Purpose: To evaluate the predictive validity of critical power (CP) and the work above CP (W′) on cycling performance (mean power during a 20-min time trial; TT20). Methods: On 3 separate days, 10 male cyclists completed a TT20 and 3 CP and W′ prediction trials of 1, 4, and 10 min and 2, 7, and 12 min in field conditions. CP and W′ were modeled across combinations of these prediction trials with the hyperbolic, linear work/time, and linear power inverse-time (INV) models. The agreement and the uncertainty between the predicted and actual TT20 were assessed with 95% limits of agreement and a probabilistic approach, respectively. Results: Differences between the predicted and actual TT20 were “trivial” for most of the models if the 1-min trial was not included. Including the 1-min trial in the INV and linear work/time models “possibly” to “very likely” overestimated TT20. The INV model provided the smallest total error (ie, best individual fit; 6%) for all cyclists (305  W; 19.6 [3.6] kJ). TT20 predicted from the best individual fit-derived CP, and W′ was strongly correlated with actual TT20 (317  W; r = .975; P < .001). The bias and 95% limits of agreement were 4 (7) W (−11 to 19 W). Conclusions: Field-derived CP and W′ accurately predicted cycling performance in the field. The INV model was most accurate to predict TT20 (1.3% [2.4%]). Adding a 1-min-prediction trial resulted in large total errors, so it should not be included in the models.
Alfred Nimmerichter, Bernhard Prinz, Matthias Gumpenberger, Sebastian Heider, and Klaus Wirth
Bernhard Prinz, Dieter Simon, Harald Tschan, and Alfred Nimmerichter
Purpose: To determine aerobic and anaerobic demands of mountain bike cross-country racing. Methods: Twelve elite cyclists (7 males;
Bettina Karsten, Jonathan Baker, Fernando Naclerio, Andreas Klose, Antonino Bianco, and Alfred Nimmerichter
Purpose: To investigate single-day time-to-exhaustion (TTE) and time-trial (TT) -based laboratory tests values of critical power (CP), W prime (W′), and respective oxygen-uptake-kinetic responses. Methods: Twelve cyclists performed a maximal ramp test followed by 3 TTE and 3 TT efforts interspersed by 60 min recovery between efforts. Oxygen uptake () was measured during all trials. The mean response time was calculated as a description of the overall
Alfred Nimmerichter, Bernhard Prinz, Kevin Haselsberger, Nina Novak, Dieter Simon, and James G. Hopker
While a number of studies have investigated gross efficiency (GE) in laboratory conditions, few studies have analyzed it in field conditions. Therefore, the aim of this study was to analyze the effect of gradient and cadence on GE in field conditions.
Thirteen trained cyclists (mean ± SD age 23.3 ± 4.1 y, stature 177.0 ± 5.5 cm, body mass 69.0 ± 7.2 kg, maximal oxygen uptake [V̇O2max] 68.4 ± 5.1 mL ∙ min–1 ∙ kg–1) completed an incremental graded exercise test to determine ventilatory threshold (VT) and 4 field trials of 6 min duration at 90% of VT on flat (1.1%) and uphill terrain (5.1%) with 2 different cadences (60 and 90 rpm). V̇O2 was measured with a portable gas analyzer and power output was controlled with a mobile power crank that was mounted on a 26-in mountain bike.
GE was significantly affected by cadence (20.6% ± 1.7% vs 18.1% ± 1.3% at 60 and 90 rpm, respectively; P < .001) and terrain (20.0% ± 1.5% vs 18.7% ± 1.7% at flat and uphill cycling, respectively; P = .029). The end-exercise V̇O2 was 2536 ± 352 and 2594 ± 329 mL/min for flat and uphill cycling, respectively (P = .489). There was a significant difference in end-exercise V̇O2 between 60 (2352 ± 193 mL/min) and 90 rpm (2778 ± 431 mL/min) (P < .001).
These findings support previous laboratory-based studies demonstrating reductions in GE with increasing cadence and gradient that might be attributed to changes in muscle-activity pattern.