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Updated: Aug 5, 2026
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Video Movement Analysis Using Smartphones (ViMAS): A Pilot Study
Published on: March 14, 2017
Does Medial Knee Position Reflect Dynamic Knee Valgus? Comparing Kinematic Timing and Magnitude During a Three-Task
Ashley Erdman1, Ben Randoing1, James J McGinley1
1Center for Excellence in Sports Medicine, Scottish Rite for Children, Frisco, TX, USA.
International Journal of Sports Physical Therapy
|August 4, 2026
Summary
Two-dimensional (2D) movement screenings for youth athletes show that medial knee collapse timing does not always align with maximum knee abduction in 3D analysis. However, 2D assessments remain a practical tool for evaluating lower extremity movement patterns.
Area of Science:
- Biomechanics of youth athletes
- Injury prevention strategies
- Knee kinematics analysis
Background:
- Movement screenings are used to reduce knee injuries in young athletes.
- The effectiveness of 2D risk assessments in capturing multi-planar dynamic knee valgus contributors is not well understood.
Purpose of the Study:
- To compare medial knee collapse with multi-planar components of dynamic knee valgus.
- To evaluate the timing and magnitude of knee abduction and medial knee position.
Main Methods:
- Adolescent female volleyball players underwent a 3D motion capture analysis during single-leg squat, single-leg drop landing, and double-leg vertical jump tasks.
- Key metrics extracted included the timing and magnitude of most medial knee position (MMK) and maximum knee abduction angle (MKA).
- Statistical comparison of kinematic variables at MMK and MKA was performed using Wilcoxon signed-rank tests.
Main Results:
- Most medial knee position generally preceded maximum knee abduction in drop landing and vertical jump tasks.
- Specific tasks showed variations in pelvic rise, hip adduction, and hip external rotation at MMK compared to MKA.
- Tibial rotation was consistently more external when the knee was at its most medial position across all tasks.
Conclusions:
- Two-dimensional medial knee collapse measurements do not perfectly correlate with 3D dynamic knee valgus components.
- Despite discrepancies, 2D peak knee medialization is a clinically accessible method for assessing lower extremity movement when 3D analysis is unavailable.
