Item Specific Reliability Analyses Of The Landing Error Scoring System (LESS)

Abstract

The Landing Error Scoring System (LESS) has been developed as a tool to identify potentially faulty movement patterns and poor technique during a jump-landing task. The ability to identify individuals who display faulty movement patterns and poor technique may help in identifying those individuals at risk for sustaining ACL injury. The reliability of the LESS must be established in order to utilize the LESS as a tool to identify faulty movement patterns and poor technique. Purpose To determine the item specific intra-rater and inter-rater reliability of the LESS. Methods Twenty participants (males=10, females=10) took part in this study. Participants performed a jump-landing task by jumping from a 30-cm high box that was set a horizontal distance equal to 50% of their body height away from the landing area. Following the initial landing the participants immediately jumped upward for maximal vertical height. Video cameras recorded the jump-landing task from frontal and saggital plane views. Two different investigators reviewed the previously recorded video images using the LESS and identified errors during jump-landing task. One of the investigators re-scored the trials on a second occasion. The item specific inter-rater reliability was assessed by calculating the percent agreement between the two investigators scores for each LESS item. The item specific intra-rater reliability was assessed by calculating the percent agreement between days for each LESS item as scored by one of the investigators. We also examined the inter-rater and intra-rater reliability of the total LESS scores (sum of all errors committed) using ICC(2, k). Results The item specific intra-rater reliability was excellent for each item (percent agreement range = 90%–100%) and total LESS score (ICC=.98, SEM=.30). The inter-rater reliability ranged from good to excellent for each item (percent agreement range = 75%–100%) and was excellent for total LESS score (ICC=0.83, SEM=.95). Conclusion The LESS can be used as a reliable tool to identify faulty movement patterns and poor technique during a jump-landing task both within and between raters. Future research is needed to determine the validity of the LESS for predicting individuals who are at risk for an ACL injury. (Funded by the American Orthopaedic Society for Sports Medicine)