Comparison of Pelvis and Trunk Kinematics Between Youth and Collegiate Windmill Softball Pitchers
Bibliographic record
Abstract
Background: The windmill softball pitch is a dynamic sporting movement that places softball pitchers at high risk of injury. Unlike baseball, there is limited research into the mechanical differences between softball pitchers of varying skill levels. Purpose/Hypothesis: The purpose of this study was to compare pelvis and trunk kinematics between youth and collegiate softball pitchers. It was hypothesized that there would be significant differences in pelvis and trunk kinematics between these 2 groups. Study Design: Descriptive laboratory study. Methods: The pelvic and trunk kinematics of 90 softball pitchers were collected during full-effort pitching using a 3-dimensional motion capture system. Participants were grouped based on their age at the time of data collection (35 youth [mean age, 11 ± 1 years]; 55 collegiate [mean age, 20 ± 2 years]). We compared between-group differences in pelvic posterior tilt, lateral tilt, axial rotation, and axial rotation velocity as well as trunk extension, lateral flexion, axial rotation, and axial rotation velocity during the pitching phase between start of pitch and ball release (BR) using 1-dimensional statistical parametric mapping. Statistical significance was determined using Holmes-Šidák stepdown correction–adjusted P values ( P ′). Results: Compared with youth pitchers, collegiate pitchers exhibited a more posteriorly tilted pelvis from the moment of start of pitch until 94% of the way between start of pitch and BR ( P ′ = .002) and a more laterally flexed trunk toward the glove side from the moment of start of pitch until 71% of the way between start of pitch and BR ( P ′ = .010). Conclusion: Collegiate pitchers displayed a more posteriorly tilted pelvis and more laterally flexed trunk toward the glove side during the windmill pitching motion when compared with youth pitchers. Clinical Relevance: These findings add to the growing body of softball research and help elucidate mechanical differences between youth and collegiate softball pitchers.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".