Effects of leg contrast strength training on sprint, agility and repeated change of direction performance in male soccer players
Bibliographic record
Abstract
BACKGROUND: Contrast training is a popular technique among individuals who are involved in dynamic sports, having as its goal an increase in dynamic muscular performance. It is characterized by the use of high and low loads in the same strength training session. The present investigation aimed to determine the effects of adding 8 weeks of contrast strength training (CSTP) to regular soccer practice in U-17 male soccer players during the competitive season. We hypothesized that CSTP would enhance their performance. METHODS: Subjects were divided randomly between a control group (CG, N.=12) and a contrast strength group (CSG, N.=19). The 2 groups trained together; controls followed the regular soccer program, which was replaced by a contrast strength training program for the experimental group. Performance was assessed before and after training, using 10 measures: 5-10-, 20- 30-, and 40-m sprints, a 4x5 m sprint (S4x5), a 9-3-6-3-9 m sprint with 180° turns (S180), a 9-3-6-3-9 m sprint with backward and forward running (SBF), a Repeated-Shuttle-Sprint Ability Test (RSSA), and a Repeated Change of Direction Test (RCOD). RESULTS: CSG showed gains relative to controls in 5-m (P<0.000), 10-m (P<0.001), 20-m (P<0.001), 30-m (P<0.05) and 40-m (P<0.05) sprints. There were also significant gains in S180°, SBF, and S4 x 5 agility tests (P<0.01), and all RCOD parameters (P<0.05) except RCOD-FI (P=0.055) but no significant change in any RSSA parameters. CONCLUSIONS: We conclude that biweekly contrast strength training can be commended to U-17 male soccer players as a means of improving many important components of athletic performance relative to standard in-season training.
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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 | 0.000 | 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 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".