Prior knowledge of the grading criteria increases Functional Movement Screen scores in youth soccer players

We sought to determine whether familiarity with the grading criteria of the functional movement screen (FMS) impacted the outcome score in elite youth soccer players. Thirty-two trained male youth soccer players (age 17 ± 1 yr) participated in a randomized control trial. Participants were randomly assigned to evenly sized control and experimental groups who each completed the FMS on two separate occasions. Participants in the experimental group were provided the FMS grading criteria between their first and second screens. Time synchronized video footage was used to grade the FMS using standardized criteria. Structured interviews were then carried out with selected participants (n = 4) in the experimental group to establish athletes’ perception of the FMS. The experimental group had a large increase in overall FMS score from the first to the second screen in comparison to the control group (Δ2.0 ± 1.0, p < .001, d = 1.3). Scores for the deep squat, hurdle step, and rotary stability tests components of the FMS all increased in the experimental group in comparison to the control group (p < .05). Thematic analysis of the interview data suggested that the participants in the experimental group improved their understanding between good and poor technique during the FMS. These findings support the notion that FMS scores are influenced by awareness of the grading criteria. As a consequence, the FMS may not be suitable for objectively predicting injury in youth soccer players.