Road cycle TT performance: Relationship to the power-duration model and association with FTP

Abstract

To determine the accuracy of critical power (CP) and Wʹ (the curvature constant of the power-duration relationship) derived from self-paced time-trial (TT) prediction trials using mobile power meters to predict 16.1-km road cycling TT performance. This study also aimed to test the agreement between functional threshold power (FTP) and CP. Methods: Twelve competitive male cyclists completed an incremental test to exhaustion, a 16.1-km road TT, an FTP test, and 4-5 self-paced TT bouts on a stationary bike within the lab, using mobile power meters. Results: CP and Wʹ derived from the power-duration relationship closely predicted TT performance. The 16.1-km road TT completion time (26.7 ± 2.2 min) was significantly correlated with the predicted time-to-completion (27.5 ± 3.3 min, r= 0.89, P<0.01). CP and FTP were not significantly different (275 ± 40 W vs. 278 ± 42 W, P>0.05); however, the limits of agreement between CP and FTP were 30 to-36 W. Discussion: The findings of this study indicate that CP and Wʹ determined using mobile power meters during maximal, self-paced TT prediction trials can be used to accurately predict 16.1-km cycling performance, supporting the application of the CP and Wʹ for performance prediction. However, whilst we demonstrated that the FTP was not significantly different from CP, the limits of agreement were too large to consider FTP and CP interchangeable.

Maximal Lactate Steady State Versus the 20-Minute Functional Threshold Power Test in Well-Trained Individuals: “Watts” the Big Deal?

“…While the present study adopted MLSS as the criterion measure for the upper limit of metabolic stability and compared this with the FTP95%, other studies have investigated the correspondence between FTP tests and different markers of critical intensity. For example, Morgan et al 9 , found a close relationship between CP (275 ± 42W) and FTP95% (278 ± 42W). However, similar to our results, they found that the corresponding limits of agreement (+10.9% to 13.1%) exceeded those that would allow the two measures to be used interchangeably with a high level of confidence.…”

“…This is pertinent as many regard MLSS to be the criterion measure for tolerable exercise 2 . Furthermore, although cross-sectional comparisons between FTP95% and other markers of performance have been made [5][6][7]9 , no study has evaluated the ability or sensitivity of the FTP95% test to track changes in fitness level on a longitudinal basis.…”

Reliability of the Functional Threshold Power in Competitive Cyclists

“…adopted the "even" [17] or "parabolic-shaped" [12,13] pacing strategy. Therefore, we believe that the pacing strategy for the 20min TT was modulated by the long warm-up and by the [La] before the start of the TT (4.9 ± 2.6 and 4.8 ± 2.5 mmol L − 1 ; test-retest, respectively).…”

“…To the best of our knowledge, Borszcz et al [7,8] and Valenzuela et al [10] are the only studies that have used the warm-up recommended by the authors [6]. Others have not used this section of the protocol [11][12][13]. Borszcz et al [7] reported high blood lactate concentrations ([La]) before the start of the test (6.5 ± 2.9 mmol • L − 1 ).…”

“…Therefore, the FTP 20 warm-up protocol is not in accordance with the recent warm-up guidelines, which suggested a duration of about 20 min and a [La] of < 3 mmol • L − 1 at the end [14]. Additionally, cyclists adopted a conservative pacing strategy at the start of a TT in a recent research [7], despite the fast start strategy presented in several TTs with durations that range from 4 to 60 min [7,12,13,[15][16][17][18][19].…”