The interrater and intrarater reliability of the functional movement screen

The purpose of this study was to determine the interrater and intrarater reliability of the Functional Movement Screen (FMS). Forty]Four Western Washington University athletes from various athletic teams volunteered. Twenty]one of the athletes tested volunteered to participate in a second testing session. Each athlete performed the seven components of the FMS while being evaluated by two separate testing teams. Each testing team was comprised of two members, with one member assigned to assess the sagittal plane, and the other, the frontal plane. The scores of the two members of each testing team were combined to form the total score given by each respective team. An intraclass correlation coefficient was used to determine the strength of association between the scores given by Team 1 and Team 2 during the 1st test, and the strength of association between the scores given by Team 1 during the 1st and 2nd test. The results show 0.763 for the interrater reliability (ICC 3, 1, p < 0.001) and 0.731 for the intrarater reliability (ICC 3, 1, p < 0.001) of the FMS. However, the strength of association for intrarater reliability was diminished by the lack of a definition of pain prior to the testing. When the limitation of the pain score is removed, the intrarater reliability shows 0.818 (ICC 3, 1, p < 0.001). Despite this finding, both the interrater and intrarater reliability of the FMS needs to be improved in order to use the system to track changes in athlete's movement patterns over time. The sagittal plane showed a higher correlation than the frontal plane during both interrater (ICC 3, 1 sagittal was 0.801 and frontal was 0.752) and intrarater testing (ICC 3, 1 sagittal was 0.762 and frontal was 0.713). Improving the correlation in the frontal plane scoring criteria would increase both the interrater and intrarater reliability of the total FMS score to help track changes in athlete's movement over time.