Document Type


Publication/Presentation Date

December 2020


PURPOSE/HYPOTHESIS:Anterior cruciate ligament (ACL) injuries are very common in athletes. Factors associated with increased risk of ACL injury include decreased hip and knee flexion, increased knee valgus, and increased GRF, among others. Screening tools are available that attempt to identify movement dysfunction that may increase the risk of injury. One measure that has been proven to be valid and reliable is the LESS. The LESS-RT requires the same validity and reliability assessment as it is more clinically useful from an efficiency perspective. The purpose of this study was to investigate the ability of the LESS-RT to accurately detect abnormal biomechanics during a jump-landing task to determine its validity by comparing investigator visual scoring with the gold standard of 3-D motion analysis of the lower extremity. Authors hypothesize that the LESS-RT will identify subjects with potentially high risk jump landing biomechanics. And more specifically, poor LESS scores will be associated with decreased hip and knee flexion angles, increased knee valgus angle and moment, increased hip and tibial rotation, and increased ground reaction forces. SUBJECTS: 50 MATERIALS/METHODS:Fifty subjects, including 24 males (26.5 ±3.3yrs, 70.9 ±2.1in, 181.8 ±27.1lbs) and 26 females (23.8 ±0.4yrs, 65.6 ±2.6in, 154.6 ±32.4lbs) participated in this study. Subjects performed 4 trials of a jump-landing task from a 30 cm box with simultaneous data collection of 3D hip and knee motion and LESS-RT visual scoring by 3 raters. Kinematic and kinetic measures from 3D motion analysis and forceplate data were compared across LESS score quartiles using a series of 1-way ANOVAs; LESS quartiles were compared by sex using a chi-square. Interrater reliability was also computed using ICC2,k and SEM calculations. RESULTS:Subjects with high/poor LESS-RT scores demonstrated significantly different kinematics and kinetics compared to those with low/excellent LESS-RT scores for bilateral hip and knee flexion displacement and bilateral peak hip and knee flexion angles; peak right knee valgus moment; right peak hip adduction and internal rotation moments; and bilateral vertical GRF (p<.05). Women had higher/worse LESS-RT scores than men (5.5 vs. 3.4). Interrater reliability of the LESS-RT was good at 0.85 and SEM at .42. CONCLUSIONS: The LESS-RT demonstrates preliminary results that support it as a potentially valid tool for identifying high-risk movement patterns during a jump-landing task. Reliability is favorable and similar to what was previously demonstrated in a larger study. A larger sample size is required to confirm these results. CLINICAL RELEVANCE: Given clinical time constraints, a quick and easy assessment that provides an accurate and valid reflection of lower extremity movement patterns that may result in knee injury provides a useful tool for clinicians to utilize as a basis for exercise programming.