Human <i>COL5A1</i> polymorphisms and quadriceps muscle–tendon mechanical stiffness <i>in vivo</i>
Bibliographic record
Abstract
NEW FINDINGS: What is the central question of the study? Do COL5A1 gene variants, previously reported to have diminished transcript stability, manifest in physiological phenotypes of quadriceps muscle-tendon contractile properties and mechanical stiffness in humans? What is the main finding and its importance? COL5A1 gene variants influence mechanical stiffness, not seeming to affect low-level contractile properties in humans. Functional differences in COL5A1 manifest during moderate- to high-level contractions. Polymorphisms of the collagen type V alpha 1 chain (COL5A1) gene are purported to influence mechanical properties of collagenous tissues. Our purpose was to assess musculotendinous contractile properties of the quadriceps in relationship to the genetic influence of mechanical stiffness. Eighty recreationally active males (aged 19-31 years) were assessed for the presence of three genetic polymorphisms associated with COL5A1 mRNA stability (rs4919510, rs1536482 and rs12722). Genotypes were determined using real-time PCR. Stiffness and contractile properties of the knee musculotendinous complex were assessed by maximal isometric voluntary contractions, ramp isometric voluntary contractions, electrically stimulated contractile events and ultrasonography. All genotype groups were able to activate their knee extensors fully (>97%) as assessed by the interpolated twitch technique and presented no differences in muscle-tendon contractile properties at low submaximal contraction intensities. For the quadriceps muscle-tendon at moderate ramp contractions of 50 and 60% maximal voluntary contraction, the rs12722 CT and TT genotypes had ∼30% greater mean stiffness. The rs1536482 AG and GG genotypes showed a similar trend, but did not achieve statistical significance. Variants of the COL5A1 gene seem to influence quadriceps muscle-tendon stiffness but do not affect low-level contractile properties.
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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 | 0.000 | 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) | 0.001 | 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 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".