The Cervical Flexion-Relaxation Ratio
Bibliographic record
Abstract
STUDY DESIGN: Reliability study. OBJECTIVE: To determine the reproducibility of the cervical flexion-relaxation ratio (FRR) measured 4 weeks apart in a group of chronic neck pain patients and healthy control group and to compare the FRR between the 2 groups. SUMMARY OF BACKGROUND DATA: The cervical FRR measures the ability of the neck extensor muscles to relax during forward flexion, similar to the lumbar FRR. Its reliability and ability to discriminate neck pain patients from controls has not been investigated. METHODS: Fourteen participants with chronic neck pain and a control group of 14 individuals with no neck pain were recruited via advertisement and word of mouth. The cervical FRR was determined at baseline and 4 weeks later using standardized electromyographic data collection and analysis procedures. RESULTS: The mean FRR value for the combined left and right side data for the neck pain groups was 1.93 ± 0.8, and 1.73 ± 0.61 at 4-week follow-up. The intraclass correlation coefficient (ICC) was 0.83 (95% CI = 0.67-0.92). Three participants in the control group developed neck pain in the 4 weeks and their data were not included in the reliability calculation. For the control group, the combined (left and right side) mean FRR value was 4.09 ± 1.58 at baseline and 4.27 ± 1.71 on retest 4 weeks later. The ICC (intraclass r) was 0.89 (95% confidence interval = 0.76-0.95). The overall ICC for the combined groups was 0.92 (95% confidence interval = 0.86-0.95). An independent 2 group t test revealed a significant difference in the baseline FRR data between the control group and the neck pain group (P < 0.001). CONCLUSION: The cervical extensor muscles exhibit a consistent flexion-relaxation phenomenon in healthy control subjects and the measurement is highly reproducible when measured 4 weeks apart in both controls and chronic neck pain patients. The FRR in neck pain patients is significantly higher than in control subjects suggesting that this measure may be a useful marker of altered neuromuscular function.
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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 | 0.005 | 0.011 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".