Reliability, Validity, and Predictive Value of the Landing Error Scoring System in Soccer Players: A Systematic Review.

CONTEXT: Lower-limb injuries are common in soccer. The landing error scoring system (LESS) is used widely for field-based movement screening, yet its psychometric properties and prognostic value in soccer populations remain uncertain. OBJECTIVE: To synthesize evidence on the reliability, validity, and prognostic utility of the LESS among soccer participants. DATA SOURCES: PubMed, Web of Science, Cochrane Library, CNKI, and Wanfang were searched from inception to August 2025. STUDY SELECTION: Studies were included if they involved soccer participants and reported LESS-related reliability, validity, or prognostic outcomes. Modified versions of the LESS were included only when their scoring framework was clearly described and broadly comparable with the original tool. STUDY DESIGN: Systematic review with exploratory meta-analysis. LEVEL OF EVIDENCE: Level 2 to 4. DATA EXTRACTION: Two reviewers independently screened studies, extracted data, and assessed methodological quality using a modified Newcastle-Ottawa Scale. Reliability and validity outcomes, including intraclass correlation coefficients (ICCs) and agreement with 3-dimensional (3-D) motion analysis, were summarized descriptively. Prognostic metrics, including odds ratios (ORs) and area under the curve values, were extracted when available. When ≥2 comparable prospective cohorts were available, an exploratory random-effects meta-analysis was performed. RESULTS: A total of 10 studies met the inclusion criteria. In soccer settings, the LESS demonstrated excellent intra-rater reliability (ICC ≈ 0.90-0.95) and good inter-rater reliability (ICC ≈ 0.84-0.95), with item-dependent convergent validity versus 3-D kinematics. Evidence for prognostic utility was inconsistent across cohorts. Exploratory pooling of 2 comparable prospective studies showed that higher preseason LESS scores were associated with greater odds of subsequent lower-limb injury (pooled OR, 9.31; 95% CI, 3.11-27.91; I² = 0%). However, this pooled estimate should be interpreted cautiously because it was based on only 2 studies with variable injury definitions. CONCLUSION: The LESS is reliable and shows acceptable construct validity in soccer participants, but evidence for its prognostic utility remains inconsistent. It should not be interpreted as a stand-alone predictor of injury risk. Clinically, the LESS may serve as a low-cost, field-based assessment of landing movement quality within a broader multifactorial screening framework.