Calculating critical power and the finite work capacity from a single all-out cycling test

Student thesis: Doctoral Thesis

Abstract

Critical power (CP) is an important training threshold and represents the highest power output that elicits steady-state physiological responses. Research suggests that CP and the finite work capacity (W'), can be estimated from a single 3-min bout of all-out cycling. Five experimental studies were undertaken to explore the reliability and validity of CP tests, and to propose a novel all-out testing protocol. Study one investigated the reliability and validity of the 3-min cycling test when performed against a fixed resistance and in isokinetic mode. Results suggested that the 3-min cycling test provided a reliable and valid estimate of CP in isokinetic mode, but significantly overestimated CP when performed against a fixed resistance. Study two investigated the effect of cadence on CP and W' during the 3-min cycling test when performed against a fixed resistance, with results suggesting that a better estimation of CP is observed at higher cadences (e.g. preferred cadence +10 revĀ·min-1). Studies three and four focused on measuring power output using cycle-mounted power meters to support the novel all-out testing protocol used in study five. The PowerTap P1 pedals demonstrated greater reliability and validity than the Garmin Vector 2 pedals across all power outputs, with reliability maintained after prolonged use. Consequently, the PowerTap P1 pedals were used in study five, which investigated the reliability and validity of a novel all-out cycling test to estimate CP and W'. Results suggested that CP could be estimated from the novel all-out cycling test; however, caution should be taken when estimating W'. The results also suggested that cycling at CP calculated from the original protocol, 3-min cycling test protocol, and novel all-out test protocol resulted in exhaustion occurring within 20 min, and a metabolic steady-state was not observed. The overall findings of this thesis question the underpinning physiology of CP, and whether CP represents the boundary between the heavy and severe exercise intensity domains.
Date of AwardFeb 2019
Original languageEnglish
Awarding Institution
  • Solent University

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