Intra-Rater and Inter-Rater Reliability of Muscle Length Test for Extensor Digitorum Longus

Abstract

Background A short extensor digitorum longus (EDL) is associated with limited ankle dorsiflexion, toe deformities (such as hammer toe and claw toe), and diabetic plantar ulcers. Therefore, measurement of EDL is important for the evaluation of patients with foot dysfunction. Purpose The aim of this study was to evaluate the intra- and inter-rater reliability of the muscle length test for EDL. Study design Repeated measures for intra- and inter-test reliability. Methods Thirty participants were recruited. Two physical therapists evaluated EDL length based on the difference in passive ankle plantar flexion angle between relaxed and flexed toe positions. Each examiner measured it in each participant three times. The intraclass correlation coefficient was used to assess the intra- and inter-rater reliability of the muscle length test for EDL. Results The intra- and inter-rater reliability values were 0.83 and 0.75, respectively. The standard error of measurement was 1.93° and the minimum detectable change was 5.35°. Conclusions The muscle length test is a reliable method for measuring EDL length in clinical practice.