In this study, three breathing conditions, normal breathing, abdominal breathing, and apnea, were tested to identify relaxation methods for pain reduction. Pain was induced in healthy male subjects by passive straight-leg raising (SLR) stretches, muscle tone was assessed using muscle hardness and SLR angle indices, and pain and relaxation were evaluated using Numerical Rating Scale (NRS), Pamin, and electroencephalography (EEG) indices. We predicted that abdominal breathing would correlate with higher alpha wave band and relaxation degree during SLR stretch intervention, lower pain degree during SLR stretch intervention, and SLR angle widening due to reduced muscle tone after SLR stretch intervention. However, our results did not support our predicted outcomes. Notably, our findings suggest that normal and abdominal breathing tend to be more relaxing than apnea, and that increased alpha wave band activity via abdominal breathing may be necessary to cope with rapid pain cycles.