The ramp and all-out exercise test to determine critical power: validity and robustness to manipulations in body position

European Journal of Applied Physiology https://doi.org/10.1007/s00421-021-04739-9 ORIGINAL ARTICLE The ramp and all‑out exercise test to determine critical power: validity and robustness to manipulations in body position Richie P. Goulding1 · Denise M. Roche2 · Simon Marwood2 Received: 16 January 2021 / Accepted: 8 June 2021 © The Author(s) 2021 Abstract Purpose The purpose of the present study was to determine whether a contiguous ramp and all-out exercise test could accurately determine critical power (CP) in a single laboratory visit during both upright and supine cycle exercise. Methods Healthy males completed maximal ramp-incremental exercise on a cycle ergometer in the upright (n = 15) and supine positions (n = 8), with task failure immediately followed by a 3-min all-out phase for determination of end-test power (EP). On separate days, participants undertook four constant-power tests in either the upright or supine positions with the limit of tolerance ranging from ~ 2 to 15 min for determination of CP. Results During upright exercise, EP was highly correlated with (R 2 = 0.93, P < 0.001) and not different from CP (CP = 221 ± 40 W vs. EP = 226 ± 46 W, P = 0.085, 95% limits of agreement − 30, 19 W). During supine exercise, EP was also highly correlated with (R2 = 0.94, P < 0.001) and not different from CP (CP = 140 ± 42 W vs. EP = 136 ± 40 W, P = 0.293, 95% limits of agreement − 16, 24 W). Conclusion The present data suggest that EP derived from a contiguous ramp all-out exercise test is not different from the gold-standard method of CP determination during both upright and supine cycle exercise when assessed at the group level. However, the wide limits of agreement observed within the present study suggest that EP and CP should not be used interchangeably. Keywords Critical power · All-out exercise · Power–duration relationship · Exercise testing · Performance Abbreviations %Δ Percentage difference between gas exchange threshold and maximal oxygen uptake ANOVA Analysis of variance CP Critical power CV Coefficient of variation EP End-test power GET Gas exchange threshold LoA Limits of agreement P Power SD Standard deviation SEE Standard error of the estimate Communicated by I. Mark olfert. * Richie P. Goulding 1 Laboratory for Myology, Vrije Universiteit, O|2 Labgebouw, De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands 2 School of Health Sciences, Liverpool Hope University, Liverpool, UK T Time V̇ O2 Pulmonary oxygen uptake V̇ O2max Maximal oxygen uptake W Work W′ Work capacity available above critical power WEP Work performed above end-test power Introduction The relationship between power and time to task failure during cycle exercise over durations spanning ~ 2–30 min is well-described by a hyperbolic function (Poole et al. 2016). This power–time relationship is defined by two parameters: critical power (CP); representing the power asymptote of the hyperbola, and W′; the curvature constant of the hyperbola representing a finite amount of work that can be performed above CP (Fukuba et al. 2003). CP represents an important parameter of aerobic function (Poole et al. 1988); separating exercise intensities where a steady state is attainable for pulmonary oxygen uptake (V̇ O2) and muscle metabolites (i.e. 13 Vol.:(0123456789) European Journal of Applied Physiology “heavy” intensity domain) from intensities where a steady state is unattainable (i.e. “severe” intensity domain) (Poole et al. 1988; Jones et al. 2008). During sustained exercise above CP, therefore, pulmonary V̇ O2 is driven towards its maximal value (V̇ O2 max) (Poole et al. 1988), intramuscular phosphocreatine projects towards a nadir (Jones et al. 2008), and exercise tolerance is predictably limited (Poole et al. 2016). CP and W′ are both sensitive to exercise training (Gaesser and Wilson 1988; Poole et al. 1990; Jenkins and Quigley 1992; Vanhatalo et al. 2008a) and offer an accurate prediction of endurance performance within the task duration range of ~ 2–30 min, underscoring the importance of these parameters as determinants of endurance performance. Moreover, elite male runners typically sustain 96% of their critical speed (analogous to CP) over the course of a marathon (Jones and Vanhatalo 2017), and critical speed is predictive of marathon performance across a range of abilities (Smyth and Muniz-Pumares 2020). CP and W′ therefore provide invaluable information to endurance performance athletes, coaches and practitioners regarding the physiological and mechanical performance capabilities of an athlete, as well as the efficacy of a given training intervention or ergogenic aid. However, the conventional approach for establishment of CP and W′ requires undertaking 3–5 constant load prediction trials to the limit of tolerance, ideally on separate days, such that confident estimates of the parameters may be obtained (Muniz-Pumares et al. 2018). Precise determination of CP is therefore both time- and labour-intensive for researchers and practitioners alike. The power–duration relationship predicts that when W′ has been fully depleted (i.e. at task failure), the highest power output that can be sustained is CP (Coats et al. 2003; Chidnok et al. 2013). Hence, Vanhatalo et al. (2007) demonstrated that during the final 30 s of an all-out 3-min bout of cycle exercise, power output plateaued to a work rate that was not different from, and highly correlated with, CP (i.e. end-test power; EP). More recently, Murgatroyd et al. (2014) demonstrated that CP could be accurately and reliably determined from the EP attained during a single exercise test, incorporating a 3-min all-out bout of exercise performed immediately following task failure during a maximal rampincremental exercise test, whereas W′ was underestimated by the work above EP (WEP). This approach represents a significant advance over 1- (Clark et al. 2013) or 2-day (Vanhatalo et al. 2007; Bergstrom et al. 2012) testing procedures, because additional parameters of aerobic function (i.e., the gas exchange threshold, GET; mean response time of V̇ O2 kinetics; V̇ O2max) and thus the boundaries between moderate, heavy, and severe exercise intensity domains can be determined in a single visit. However, the validity of this test has not been confirmed by more than one study (Murgatroyd et al. 2014), nor have the robustness of its underlying 13 principles been tested using alternative exercise modes. For instance, if EP from the contiguous ramp all-out test can be demonstrated to provide a valid estimate of CP and W′ in an alternative mode of exercise (e.g. supine exercise), this would provide further evidence of the robustness of the underlying principles of this approach for the determination of CP. Such an approach would considerably reduce the burden associated with determination of the power-time parameters for sports and exercise practitioners. The aim of this study was therefore to determine whether the contiguous (...truncated)