Relationship Between Electromyogram Spectrum Parameters and the Tension-Time Index During Incremental Exercise in Trained Subjects.

The inspiratory muscle tension-time index T-T0.1(given by P-0.1/PI-max X T-I/T-TOT) could be used to reliably assess inspiratory muscle activity during exercise. So far, the correlation between the T(T0.1 )and diaphragmatic activity has not been measured and the T-T0.1 has not been compared with other measurements of the inspiratory muscle load such as the transdiaphragmatic pressure index or T-T0.1. In this study we hypothesize that the T-T0.1 measuring the mouth is a noninvasive reflection of the electromyographic activity of the diaphragm. We simultaneously measured T-T0.1 and surface EMG (SEMG) of 8 trained subjects at rest and during incremental exercise. The curvature of Tro 1 and the root mean square (RMS) follow the same trend during the incremental exercise with a significant correlation between T-T0.1 and surface EMG parameters (RMS; r = 0.81 p < 0.001 and MPF; r = 0.80 p < 0.001 respectively). We conclude that T-T0.1 measured as s an adequate noninvasive method reflects the diaphragmatic activity during incremental exercise in healthy subjects.