Does Standing on a Cycle-ergometer, Towards the Conclusion of a Graded Exercise Test, Yield Cardiorespiratory Values Equivalent to Treadmill Testing?

Graded exercise testing (GXT), per a cycle-ergometer (CE), offers safety and monitoring advantages over treadmill (TM) GXT. Unfortunately, CE-VO2max and some other cardiorespiratory (CR) variables are frequently lower than TM-GXT values. It has been difficult to compare TM and CE-GXT values. However, it was hypothesized that standing towards the conclusion of the CE-GXT (Stand-CE) might increase CE values to those equal to TM-GXT. If Stand-CE and TM-GXT CR values were equal, Stand-CE-GXT could become the method of choice for GXT for the general population. The purpose of this investigation was to investigate the effect of Stand-CE on CR variables. An intentionally diverse sample (N = 34, 24 males and 10 females, aged 18-54 y, with VO2max values 25-76 ml/kg/min) representing the "apparently healthy" general population participated. Volunteers completed two GXT trials, one per TM (Bruce protocol) and the other per a MET-TM-matched CE-GXT where initially seated participants stood and pedaled after their respiratory exchange ratio (RER) reached 1.0. Eighteen participants underwent a third MET-TM-matched trial where they remained seated throughout GXT (Sit-CE). Trials were counter-balanced with at least 48 h between GXT. There were significant statistical differences (p < 0.05) between TM and Stand-CE per matched-samples T-test (N = 34) on the following variables: VEmax (TM = 115 ± 24.4 l/min, Stand-CE = 99.4 ± 28.1), VCO2max (TM = 4.26 ± 0.9 l/min, Stand-CE = 3.56 ± 0.84), VO2max (TM = 44.9 ± 9.1 ml/kg/min, Stand-CE = 39.3 ± 9.0), METSmax (TM = 12.8 ± 2.6 METS, Stand-CE = 11.2 ± 2.5), and HRmax (TM = 175 ± 13 bpm, Stand-CE = 166 ± 12). One-way repeated measures ANOVA (N = 18) demonstrated no statistical differences among all trials: VEmax (TM = 112.8 ± 25.3 l/min, Stand-CE = 102.3 ± 25.2, Sit-CE = 107.3 ± 33.1), VCO2max (TM = 4.17 ± 0.99 l/min, Stand-CE = 3.62 ± 0.80, Sit-CE = 3.55 ± 0.83), VO2max (TM = 47.1 ± 9.8 ml/kg/min, Stand-CE = 42.0 ± 9.0, Sit-CE = 43.3 ± 8.9), METSmax (TM = 13.5 ± 2.8 METS, Stand-CE = 12.0 ± 2.6, Sit-CE = 12.4 ± 2.5), and HRmax (TM = 176 ± 13 bpm, Stand-CE = 171 ± 12, Sit-CE = 173 ± 11). Results of this investigation suggest that TM-GXT CR values are larger than Stand-CE, and Stand-CE values are not different from Sit-CE. Future studies will test validity of these findings per gender, aerobic training status, in populations that are highly skilled with TM and CE (tri-athletes), children, the elderly, and diseased populations.