Association of plasma 25-hydroxyvitamin D with physical performance in physically active children
Bibliographic record
Abstract
Vitamin D is thought to regulate skeletal muscle function and boost physical performance. The aim of this study was to assess the relationship between vitamin D and physical performance in physically active children. This cross-sectional study included 125 children who practice football as a leisure activity. Plasma 25-hydroxyvitamin D (25-OHD) was assessed using a chemiluminescence immunoassay method. Vitamin D inadequacy was defined as 25-OHD < 20 ng/mL. Physical performance testing included measurements of muscle strength (maximal isometric contraction), jumping ability (vertical jump, standing broad jump, triple hop test), linear sprint (10 m and 20 m), and agility (9 × 4-m shuttle run). Plasma 25-OHD concentrations were positively correlated with muscle strength (r = 0.539; p < 0.001), vertical jump (r = 0.528; p < 0.001), and standing broad jump (r = 0.492; p < 0.001) but inversely correlated with sprint performance (r = -0.539; p < 0.001). In multivariate analysis models, plasma 25-OHD concentrations were associated with each physical performance parameter independently of age, maturity status, body mass index, fat mass, and protein and calcium intakes. In conclusion, a low plasma 25-OHD level was associated with decreased muscle strength, agility, and jumping and sprinting abilities in physically active children. Vitamin D inadequacy may limit exercise performance. Further research should verify whether correction of vitamin D deficiency enhances physical performance.
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| 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".