Thermal imaging as a tool of different breathing exercise characterization: a case study

INTRODUCTION Specific respiratory muscle training improves athletes’ performance particularly at high intensities (Esposito et al., 2010). The aim of this study was to evaluate two types of breathing, thoracic and diaphragmatic, used in respiratory training. METHODS An evaluation of different respiratory muscle training is possible by the use of IR thermography (AVIO, TVS-700), a non-invasive technique that visually represents the whole process during and after training (Merla et al., 2010). The subject performed the exercise with SpiroTiger® for 5 minutes, followed by a 5 minute recovery. The exercise was repeated 15 minutes after the end of recovery-time. Thoracic and diaphragmatic breathing exercises were performed using the same protocol in different days. Ten Regions of Interest (ROI) were selected following anatomical and functional correspondence with the muscles involved in breathing (Zaidi et al., 2007). The data were analyzed with specific thermal images software. RESULTS In order to check functional behaviour of respiratory muscles, we calculated the correlation coefficient (R) among thermal data of all the ROI and then grouped together ROI with strong correlation (R≥0.85). In thoracic exercises, correlated ROI were grouped into 4 areas corresponding to: pectoral muscles, rectus abdominus, intercostal muscles, abdominal oblique. In diaphragmatic exercises we found a strong correlation (R≥0.96) between thermal data of all the ROI. The temperature of the torso decreased by a few degrees during both trainings, but there was also an increase in pectoral muscles areas to be considered. DISCUSSION ROI of pectoral muscles in thoracic breathing are characterized by a linear heating during exercise and also a linear trend in the cooling-down process during the recovery time. The heating-up is linked to the work of the superficial muscles located in the upper part of the trunk that characterized the thoracic breathing. In diaphragmatic breathing, which mainly uses internal musculature, temperature does not increase in pectoral muscles areas. There is in fact a lesser contribution of superficial muscles used in thoracic breathing. In diaphragmatic breathing, more muscles synergistically participate to carry out an action: this is the reason for the strong correlation between the thermal data of all the areas. REFERENCES Esposito F., Limonta E., Alberti G., Veicsteinas A., Ferretti G. (2010). Respir. Physiol. Neurobiol. 170:268-272. Merla, A., Mattei Peter A., Di Donato L., Romani G. (2010). Ann. Biomed. Eng. 38:158–163. Zaidi H., Taiar R., Fohanno S., Polidori G. (2007). Acta Bioeng. Biomech. 9:47-51.