Kinematic and Kinetic Predictors of Y-Balance Test Performance.
Samuel Nelson, Charles S Wilson, James Becker
PMID 33842033WHAT IT FOUND
Y-balance reach in 31 trained runners was mainly predicted by knee flexion for anterior reach and hip flexion for posterior reaches.
Knee and hip moments also predicted reach. A short reach did not point to one cause.
Key findings
01Knee flexion and torso contralateral rotation explained 45.8% of the variation in anterior reach distance.
02Hip flexion, ankle dorsiflexion and ankle external rotation explained 76.9% of the variation in posteromedial reach distance.
03Knee extensor moment and hip abductor moment explained 46.1% of the variation in anterior reach distance.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
The sample was small and narrow: 31 healthy, moderate to highly trained runners, so it may not apply to patients, sedentary people, or athletes in multi-direction sports. All testing was done barefoot on the dominant limb in a laboratory, and the authors note footwear and the measurement method may change performance or reach values. Males and females were analyzed together; sex may affect reach distances or the movement strategies used to achieve them. This was a cross-sectional predictor study, not a treatment trial or injury follow-up, so it cannot show that changing knee, hip, ankle or trunk variables causes better balance or fewer injuries.
Declared interests
The authors disclosed no conflicts of interest. The study was funded by the Ellen Kreighbaum Movement Science Lab Endowment at Montana State University.
The easy way to misread this
Do not read a short Y-balance reach as proof of a specific strength deficit or injury risk. This was a small cross-sectional lab study of 31 healthy trained runners. The variables explained reach distance but were not tested as causes, and the study did not follow participants for injury.