Translate and cross-culturally adapt the original English version of the lower extremity functional scale into the Sinhalese version

Objectives: Functional ability is critical for quality of life (QOF), and its evaluation is vital in a clinical context. However, there is a deficiency of a universally recognized grading scale in Sinhala for assessing functional capacity in athletes with lower extremity musculoskeletal conditions. This research aimed to validate the linguistic and cross-cultural adaptation of a translated Sinhala version of the lower extremity functional scale (S-LEFS). Materials and Methods: A two-stage observational study was conducted. The lower extremity functional scale was cross-culturally adapted to Sinhala through independent, double forward, and backward translation. An experienced clinical researcher tested the translated version to establish the linguistic validation of S-LEFS. The finalized version was validated for construct, convergent, and criterion validity. A total of 112 participants, comprising 57 healthy (50.89%) and 55 unhealthy (49.11%) lower limb athletes, completed S-LEFS. Results: S-LEFS demonstrated excellent reliability with a Cronbach’s alpha of 0.952. Exploratory factor analysis revealed good factor loadings (>0.48) for all 20 items, with three components accounting for 70.63% of cumulative variance. Scale got a sensitivity of 87.5% and specificity of 81% at a cutoff point of 67.5. Kaiser-Meyer-Olkin (KMO) value was 0.918 ( P < 0.0001), and Bartlett’s Test of Sphericity was significant ( P < 0.01). No correlation was detected between S-LEFS and World Health Organization QOF-Bref (r = 0.281). Conclusion: S-LEFS is a reliable and valid tool for evaluating lower limb function in athletes.