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Jason C. Bartram, Dominic Thewlis, David T. Martin and Kevin I. Norton

Purpose:

New applications of the critical-power concept, such as the modeling of intermittent-work capabilities, are exciting prospects for elite cycling. However, accurate calculation of the required parameters is traditionally time invasive and somewhat impractical. An alternative single-test protocol (3-min all-out) has recently been proposed, but validation in an elite population is lacking. The traditional approach for parameter establishment, but with fewer tests, could also prove an acceptable compromise.

Methods:

Six senior Australian endurance track-cycling representatives completed 6 efforts to exhaustion on 2 separate days over a 3-wk period. These included 1-, 4-, 6-, 8-, and 10-min self-paced efforts, plus the 3-min all-out protocol. Traditional work-vs-time calculations of CP and anaerobic energy contribution (W′) using the 5 self-paced efforts were compared with calculations from the 3-min all-out protocol. The impact of using just 2 or 3 self-paced efforts for traditional CP and W′ estimation was also explored using thresholds of agreement (8 W, 2.0 kJ, respectively).

Results:

CP estimated from the 3-min all-out approach was significantly higher than from the traditional approach (402 ± 33, 351 ± 27 W, P < .001), while W′ was lower (15.5 ± 3.0, 24.3 ± 4.0 kJ, P = .02). Five different combinations of 2 or 3 self-paced efforts led to CP estimates within the threshold of agreement, with only 1 combination deemed accurate for W′.

Conclusions:

In elite cyclists the 3-min all-out approach is not suitable to estimate CP when compared with the traditional method. However, reducing the number of tests used in the traditional method lessens testing burden while maintaining appropriate parameter accuracy.

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Jason C. Bartram, Dominic Thewlis, David T. Martin and Kevin I. Norton

Purpose: With knowledge of an individual’s critical power and W′, the SKIBA 2 model provides a framework with which to track W′ balance during intermittent high-intensity work bouts. There are fears that the time constant controlling the recovery rate of W′ (τ W) may require refinement to enable effective use in an elite population. Methods: Four elite endurance cyclists completed an array of intermittent exercise protocols to volitional exhaustion. Each protocol lasted approximately 3.5–6 min and featured a range of recovery intensities, set in relation to the athlete’s critical power (D CP). Using the framework of the SKIBA 2 model, the τ W values were modified for each protocol to achieve an accurate W′ at volitional exhaustion. Modified τ W values were compared with equivalent SKIBA 2 τ W values to assess the difference in recovery rates for this population. Plotting modified τ W values against D CP showed the adjusted relationship between work rate and recovery rate. Results: Comparing modified τ W values against the SKIBA 2 τ W values showed a negative bias of 112 (46) s (mean ± 95% confidence limits), suggesting that athletes recovered W′ faster than predicted by SKIBA 2 (P = .0001). The modified τ WD CP relationship was best described by a power function: τ W = 2287.2 × D CP –0.688 (R 2 = .433). Conclusions: The current SKIBA 2 model is not appropriate for use in elite cyclists, as it underpredicts the recovery rate of W′. The modified τ W equation presented will require validation but appears more appropriate for high-performance athletes. Individual τ W relationships may be necessary to maximize the model’s validity.

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Matthew W. Driller, Christos K. Argus, Jason C. Bartram, Jacinta Bonaventura, David T. Martin, Nicholas P. West and Shona L. Halson

Purpose:

To determine the intraday and interday reliability of a 2 × 4-min performance test on a cycle ergometer (Wattbike) separated by 30 min of passive recovery (2 × 4MMP).

Methods:

Twelve highly trained cyclists (mean ± SD; age = 20 ± 2 y, predicted VO2max = 59.0 ± 3.6 mL · kg−1 · min−1) completed six 2 × 4MMP cycling tests on a Wattbike ergometer separated by 7 d. Mean power was measured to determine intraday (test 1 [T1] to test 2 [T2]) and interday reliability (weeks 1–6) over the repeated trials.

Results:

The mean intraday reliabilities of the 2 × 4MMP test, as expressed by the typical error of measurement (TEM, W) and coefficient of variation (CV, %) over the 6 wk, were 10.0 W (95% confidence limits [CL] 8.2–11.8), and 2.6% (95%CL 2.1–3.1), respectively. The mean interday reliability TEM and CV for T1 over the 6 wk were 10.4 W (95%CL 8.7–13.3) and 2.7% (95%CL 2.3–3.5), respectively, and 11.7 W (95%CL 9.8–15.1) and 3.0% (95%CL 2.5–3.9) for T2.

Conclusion:

The testing protocol performed on a Wattbike cycle ergometer in the current study is reproducible in highly trained cyclists. The high intraday and interday reliability make it a reliable method for monitoring cycling performance and for investigating factors that affect performance in cycling events.