Non-exhaustive double effort test is reliable and estimates the first ventilatory threshold intensity in running exercise

Purpose: The present study aimed to investigate the reliability of the non-exhaustive double effort (NEDE) test in running exercise and its associations with the ventilatory thresholds (VT1 and VT2) and the maximal lactate steady state (MLSS). Methods: Ten healthy male adults (age: 23 4 years, height: 176.6 +/- 6.4 cm, body mass: 76.6 +/- 10.7 kg) performed 4 procedures: (1) a ramp test for VT1 and VT2 determinations measured by ratio of expired ventilation to O-2 uptake (VENO2) and expired ventilation to CO2 output (VENCO2) equivalents, respectively; (2) the NEDE test measured by blood lactate concentration (NEDELAC) and heart rate responses (NEDEHR); (3) a retest of NEDE for reliability analysis; and (4) continuous efforts to determine the MLSS intensity. The NEDE test consisted of 4 sessions at different running intensities. Each session was characterized by double efforts at the same running velocity (El and E2, 180 s), separated by a passive recovery period (90 s rest). LAC and HR values after El and E2 (in 4 sessions) were used to estimate the intensity equivalent to "null delta" by linear fit. This parameter represents, theoretically, the intensity equivalent to maximal aerobic capacity. Results: The intraclass correlation coefficient indicated significant reliability for NEDELAC (0.93) and NEDEHR (0.79) (both p < 0.05). There were significant correlations, no differences, and strong agreement with the intensities predicted by NEDELAC (10.1 1.9 km/h) and NEDEHR (9.8 +/- 2.0 km/h) to VT1 (10.2 +/- 1.1 km/h). In addition, despite significantly lower MLSS intensity (12.2 +/- 1.2 km/h), NEDELAC and NEDEHR intensities were highly correlated with this parameter (0.90 and 0.88, respectively). Conclusion: The NEDE test applied to running exercise is reliable and estimates the VT1 intensity. Additionally, NEDE intensities were lower but still correlated with VT2 and MLSS. (C) 2018 Published by Elsevier B.V. on behalf of Shanghai University of Sport.