REPRODUCIBILITY AND VALIDITY OF ULTRASOUND MEASUREMENTS OF MUSCLE THICKNESS
Bibliographic record
Abstract
PURPOSE The purpose of this study was to determine the reproducibility and validity of muscle thickness measurements made at the vastus lateralis by B-mode ultrasound (Aloka SSD-500). METHODS Reproducibility was determined by the coefficient of variation of duplicate measurements on nine subjects (5 males, 4 females, age 20–39y) one week apart. Validity was determined by assessing the ability of muscle thickness measurements to predict maximal isokinetic torque output during knee extension in a group of 39 subjects (20 males, 19 females, age 18–31y). Muscle thickness (distance from subcutaneous fat to the femur) was measured with a 5 MHz ultrasound probe at three points (distal, mid, and proximal) separated by 6 cm, with the mid-point located two thirds the distance from the greater trochanter to the lateral epicondyle and 3 cm lateral to the midline of the anterior thigh. Torque output was measured as the best of three maximal knee extensions at a velocity of 1.04 radians per second on a Biodex isokinetic dynamometer. RESULTS The coefficients of variation for repeated measurements were 1.1%, 1.5%, and 3.0% for muscle thickness at distal, mid, and proximal sites, respectively, on the vastus lateralis. Muscle thickness (averaged over the three sites) correlated significantly with maximal isokinetic knee extension torque (r=0.47; p = 0.003). CONCLUSION Muscle thickness of the vastus lateralis, as determined by ultrasound, has good reproducibility and is predictive of knee extension maximal torque.
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How this classification was reachedexpand
Direct model labels (unvalidated)
Per-model category and study-design labels from the labeling rounds. They are machine output, unvalidated, and the disagreement between models ships as data. No study design here is MEDLINE-validated yet.
| Model arm | Categories | Study design | Confidence |
|---|---|---|---|
| gemma | Metaresearch Domain: Methods · Genre: Empirical About the Canadian research system: no · About a Canadian topic: no | Observational | low |
| gpt | Metaresearch Domain: Methods · Genre: Empirical About the Canadian research system: no · About a Canadian topic: no | Observational | high |
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 | 0.013 | 0.044 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 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, unvalidatedLabeled directly by 2 models reading the full record.
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".