Construct Validation of the FMS: Relationship between a Jump-Landing Task and FMS Items
Sports injuries and athletic performance are complex areas, which are characterized by manifold interdependencies. The landing error scoring system (LESS) is a valid screening tool to examine bilateral jump-landing mechanics. Whereas, the Functional Movement Screen (FMS) items are thought to operationalize flexibility and motor behaviour during low intense bodyweight patterns. The aim of the study was to explore possible interdependency of the diagnostic information of these screening tools. 53 athletes (age 23.3±2.1 yrs.) were tested in a sport scientific lab. In detail, 31 professional soccer players (3rd Division) and 22 collegiate athletes were studied. Linear, partial correlational and cluster analysis were performed to examine possible trends. Generally, the sportsmen achieved a LESS score of 6.6±2 and a jumping height of 37±7.8cm. Partial correlational analysis indicates that trunk control (r=0.4; p<0.01) is moderately related to landing mechanics, which in turn was negatively related on LESS height (r=-0.67, p<0.01). In addition, clustering showed by trend, that a higher active straight leg raise (ASLR) score is related to better landing mechanics (ASLR score 1: LESS 6.9±1.8; n=15 vs. ASLR score 3: LESS 5.6±2.1; n=10). On the task-specific level, jump-landing mechanics were directly related to jumping performance in this cohort with poor mechanics. On unspecific analysis level, kinetic chain length (ASLR) and trunk control has been identified as potential moderator variables for landing mechanics, indicating that these parameter can limit landing mechanics and ought to be optimized within the individual´s context. A potential cognitive strategy shift from internal (FMS) to external focus (LESS) as well as different muscle recruitment patterns are potential explanations for the non-significant linear relationship between the FMS and LESS data.