Background: The Functional Movement System (FMS) is a pre-participation evaluation tool used among physical therapists, strength coaches, personal trainers, and athletic trainers to identify movement deficiencies. The FMS displays intra-rater and interrater reliability but has been challenged regarding the validity of the composite score and its use to predict injuries. Also, several studies have examined the impact of a weight vest on the FMS screen in firefighters. The purpose of this study is to investiigate how load may impact the FMS scoring system, specifically the Inline Lunge (ILL) and overall movement using a weight vest based on percent bodyweight (BW) in collage age athletes 18-24 years old. The primary investigator hypothesizes that load will impact the ILL with 10% or 20% BW load. Study Design: A quasi-experimental design was used to properly assess the impact of load on the scoring criteria of the FMS’s ILL> A p-value of <.05 was set to determine statistical significance. A Wilcoxon Signed Ranked test was used to determine significance between BW, 10% and 20% additional load. A Spearman Rho test was used to determine the magnitude of the relationship. Furthermore, a ROC curve was used to show how sensititve the ILL was to load. A 2×2 table was used to establish significance and effect size. Purpose: This study aimed to establish the sensitivity of the FMS ILL to load and look at the differences between the right and lef sides when a load is applied. Methods: A convenience sample of 23 student-athletes from Saint Xavier University performed the Inline Lunge as instructed from the Functional Movement System (FMS). The participants performed the FMS ILL without load, and if a score of 2 or 3 were attained on each leg, participants would retest wearing a weighted vest to include 10% of their bodyweight (BW). If a score of 2 or 3 were achieved on each leg, an additional load would be added to the weight vest equaling 20% of their bodyweight to produce a final FMS score for each leg. Results: The ROC analysis showed that the left side under 20% load was sensitive and proved to be an accurate test. In the comparison between right and left sides, a Wilcoxon Signed Rank Test showed that a load of 10% BW did not elicit a significant difference compared to the bodyweight inline lunge on the right side. However, a difference was shown on the left. A load of 20% resulted in a significant difference on both right and left sides compared to a bodyweight lunge. When comparing right and left sides to loads of 10% and 20%, significance was reached on the left side only. Large effect sizes were seen with 10 and 20% loads on the left side. Loads of 10 and 20% on the right side showed a moderate effect size but lacked significance. When comparing limbs, the 10% load was moderate but lacked signficance, where the load of 20% was large and significant. Conclusions: The results of this study indicated that the addition of load does play a role in the scoring of the FMS inline lunge on both the left side and right side with 20%, a load of 10% on the left side, and a change of load on the left side from 10-20%. Sensitivity was seen only on the left side with a 20% load. Limb differences were explicitly seen with loads of 20% and a change of load from 10-20% on the left side. The results of this study will help practitioners understand how to load their clients more effectively in knee dominant movements, understand the FMS screen more indepth, utilize applying load based on bodyweight to establish proper resistance to the knee dominant movement, and understand limb asymmetries better.
