Determining Critical Power in Forearm Handgrip Exercise: Repeatability of a Single "All Out" Exercise Test
Bibliographic record
Abstract
Critical power (CP) is the maximal power output where oxygen uptake and metabolic markers can be maintained for an extended period of time without drifting to maximal values. Classically, CP is identified from several repeats of constant load exercise to exhaustion across a range of exercise intensities, resulting in a hyperbolic function: Tlim = W'/(P-CP), where Tlim is the time to exhaustion, P is the power output, CP is the asymptote often referred to as "critical power" and W' is the curvature constant. Recently it has been demonstrated that power/force/torque stabilizes by the final 30 s of single "all out" cycling or knee extension exercise bouts maintained for ∼3-5 min and this is strongly correlated with the traditional CP test value. However, the reproducibility of CP estimated from all out tests in forearm handgrip exercise is unknown. PURPOSE: To determine the reproducibility of CP estimated from single "all out" exercise bouts in forearm handgrip exercise. METHODS: 10 healthy subjects (8 male, 2 female), completed 3 maximal effort isometric handgrip exercise trials (1 familiarization, 2 experimental) on separate days. Exercise consisted of isometric forearm handgrip squeezing (1 s contraction - 2 s relaxation duty cycle) for 7 minutes (140 contractions) in the supine position with the arm at heart level. Maximal voluntary contraction (MVC; kg) was determined prior to the exercise trial. Subjects were required to attempt an MVC on every contraction, with visual feedback on force output provided continuously on a computer screen. Constant verbal encouragement was provided, but subjects were not aware of elapsed time. CP was calculated as the average peak contraction force during the last 30 s of the 2nd and 3rd all out handgrip trials. RESULTS: The within-subject trail to trial coefficient of variation (CV) was 7.02 ± 5.26 % (range 16.45-0.32%). CV was < 10% in 7/10 subjects. The test-retest correlation r2 was 0.95. The group-averaged end test CP was greater in the second trial (24.30 ± 8.17 kg vs. 22.50 ± 8.41 kg, p= 0.02). CONCLUSIONS: Estimates of forearm handgripping CP from short duration "all out" handgrip exercise bouts demonstrate acceptably low variability. However, the variability appears to be systematic, with higher estimates likely in the second trial.
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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 | 0.005 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
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".