RESUMO
(Object) We, in collaboration with Wacoal Corp., assessed the effects of human hemoglobin dynamics associated with pressure stimulus applied by half-ovoid protrusions lined on brassiere straps, which were developed with an intended use by females to safely alleviate shoulder stiffness and associated pain in a convenient manner, and compared them to those of conventional flat and round magnets (5 mm in diameter, 800 Gauss).<BR>(Method) Six healthy females volunteered for each of the four experiments. The participants'thoracic circumference or band size was 70 cm (B70) for experiments one and two, and 80 cm (B80) for three and four. For experiments one and three, we obtained the control hemoglobin (Hb) values, by near-infrared spectroscopy, 20 minutes after participants had worn brassieres with the newly developed straps turned inside out;and were compared to the values obtained after the straps were worn with protrusions pressing down on the skin (Protrusion-lined Strap Group, PST). For experiments two and four, the control Hb values were obtained after the participants had worn generic brassiere straps, and were compared to Hb values obtained after the magnet-lined straps were worn (Magnet-lined Strap Group, MSG).<BR>(Result) In the PSG (B70 &B80), both Oxy-Hb and Total-Hb values increased by stimulation with a 5%significant difference;however, no significant increase was observed in the MSG (B70 &B80). There was no significant difference depending on the band size.<BR><BR>(Discussion) In the present study, the post-stimulation increase of Hb values showed significant differences in PSG as a result of stimulation by protrusions. Stimulation by flat magnets demonstrated no such significance on Hb values, presumably due to the lower pressure to the skin. Stimulation by magnets showed no significant changes in total Hb values despite prior reports of it accelerating the blood flow. The shape with which pressure is applied against the skin may have relevance to the effect of stimulation.<BR>Protrusions left post-stimulation depression marks and flare on the skin surface, suggesting the possible involvement of mechanothermal polymodal receptors.<BR>(Conclusion) Stimulation with the protrusions we developed increased Hb values, showing a regional concentration of hemoglobin. This suggests that it is effective in alleviating shoulder stiffness and associated pain, and lining brassiere straps with the protrusions provides a means for females to self-apply such stimulation safely and conveniently.