Critical Power Measurement
Bibliographic record
Abstract
Critical Power (CP) represents the highest sustainable power output (PO) at which physiological steady-state can be achieved.. In cycling exercise, CP is traditionally derived from the PO versus time-to-exhaustion (TTE) relationship based on 3-5 TTE trials ranging from 1 to 20 min. Recently, a 3-min all-out test (3M) has been proposed for CP estimation. However, CP derived from this test has not been externally validated (i.e., corroborating steady-state lactate concentration [La] for prolonged durations of cycling at the value associated to CP). PURPOSE:To compare CP derived from 5 TTE and the 3M test, and to validate these values against a maximal lactate steady-state (MLSS) test. METHODS:Seven healthy young subjects (28±3 yrs; 68.4±7.3 kg; 175±9 cm) were tested. A ramp incremental test to exhaustion was performed on a cycle ergometer (Velotron Dynafit Pro, Racer Mate, Seattle, WA, USA) to determine VO2peak, gas exchange threshold (GET) (Quark CPET, Cosmed, Rome, Italy), and peak power output (POpeak). CP from the 5 TTE test was calculated with a 2-parameter hyperbolic model (HYP). The 3M test was performed using the linear mode of the cycle ergometer, and CP was calculated as the mean PO of the last 30 s of the test. MLSS was considered as the highest PO during a 30-min constant load ride with a variation in [La] ≤ 1.0 mM·L-1 between the last 20 min of exercise ([La] measured every 5 min). RESULTS:Mean VO2peak, GET, and POpeak were 4.30±0.67 L·min-1, 2.60±0.30 L·min-1, and 383±53 W, respectively. PO at CP HYP (267±39 W), CP 3M (258±52 W), and MLSS (246±37) were not different (p>0.05). Bland-Altman plots comparing CP from HYP and 3M against the PO at MLSS showed no significant biases but wide limits of agreement (LOA) ranging from -8 to 51 W (bias=21 W) and from -43 to 68 W (bias=13 W), for HYP and 3M, respectively. When comparing CP from 3M to HYP, the LOA ranged from -43 to 26W (bias=-9 W). CONCLUSIONS:Although the POs associated to CP as estimated from the 5 TTE, the 3-min all-out test, and MLSS were not different, the large variability in the CP amongst methods results in poor accuracy of CP estimation and detracts from the practical application of this test.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.009 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.006 | 0.004 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.003 | 0.002 |
| Open science | 0.003 | 0.003 |
| Research integrity | 0.002 | 0.001 |
| Insufficient payload (model declined to judge) | 0.075 | 0.032 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".