Planar Accelerometry As A Measure Of Subject Compliance With Unilateral Lower Limb Suspension
Bibliographic record
Abstract
Human unilateral lower limb suspension (ULLS) is a commonly used model to study the effects of muscle disuse. Studies typically require subjects to walk on crutches with one elevated shoe for a prolonged period of time. Ensuring subject compliance is critical to the integrity of the study. Previous investigators have used only gross indicators of compliance, such as skin temperature and leg circumference. PURPOSE The purpose of this study was to validate the use of an accelerometer during normal and ULLS ambulation. METHODS Ten subjects (26.4±3.6 years; 170.9±6.9cm; 68.0±9.6kg) wore a biaxial accelerometer (AMP 331, Dynastream Innovations, Inc. Alberta, Canada) around their left ankle and participated in normal and ULLS ambulation at a self-selected slow, medium and fast pace. Additionally, subjects completed a small obstacle course to imitate daily household activity during ULLS ambulation. All subjects were videotaped and the number of steps taken and their speed during the conditions was recorded. Mean peak axial acceleration (MPAA), the speed of the leg swing, was calculated by the accelerometer during each walking condition. A step during ULLS ambulation was considered a false positive if the MPAA during ULLS was greater than or equal to the minimum MPAA recorded during normal walking. RESULTS Overall sensitivity (the ability to detect steps, when steps are taken during normal walking) and specificity (the ability to not detect steps when steps are not taken during ULLS) of the accelerometer were 97% and 96% respectively. The overall sensitivity among the subjects ranged from 96–100% and the specificity ranged from 83–100%. The specificity of the obstacle course was 100%. CONCLUSION The use of the AMP 331 accelerometer during ULLS ambulation is an effective tool for measuring subject compliance as the sensitivity and specificity of the device are high. Since some steps were actually detected by the accelerometer on the unweighted limb during ULLS, the errors slightly overestimated the number of steps taken during ULLS. ACKNOWLEDGEMENTS Supported by the following grants to BCC: NASA GSRP Grant (NGT5-50446), NASA Space Physiology Research Grant through the ACSM Foundation
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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 | 0.001 | 0.003 |
| 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) | 0.001 | 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".