Temporal patterns of prefrontal hemodynamics during Tai Chi, Baduanjin, and Liuzijue: a wearable fNIRS study protocol

Traditional mind-body practices integrate movement, breathing, and attention, but the temporal characteristics of prefrontal hemodynamics during ongoing practice remain unclear. This study protocol aims to compare process-level patterns of prefrontal oxygenation during 24-form Tai Chi, Baduanjin, and Liuzijue. Approximately 45 healthy college students aged 18-22 years are expected to be enrolled. Recruitment will continue, if necessary, until 36 participants have provided complete and analyzable data for all three conditions. In a within-participant Latin-square design, each participant will complete the three practices on separate days. Each session will include a 120-s quiet-standing baseline followed by one 6-min practice trial with standardized audio cues. Wearable functional near-infrared spectroscopy will continuously record HbO and HbR over the bilateral dorsolateral and frontopolar prefrontal cortex, alongside synchronized respiratory, photoplethysmographic, and motion signals. Temporal changes will be characterized using overlapping 30-s windows advanced in 15-s steps. The primary outcome will be the overall 6-min linear slope of global prefrontal HbO. Differences among practices will be examined using a linear mixed-effects model adjusted for session period and sequence; models additionally incorporating respiratory, cardiac, and motion measures will be treated as sensitivity analyses. Secondary time-resolved and region-specific outcomes will be exploratory. This protocol provides a prespecified method for comparing fNIRS-derived prefrontal hemodynamic patterns during traditional mind-body practices, which may include residual systemic components.