Electromyographic activity imbalances between contralateral back muscles: An assessment of measurement properties
Bibliographic record
Abstract
Electromyographic (EMG) contralateral imbalances of back muscles are often interpreted as an aberrant back muscle pattern related to back pain. This study assessed different measurement properties (influence of the control of asymmetric efforts and of the force level, reliability, and sensitivity to low back status) of EMG imbalance parameters. Healthy controls (n = 34) and chronic low back pain subjects (n = 55) stood in a dynamometer measuring the principal (extension) and coupled (lateral bending, axial rotation) L5/S1 moments during isometric trunk extension efforts. The results showed that back pain subjects did not produce higher coupled moments than controls. Providing feedback of the axial rotation moment to correct asymmetric efforts during the task did not reduce EMG contralateral imbalances, except for some extreme cases. Normalized EMG imbalance parameters remain relatively constant between 40% and 80% of the maximal voluntary contraction. The reliability of EMG imbalance parameters was moderate, at best. Finally, neither low back status nor pain location had an effect on EMG contralateral imbalances. We conclude that the clinical relevance of EMG contralateral imbalances of back muscles remains to be established.
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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 | 0.009 | 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".