Purpose. A gradual and transient lengthening of the cardiac cycle (cardiac deceleration) is typically observed in the few seconds leading to self-paced precision actions and is reported as a feature of expertise. This study aimed to explore the time-frequency dynamics of this phenomenon.
Method. Sixteen young adults of varying expertise (novices to experts) performed 60 golf putts at a 4-m distant target on a flat surface while their performance and electrocardiogram were recorded. We measured the intervals between consecutive R waves to examine variations in cardiac cycle length. We then applied continuous Morse wavelet transform to extract time-frequency normalized power and phase, respectively indicating the relative magnitude and the position of cardiac cycle oscillations. We used cluster-based permutation statistics to evaluate the linear correlation between cardiac cycle metrics and variable error of performance outcome as a reverse index of task precision.
Results. Greater precision was associated with cardiac cycle lengthening (cardiac deceleration) not only in the final 5 s before movement but also around 10 s before movement and even with cardiac cycle shortening (cardiac acceleration) around 5 and 15 s before movement. Time-frequency analyses revealed that greater precision was associated with (a) lower normalized power for frequency content above 0.2 Hz and below 0.08 Hz, (b) greater cross-trial consistency of both normalized power and phase, and (c) a specific oscillatory phase consistent with a 0.15-Hz cardiac cycle lengthening beginning around 2.5 s before movement.
Conclusion. This study provides evidence that the cardiac deceleration expertise effect may be part of a broader peripheral-nervous-system phenomenon consisting of 0.08-0.2 Hz oscillations, positioned in time so that the heart rate decelerates just before and during movement.