Intersession, Intrarater, and Interrater Reliability of the Single- and Double-Leg Landing Error Scoring Systems in...

The double-leg Landing Error Scoring System (LESS) identifies noncontact ACL injury risk. However, its intersession reliability has been examined in only one study. As such injuries often occur during single-leg landings, research on the single-leg LESS (SLESS) in field settings remains lacking. Therefore, our study investigated the intersession, intrarater, and interrater reliability of single- and double-leg jump-landing tasks using SLESS and LESS.

Thirty-five team-sports players (age: 26.4 [6.7] years, n = 28 males and 7 females) performed 3 jump-landing variations (single-leg dominant and nondominant and double leg) across 3 sessions. We conducted sessions 1 and 2 on the same day, with session 3 one week later. Three assessors rated video footage to determine SLESS and LESS total scores. Reliability was assessed using the intraclass correlation coefficient (ICC), standard error of measurement, and coefficient of variation (CV) with 95% CIs.

Intersession reliability for the SLESS and LESS scores showed good to excellent ICCs (dominant leg: .89, nondominant leg: .91, double leg: .79) with moderate CVs (dominant leg: 6.5%, nondominant leg: 6.6%, double leg: 7.9%). Intrarater reliability for the SLESS and LESS scores also demonstrated good to excellent ICCs (dominant leg: .94, nondominant leg: 0.92, double leg: .88) with moderate CVs (dominant leg: 5.0%, nondominant leg: 6.0%, double leg: 5.6%). Interrater reliability for the SLESS and LESS scores exhibited good ICCs (dominant leg: .82, nondominant leg: .83, double leg: .79) but poor CVs (dominant leg: 10.5%, nondominant leg: 11.5%, double leg: 11.5%). Single-leg LESS and LESS scores exhibited small standard error of measurement values between 1.05 and 1.11 for all reliability measures.

The SLESS and LESS are reliable field-based tools for assessing jump-landing tasks among team-sports players, facilitating confidence in sports and exercise science research.