Use the FMS to Assess Mobility, Not Performance

A new study on rugby players confirmed that the functional movement screen is best used to gauge mobility and flexibility, as opposed to athletic performance.

The Functional Movement Screen, or FMS, is a tool I and many coaches utilize to improve the health of our clients. Lack of function alone may account for a huge proportion of injuries and pain that athletes experience. However, like any good tool, the reliability of the FMS demands rigorous scientific inquiry, as demonstrated in a study published this month in the Journal of Strength and Conditioning Research.

In this study, the researchers tested rugby athletes for a period of about eight months, from pre-season to post-season. The researchers performed the FMS and also tested the athletes’ performances on a handful of strength and speed exercises, like bench press and forty-meter sprint time. The aim of the study was to determine if the FMS could be used reliably and to see if the athletes would improve without specific movement interventions.

The screening was indeed reliable. The researchers tested the athletes on all of the FMS tests, amounting to twelve total: the squat, hurdle step (right and left), lunge (right and left), shoulder mobility (right and left), active straight leg raise (right and left), push up, and rotary stability (right and left). Out of the twelve assessments in the FMS, only the most complex test had any degree of variance between test administrators. This means the test works. Unfortunately, the rugby players didn’t actually improve their scores over the eight months of testing, even though they did get stronger and faster.

We must consider the small range of possible scores in a movement screen like this one. Each one of the twelve exercises performed was rated on a scale of one to three, so there wasn’t a lot of variation possible in the scoring system. For most exercises, the players scored a two, which means they couldn’t fully complete the exercise, but didn’t experience any pain. It’s possible they did improve, but not enough to be reflected with such a limited range of scores.

In this study, there was no control group that performed exercises designed to improve their FMS scores. This study was primarily conducted to determine if increases in performance would yield increases in function, which they did not. For example, the players got stronger at the bench press over the season, but couldn’t perform an overhead squat any better than they could at the start. If you’ve ever done an overhead squat before, you know that it would take more time to improve your score on that, than it would to lift more on your bench press, especially if you’re only working on the latter.

So we know that functional movement is not linked directly to improvement in other athletic qualities. We also know that for athletes who do not score off the charts on the FMS, it’s relatively safe to go about developing other athletic traits, so long as we take care to not push the limits of movements.

This study has important applications for athletes who perform relatively poorly on a FMS, despite being strong and fast. Coaches need to pay specific attention to improving the scores in order to increase an athlete’s chances of remaining injury-free and attaining the pinnacle of performance.


1. Mark Waldron, et. al., “The reliability of Functional Movement Screening (FMS) and in-season changes in physical function and performance among elite rugby league players,” Journal of Strength and Conditioning Research Publish Ahead of Print, DOI: 10.1519/JSC.0000000000000270

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