Effect of breathing type on electromyographic activity of respiratory muscles during tooth clenching at different decubitus positions

Objective: To compare the effect of breathing type on electromyographic (EMG) activity of respiratory muscles during tooth clenching at different decubitus positions. Methods: Forty young men participants were included, 11 with upper costal, 9 with mixed, and 20 with costo-diaphragmatic breathing type. EMG recordings of diaphragm (DIA), external intercostal (EIC), sternocleidomastoid (SCM), and latissimus dorsi (LAT) muscles during tooth clenching in the intercuspal position were performed in dorsal, left lateral, and ventral decubitus positions. Results: DIA EMG activity was higher in subjects with upper costal or mixed than with costodiaphragmatic breathing type (p = 0.006; 0.021, respectively), whereas it was similar between upper costal and mixed breathing types. EIC, SCM, and LAT activity was similar among breathing types. Conclusion: Higher DIA activity would be a risk factor to exceed the adaptive capability of healthy subjects with upper costal or mixed breathing type.