The effects of Hip Abductor Fatigue on Low Back Pain Development during Prolonged Standing
Bibliographic record
Abstract
The goal of this thesis was to use hip abductor fatigue to perturb those who do and do not develop pain from standing and determine changes in muscular and postural responses. \n\tForty young healthy participants performed two sessions of standing work for two hours each. Participants performed a side-lying leg raising exercise to fatigue prior to one of the standing sessions, the other session acted as a control. Surface electromyography (EMG) of six muscles bilaterally, motion capture of the trunk and lower limbs, and force plate data under each foot were measured continuously during each standing session. Self-reported pain and isometric hip abductor strength were assessed at discrete time points using 100 mm visual analog scales and uni-axial force transducers respectively. Participants were classified as pain developers (PDs) or non-pain developers (NPDs) based on a 10 mm threshold in low back pain scores during the control session. \n\tPDs (16/40) reported decreases in low back pain while standing during the fatigue session (10.9 ± 11.7 mm reduction) while NPDs reported minimal changes in pain with fatigue (1.5 ± 3.9 mm increase). Decreases in trunk (1033.9 ± 528.6 %MVIC reduction in first hour) and gluteal cocontraction indices (398.8 ± 792.4 %MVIC decrease in the 15 minute block) and increases in the number of anterior-posterior centre of pressure fidgets (13.5 ± 25.4 increase in the 30 minute block) were observed in the first hour of the fatigue session in PDs. Female PDs had more posterior pelvic tilt with fatigue (3.9 ± 9.2° more posterior with fatigue from 30 to 90 minutes), distinguishing them from male PDs (7.0 ± 11.3° more anterior with fatigue from 15 to 120 minutes). Both pain groups had similar EMG frequency shifts and strength lost due to fatigue. NPDs had longer times to fatigue than PDs (NPDs: 20.1 ± 11.2 minutes; PDs: 18.7 ± 9.3 minutes; p = 0.0106). \n\tThis study provides evidence that the hip abductor musculature is likely one causative factor in the low back pain developed from standing. Also, PDs had fatiguing characteristics of persons suffering from chronic low back pain, only without any pain present.
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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".