Child–adult differences in the kinetics of torque development
Bibliographic record
Abstract
Children have lower size-normalised maximal voluntary force, speed, and power than adults. It has been hypothesised that these and other age-related performance differences are due to lesser type-II motor-unit utilisation in children. This should be manifested as slower force kinetics in explosive muscle contractions. The purpose of this study was to investigate the nature of child-adult force-kinetics differences and whether the latter could support that hypothesis. Untrained boys (n = 20) and men (n = 20) (10.1 ± 1.3 and 22.9 ± 4.4 years, respectively), performed maximal, explosive, isometric elbow flexions and knee extensions on a Biodex dynamometer. Peak torque (MVC), times to 10-100% MVC, and other kinetics parameters were determined. The boys' body-mass-normalised knee extension MVC, peak rate of torque development, and %MVC at 100 ms were 26, 17 and 23% lower compared with the men and their times to 30% and 80% MVC were 24 and 48% longer, respectively. Elbow flexion kinetics showed similar or greater differences. The findings illuminate boys' inherent disadvantage in tasks requiring speed or explosive force. It is demonstrated that the extent of the boys-men kinetics disparity cannot be explained by muscle-composition and/or musculo-tendinous-stiffness differences. We suggest therefore that the findings indirectly support children's lower utilisation of type-II motor units.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 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 | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".