Impact of Early Specialization on Ice Hockey Goaltender Hip Kinematics
Bibliographic record
Abstract
The purpose of this cross-sectional study was to compare hip kinematics between early specialized (ES) and not early specialized (NES) ice hockey goaltenders.This study included 13 ES and 13 NES goaltenders.Kinematics were quantified during common goaltender tasks (i.e., butterfly drops, power and butterfly slides) on a custom slide board using Theia3D markerless technology.The maximum and minimum hip flexion, adduction, and internal rotation angles were determined.The concurrent hip angles in the two other planes at these maximum and minimum positions were also extracted (e.g., adduction and internal rotation at maximum flexion).For discrete data, groups were compared using independent t-tests or Mann-Whitney U tests (α = 0.05), dependent on normality.Statistical parametric mapping was used to compare the groups' hip angles over time.The ES goaltenders moved with increased hip internal rotation and abduction at lower hip flexion angles but with less internal rotation and abduction at higher flexion.Neither of the groups reached the expected extreme ranges of flexion, adduction, or internal rotation typically associated with the mechanical bony impingement of FAIS.The ES goaltenders may minimize large magnitudes of combined flexion and internal rotation or abduction as a pain avoidance mechanism in hips with FAIS or labral tears, or they developed advantageous hip control strategies to avoid abnormal hip contact mechanics that contribute to the development of these pathologies.This study also suggests that hip joint loading throughout internal rotation and abduction may be influential in goaltenders' increased risk of intra-articular hip injuries. KEY POINTSFindings Early specialized goaltenders minimized the combination of flexion and internal rotation or abduction during several tasks.Early and not early specialized goaltenders achieved ranges of motion that would correspond with increased labral strain but not the mechanical bony impingement associated with FAIS.Implications Loading of hip joint structures at sub-maximal ranges of motion is an important consideration for future research on intra-articular hip injuries.When recommending to avoid early sports specialization based on injury risk, consideration of other sports participation should be made to avoid overloading specific structures.Caution This cross-sectional design does not establish a causal relationship between early specialization, kinematics, and hip injuries.
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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 | 0.000 |
| 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".