The Functional Movement Screen: A Reliability Study

STUDY DESIGN: Reliability study. OBJECTIVES: To determine intrarater test-retest and interrater reliability of the Functional Movement Screen (FMS) among novice raters. BACKGROUND: The FMS is used by various examiners to assess movement and predict time-loss injuries in diverse populations (eg, youth to professional athletes, firefighters, military service members) of active participants. Unfortunately, critical analysis of the reliability of the FMS is currently limited to 1 sample of active college-age participants. METHODS: Sixty-four active-duty service members (mean +/- SD age, 25.2 +/- 3.8 years; body mass index, 25.1 +/- 3.1 kg/m(2)) without a history of injury were enrolled. Participants completed the 7 component tests of the FMS in a counterbalanced order. Each component test was scored on an ordinal scale (0 to 3 points), resulting in a composite score ranging from 0 to 21 points. Intrarater test-retest reliability was assessed between baseline scores and those obtained with repeated testing performed 48 to 72 hours later. Interrater reliability was based on the assessment from 2 raters, selected from a pool of 8 novice raters, who assessed the same movements on day 2 simultaneously. Descriptive statistics, weighted kappa (kappa(w)), and percent agreement were calculated on component scores. Intraclass correlation coefficients (ICCs), standard error of the measurement, minimal detectable change (MDC95), and associated 95% confidence intervals (CIs) were calculated on composite scores. RESULTS: The average +/- SD score on the FMS was 15.7 +/- 0.2 points, with 15.6% (n = 10) of the participants scoring less than or equal to 14 points, the recommended cutoff for predicting time-loss injuries. The intrarater test-retest and interrater reliability of the FMS composite score resulted in an ICC3.1 of 0.76(95% CI: 0.63, 0.85) and an ICC2.1 of 0.74 (95% CI: 0.60, 0.83), respectively. The standard error of the measurement of the composite test was within 1 point, and the MDC95 values were 2.1 and 2.5 points on the 21-point scale for interrater and intrarater reliability, respectively. The interrater agreement of the component scores ranged from moderate to excellent (kappa(w) = 0.45-0.82). CONCLUSION: Among novice raters, the FMS composite score demonstrated moderate to good interrater and intrarater reliability, with acceptable levels of measurement error. The measures of reliability and measurement error were similar for both intrarater reliability that repeated the assessment of the movement patterns over a 48- to-72-hour period and interrater reliability that had 2 raters assess the same movement pattern simultaneously. The interrater agreement of the FMS component scores was good to excellent for the push-up, quadruped, shoulder mobility, straight leg raise, squat, hurdle, and lunge. Only 15.6% (n = 10) of the participants were identified to be at risk for injury based on previously published cutoff values. J Orthop Sports Phys Ther 2012;42(6):530-540, Epub 14 May 2012. doi:10.2519/jospt.2012.3838