Individual SMR neurofeedback responsiveness during a single session and its associations with autonomic regulation and shooting performance in elite rifle athletes.

INTRODUCTION: Sensorimotor rhythm (SMR) neurofeedback has attracted growing interest for improving performance in precision sports; however, inter-individual variability in responsiveness remains poorly understood, and its associations with autonomic regulation and shooting performance have not been examined within a single-session paradigm. Because a substantial proportion of trainees show limited ability to self-regulate EEG activity ("non-responders"), characterizing responsiveness is important for developing personalized protocols. This exploratory study aimed to characterize individual differences in SMR neurofeedback responsiveness during a single session and examine their associations with post-training autonomic regulation and shooting performance in elite air rifle athletes. METHODS: Thirteen elite air rifle shooters completed a single 10-min SMR (12-15 Hz) neurofeedback session at electrode site Cz. Heart rate variability (HRV) was recorded at four timepoints spanning pre- and post-shooting and pre- and post-training rest. Shooting performance was assessed via the SCATT system across two 30-shot blocks. Individual SMR regulation trajectories were indexed as linear amplitude slopes across five training blocks. Athletes were classified as Responders (slope > 0; n = 9) or Non-Responders (slope ≤0; n = 4) reflecting whether SMR amplitude showed a net increase or decrease across training. RESULTS: SMR slope showed the strongest associations with changes in shooting score (r = 0.623) and logLF (r = -0.636), though neither survived Benjamini-Hochberg FDR correction (both q = 0.248). Responders exhibited larger post-training increases in DFA α2 (a long-term scaling exponent derived from detrended fluctuation analysis reflecting autonomic regulatory complexity; d = 1.688, p = 0.017) and larger decreases in logLF (d = 1.654, p = 0.019) than Non-Responders, though neither survived FDR correction. No baseline HRV (all p > 0.09) or subjective engagement (all p > 0.21) differences were observed between groups. DISCUSSION: These preliminary, exploratory findings suggest that individual SMR regulatory capacity may relate to post-training autonomic modulation and shooting performance, and that SMR amplitude slope may represent a promising index of neurofeedback learning. Given the small and unequal responder groups (n = 9 vs. 4) and the absence of a sham or control condition, these associations should be interpreted as hypothesis-generating rather than confirmatory, warranting replication in larger, controlled samples.