Muscle fiber number in the biceps brachii muscle of young and old men
Bibliographic record
Abstract
We have compared the number of muscle fibers in the biceps brachii muscle (BB) of six old men (82.3 +/- 4.3 years) and six young men (21.2 +/- 1.9 years). Muscle fiber number was estimated by dividing the maximal area of the BB, determined with magnetic resonance imaging, by the mean fiber area of the BB determined in a muscle biopsy. The percentage of type II fibers in the BB ( approximately 60%) and the type I fiber area were not different between the groups. The BB area (-26%), type II fiber area (-24%), mean fiber area (-20%), and maximal voluntary contraction strength (MVC) of the elbow flexor muscles (-27%) were lower in the old than young group. However, the estimated number of muscle fibers was not significantly different between the young (253000) and old (234000) men. Consequently, the smaller BB area of the old men could be explained primarily by a smaller type II fiber size. These findings suggest that old age is not associated with a reduced number of muscle fibers in the BB. The relative contribution of a reduction in fiber number to age-related muscle atrophy may be muscle-dependent.
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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 | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 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) | 0.001 | 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".