Respiratory modulation of neurophysiology and symptoms in athletes with sports-related concussion: a randomized...

This study examined the effects of two breathing interventions on athletes with persistent post-concussive symptoms. Resonance breathing (RB) is a slow breathing technique at an individual's resonance frequency. Pelvic floor resonance breathing (PRB) combines diaphragmatic breathing with pelvic floor muscle activation.

A randomized crossover trial was conducted using a 3-1-3 week design. Two intervention phases were separated by a 1-week washout period. Twenty-six male rugby athletes with persistent post-concussive symptoms were included. Participants were assigned to different intervention sequences. Outcomes included the Rivermead Post-Concussion Symptoms Questionnaire, electroencephalography (EEG), heart rate variability (HRV), and skin sympathetic nerve activity (SKNA). Measurements were taken at baseline and after each intervention.

Total symptom scores decreased after both interventions (p < 0.01). Somatic symptom scores were lower after PRB (p < 0.05), whereas emotional symptom scores were lower after RB (p < 0.05). EEG results showed different pre-post patterns between interventions. PRB was associated with broader pre-post changes in β and θ bands, whereas RB showed more localized pre-post changes in β, θ, and δ bands. Heart rate was lower and HRV total power was higher after both interventions (p < 0.05). The LF/HF ratio and SKNA burst area were higher after RB (p < 0.05), whereas SKNA burst threshold and frequency were higher after PRB (p < 0.05). Correlation analysis suggested an association between prefrontal activity and SKNA changes in PRB.

Both RB and PRB were associated with symptom improvement and changes in neuro-autonomic function. The two interventions showed different patterns. These findings support the use of breathing interventions as non-pharmacological approaches in concussion rehabilitation.