High Agreement between Laboratory and Field Estimates of Critical Power in Cycling

Abstract

Karsten, B., Jobson, S. A., Hopker, J., Jimenez, A., Beedie, C. (2014). High Agreement between Laboratory and Field Estimates of Critical Power in Cycling. International Journal of Sports Medicine, 35 (4), 298-303The purpose of this study was to investigate the level of agreement between laboratory-based estimates of critical power (CP) and results taken from a novel field test. Subjects were fourteen trained cyclists (age 40 +/- 7 yrs; body mass 70.2 +/- 6.5 kg; O-2max 3.8 +/- 0.5 L center dot min(-1)). Laboratory-based CP was estimated from 3 constant work-rate tests at 80%, 100% and 105% of maximal aerobic power (MAP). Field-based CP was estimated from 3 all-out tests performed on an outdoor velodrome over fixed durations of 3, 7 and 12 min. Using the linear work limit (W-lim) vs. time limit (T-lim) relation for the estimation of CP1 values and the inverse time (1/t) vs. power (P) models for the estimation of CP2 values, field-based CP1 and CP2 values did not significantly differ from laboratory-based values (234 +/- 24.4 W vs. 234 +/- 25.5 W (CP1); PpublishersversionPeer reviewe

Validity and reliability of critical power field testing

“…We found a high agreement for CP but not for W when comparing laboratory and velodrome environments. However reported values for LoA of CP in the present study (table 1a, experiment 2) are not as high as in our velodrome study (Karsten et al 2013), which possibly demonstrates an influence of terrain on CP.…”

“…CoV values for experiment 1 ranged between 2.2% and 2.5%, for experiment 2 the range was between 5.9% and 7.0% and for experiment 3 it was between 3.3% and 3.6% ( Gonzales-Haro et al (2007). Our recent study (Karsten et al 2013) reported similar mean differences of 2 ± 8 W with LoA between 11 W and 17 W and SEE values of 2.5% to those in this current study when comparing CP determined in the laboratory with CP determined from the track. We therefore suggest that the experimental protocols can be considered to be acceptable when testing CP in the field.…”

“…These tests have to be performed regularly to ensure that the training performed is achieving targeted adaptations. Recently, we have demonstrated that CP has a field application, by comparing CP obtained in the laboratory with that from testing in a velodrome and found low standard error of estimates (SEE; 2.5%), and a good level of agreement (LoA; between the two environments (Karsten et al 2013). Conversely, in agreement with previous literature (Green 1994), W (defined as an athlete's ability to exercise under increasing levels of fatigue caused by its own utilisation (Ferguson et al 2010)) resulted in low LoA and high SEE values between the laboratory and field testing protocol (Karsten et al 2014).…”

Prediction of Critical Power and W′ in Hypoxia: Application to Work-Balance Modelling

“…Using an average confidence interval across all trials, we estimated that a significant decrease in W′ would occur at altitudes beyond ≈3,500 m. Simpson et al (2015) reported a small decrease in W′ at 3,800 m, but this did not reach statistical significance, whilst Valli et al (2011) found a large decrease (≈55%) in W′ at 5,050 m. Thus, it appears likely that severe hypoxia reduces W′, yet some uncertainty remains regarding the lowest altitude at which this occurs. Measurement of W′ shows high within-subject variability (Karsten et al, 2014) though, which may confound attempts to accurately determine such a threshold altitude. Valli et al (2011) suggested the decrease in W′ was consistent with reduced muscle-venous O 2 storage.…”

“…The CP test was equivalent to that described and validated by Karsten et al (2014, 2016). This protocol consists of three TT efforts lasting 12, 7, and 3 min in descending order, interspersed with 30 min of active recovery.…”