A dynamic model of the bi-exponential reconstitution and expenditure of W′ in trained cyclists

ABSTRACT

The aim of this study was to investigate the effects of different recovery power outputs on the reconstitution of W′ and to develop a dynamic bi-exponential model of W′ during depletion and reconstitution. Ten trained cyclists (mass 71.7 ± 8.4 kg; V̇O_2max 60.0 ± 6.3 ml·kg⁻¹·min⁻¹) completed three incremental ramps (20 W·min⁻¹) to the limit of tolerance on each of six occasions with recovery durations of 30 and 240 s. Recovery power outputs varied between 50 W (LOW); 60% of critical power (CP) (MOD) and 85% of CP (HVY). W′ reconstitution was measured following each recovery and fitted to a bi-exponential model. Amplitude and time constant (τ) parameters were then determined via regression analysis accounting for relative intensity and duration to produce a dynamic model of W′. W′ reconstitution slowed disproportionately as recovery power output increased (p < 0.001) and increased with recovery duration (p < 0.001). The amplitudes of each recovery component were strongly correlated to W′ reconstitution after 240 s at HVY (r = 0.95), whilst τ parameters were found to be related to the fractional difference between recovery power and CP. The predictive capacity of the resultant model was assessed against experimental data with no differences found between predicted and experimental values of W′ reconstitution (p > 0.05). The dynamic bi-exponential model of W′ accounting for varying recovery intensities closely described W′ kinetics in trained cyclists facilitating real-time decisions about pacing and tactics during competition. The model can be customised for individuals from known CP and W′ and a single additional test session.

Highlights

• A dynamic bi-exponential model of W′ accounting for both varying power output and duration.

• Individual customisation of the model can be achieved with a single specific test session.

• W′ reconstitution slows disproportionally with increasing intensity after repeated bouts.

KEYWORDS:

• Critical power
• recovery
• W′
• modelling
• fatigue

Acknowledgements

The authors would like to thank all the participants of the study.

Author contributions

AC conceived and designed research. AC conducted experiments. AC, SM and KL analysed and interpreted the data, and contributed to the manuscript. All authors read and approved the manuscript.

Availability of data and material

Data is available upon request from the corresponding author.

Consent to participate

Informed consent to participate was obtained from all individual participants included in the study.

Consent for publication

Informed consent to publish was obtained from all individual participants included in the study.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.