Effect of Creatine Supplementation on Jumping Performance In Highly-Trained Volleyball Players: A Pilot Study
Bibliographic record
Abstract
Vertical jump height is a critical aspect of the blocking and attacking performance of volleyball players. The effect of creatine supplementation (CrS) on jumping performance has not been thoroughly characterized. It has never been previously investigated whether and to which extent CrS affects jumping performance among highly-trained volleyball players. PURPOSE: To report the results of a pilot study which examined the effect of 4 weeks of CrS on 1 RM spike jump and repeated block jump height among players of a University level volleyball team. METHODS: All twelve male athletes (age: 22 ± 1.5 yrs) of the Sherbrooke University volleyball team agreed to participate in this study. Using a randomized and double blind protocol, participants were either supplemented with creatine (4-day loading phase + daily maintenance phase (5g creatine + 30g dextrose/sucrose/day)) or a placebo (dextrose/sucrose only) for 28 days. Participants were familiarized with the blocking and attacking tests. Before and after the supplementation periods, subjects performed a 1 RM spike jump test and completed 10 series of 10 block jumps, with a 3 sec interval between jumps and a recovery interval between series of 2 min. STATISTICS: Conventional and magnitude-based inferential statistics were used. RESULTS: Two participants abandoned the study due to injuries and the results of two others were eliminated as they were ± 3 SD outside the sample mean values. CrS did not significantly alter body mass compared with placebo. Jump height over the 100 block jumps increased by a mean of 1.9% (95% CI: ± 3.7%, 70% possibly beneficial) with CrS compared with placebo. Over the first two block jump series, the effect of CrS was unclear. For series 3 to 6, mean block jump height increased by 2.1% (95% CI: ± 3.6%, 75% possibly beneficial) with CrS compared with placebo. With respect to series 7 to 10, CrS increased block jump height by a mean of 1.7% (95% CI: ± 3.6%, 66% possibly beneficial) compared with placebo. The effect of CrS on 1 RM spike jump height was trivial. CONCLUSIONS: Our results indicate that, in highly-trained volleyball players, CrS is likely to improve VJ performance in situations of fatigue and encourage the conduct of further studies on the topic.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.002 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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".