Reliability of Air Displacement Plethysmography in a Large Sample
Bibliographic record
Abstract
0482 Several studies have examined the validity of air displacement plethysmography (ADP) as a means of measuring body volume (BV) and assessing body density (Db) in humans. However, few studies have been done to assess the reliability of ADP. PURPOSE: To determine the reliability of ADP using the BodPod® in a large sample. METHODS: 980 healthy men and women (30 ± 15y, mean ± SD) completed two body composition assessments separated by 15–30 min. Some of these subjects (n = 348) completed a total of three body composition assessments. All testing was done in accordance with the manufacturer's instructions. RESULTS: Results from 2 tests: There was a significant correlation (r = 0.992, p = 0.001) between Db 1 (1.0463 ± 0.0009 kg/l [mean ± SEM]) and Db 2 (1.0463 ± 0.0009 kg/l). A paired t-test revealed no significant difference between Db 1and 2 (p = 0.935). The coefficient of variation (CV) for Db was 0.15%. Body Mass (BM) 1 and 2 were correlated significantly (r = 0.999, p = 0.001); however, there was a significant (p = 0.001) decrease from BM 1 (75.5095 ± 0.4612 kg) to BM 2 (75.4974 ± 0.4611 kg). BV tended to decrease (p = 0.08) from BV 1 (69.8998 ± 0.4491 l) to BV 2 (69.8840 ± 0.4486 l). Results from 3 tests: There were no significant differences found for Db among the 3 trials (1.0455 ± 0.0015 kg/l, 1.0454 ± 0.0015 kg/l, 1.0457 ± 0.0015 kg/l). The CV for Db was 0.18%. There was a significant decrease with time from BM 1(74.7607 ± 0.7646 kg) to BM 2 (74.7518 ± 0.7645 kg; p = 0.007) and from BM 2 to BM 3 (74.7460 ± 0.7645 kg; p = 0.001). BV decreased (p = 0.043) from BV 1 (69.2607 ± 0.7466 l) to BV 3 (69.2286 ± 0.7450 l). CONCLUSION: ADP using the Bod Pod® appears to assess Db reliably; however, the observed CV suggests that multiple trials are necessary to detect small treatment effects. Performing 3 trials instead of 2 does not appear to increase the reliability. The slight, but significant, reduction in BM seen over a short period of time suggests that the scale is sensitive enough to detect metabolic/evaporative mass loss. Supported by The Joe Weider Foundation
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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 | 0.004 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.003 |
| Science and technology studies | 0.000 | 0.001 |
| 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".