A new incremental test for VO₂max accurate measurement by increasing VO₂max plateau duration, allowing the investigation of its limiting factors.

The purpose of this study was to (1) validate a new exercise protocol for accurate measurement of VO(2max) by obtention of a VO(2max) plateau for all subjects fit and unfit (2) test the hypothesis that VO(2max) plateau duration is not correlated with VO(2max) and (3) verify that limiting factors of VO(2max) plateau duration are different from those of VO(2max) amplitude. Therefore, 14 subjects performed two incremental cycling tests: (1) a classical incremental test (CIT) to determine VO(2max), the power at VO(2max) (PVO(2max)) and at the lactate threshold (PLT) (2) a new incremental test (NIT) in which the power was decreased just after the subject reached VO(2max). During both protocols, heart rate, stroke volume, cardiac output, the arterio-venous difference and the oxygen blood saturation were recorded. The results showed that, with the NIT, subject could maintain a long VO(2max) plateau (6 ± 3 min), even those who could not reach VO(2max) plateau at the end of CIT (n = 5). The VO(2max) plateau duration was not correlated with VO(2max) amplitude which was correlated with the power at SV(max) (r = 0.888, p < 0.001). The VO(2max) plateau duration was correlated with the power decrease (W/s) during the VO(2max) plateau (r = -0.72, p = 0.003) but not with cardiac-related factors nor with PVO(2max). In conclusion, these experiments showed that it was possible to get a long VO(2max) plateau at the end of NIT whatever the individual VO(2max) amplitude was. The limiting factor of VO(2max) duration was the power output.