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Faculty Advisor(s)

Philip A. Anloague, PT, DHSc


Background/Purpose: Lower extremity injuries occur at an amplified rate in professional basketball. Evidence suggests that knee frontal plane valgus may be associated with risk of injury. The Landing Error Scoring System includes the assessment of maximum knee valgus during a countermovement jump. The investigation of interactions among linear and non-linear factors may help the understanding of the interdependence of various measures and poor performance on the knee valgus displacement (KVD) component of the LESS in professional basketball players. The purpose of this study was to investigate predictors of knee valgus displacement on the LESS. We hypothesize that a positive finding on the knee valgus displacement component of the LESS will be predicted by select clinical measures.

Methods: 47 professional basketball players participated. Measurements were completed as part of preseason mobility screening prior to the 2015-16 and 2016-17 NBA seasons. Classification and Regression Tree Analysis (CART) were used to investigate linear and non-linear interactions among predictors and their influence on KVD in players who performed the LESS test.

Results: Of the 47 players included in this study, 16 players did not test positive for KVD on the LESS test and 31 did. Pruning resulted in 4 splits (r2=0.507) demonstrating that KVD was predicted by total hip rotation range of motion, dominant leg hip external rotation, and standing arch height index measure. Predictive modeling, classified 18 of the 31 players with KVD and 8 of the 16 players who tested negative for KVD. The area under the ROC curve was .9183, suggesting that classification of players using this model was not random.

Conclusion: KVD and performance on the LESS has been linked with injury. CART analysis captured linear and non-linear interactions between clinical measures suggesting that lower extremity biomechanical factors may be associated with predicting KVD during performance on the LESS.

Clinical Relevance: KVD and the LESS test has been shown to be predictive of injury. Identifying which clinical measures may be linked with poor performance on this test may aide clinicians in determining appropriate interventions that may be associated with improved scores and minimize risk of injury.

Publication Date



Physical Therapy | Rehabilitation and Therapy



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