BACKGROUND Several biomechanical deficits have been shown to increase non-contact knee injury risk of the anterior cruciate ligament (ACL). The Landing Error Scoring System (LESS) is a clinical assessment tool that has been successfully used to predict the individuals that are at a high risk for injury and evaluate changes in landing technique after participation in a neuromuscular preventive training program. The LESS-RT is a shortened version of the LESS and is a method to score landing technique without the use of video. The current study proposes a new tool for the evaluation of landing technique and ACL injury risk that blends the LESS and LESS-RT protocols but emphasizes the movement features that contribute to high knee valgus moments including movement asymmetry. The LESS-RMC (Rocky Mountain Consortium) consists of evaluating 11 comprehensive landing errors that are related to ACL injury risk. Consolidating questions pertaining to the opposite ends of joint motion such as “toe in” and “toe out” into “maximum foot rotation position” and adding a global asymmetry score were performed to reduce the time demands for evaluation yet capture the salient factors of the LESS; whereas the penalty for knee valgus severity was pulled from the LESS-RT but implemented for both knees in the new LESS-RMC to ultimately stratify knee injury risk during the jump landing task. The purpose of this study was to determine the reliability of the new LESS-RMC assessment tool. METHODS Thirty-seven, elite female soccer athletes (13.2 +/- 0.4 y) performed three drop-jumps from a height of 30 cm. Front and side views of the landing were recorded with digital video cameras. Movement quality was rated by 4 researchers evaluating 17 components of the landing with the LESS and a modified, 11 component version of the LESS (LESS-RMC). The 4 raters were novel to the evaluation of both scoring systems. Each rater was trained how to score each test and was instructed to evaluate the landing trials from the first 10 participants. After a group video review and discussion, the raters repeated the scoring procedures for the same 10 participants 48 hours after the original review. After another 48 hours, the raters evaluated the landing trials for all 37 participants (111 trials). Inter-rater reliability of the LESS and LESS-RMC were determined using the ICC (3,1) equations and the output from a two-way ANOVA (SPSS, version 25). RESULTS The mean LESS score was 6.45 +/- 0.55 (rater 1, 6.42; rater 2, 7.15; rater 3, 5.79; rater 4, 6.45). The ICC agreement between raters of scoring the LESS was .389 whereas the ICC agreement for the mean of the four raters was .718. The ICC for scoring consistency was .382 and Cronbach’s a was .735. The mean LESS-RMC score was 6.19 +/- 0.74 (rater 1, 5.65; rater 2, 6.99; rater 3, 5.48; rater 4, 6.64). The ICC agreement of scoring the LESS-RMC was .585 whereas the ICC agreement for the mean of the four raters was .849. The ICC for scoring consistency was .574 and Cronbach’s a was .884. CONCLUSION On average, the raters scored the LESS and the LESS-RMC with moderate reliability across the group of athletes. The LESS-RMC was scored with greater reliability than the LESS for this group of relatively novice raters. This is likely due to the simplification of the overall protocol in terms of quantity of questions, the ability of a novel rater to understand scenarios which elicit specific scores and the clear separation of body segments (e.g. hip and trunk flexion). In conjunction with this, it was reported by the raters that LESS-RMC was less redundant and more effective at assessing crucial aspects of a jump landing pattern. Overall, LESS RMC was objectively and subjectively more reliable and easier to use than the LESS for the four raters involved in this study. It is concluded that the LESS-RMC is a quick, easy and reliable clinical assessment tool that may be used to stratify individuals who may be at risk for ACL injury.
Reliability of the Landing Error Scoring System-Real Time, a Clinical Assessment Tool of Jump-Landing Biomechanics
