dynamics to produce perceptually invariant motion. Visual kinesthesis, not feedback correction, guides this coordination, while haptic kines- thesis governs internal calibration during the swing. These results suggest that pitch and ISA geometry function as conserved quantities, providing an ecological foundation for understanding skill as emergent sensorimotor alignment.