Hot Topic: Functional Movement Screen-----NSCA

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                                    Hot Topic: Functional Movement Screen ------
NSCA
      Understanding Screening TestsEvery athlete is familiar with the pre-participation physical. Such examinations are designed to identify medical issues for which sports participation carries further risk. Most athletes also undergo performance testing so that coaches can track development and make comparisons to others. However, both a pre-participation physical and performance testing do not address the quality of movement.

Screening Tests and Comprehensive AssessmentsIn the mid-1990s, Gray Cook and Lee Burton noticed that omission and began to develop the Functional Movement Screen (FMS), arguably the most widely used qualitative movement test battery (1).  
The FMS and other screening tests attempt to identify movement impairments that might predispose athletes to injury or limit performance. Such assessments are increasingly popular in sports and the military, where the cost of injuries has been well documented (4,10). This article presents areas for consideration when using functional movement screening tools.
It is important to note the difference between screening tests and comprehensive assessments. Screening tests are meant to identify areas of concern quickly; however, the primary cause of the movement problem is often unclear.For example, if an athlete lands awkwardly during a screening test, it could be due to poor control of the femur by the hip musculature. But, it could also be due to poor control of the trunk, imbalances between the quadriceps and hamstrings, or relative dominance of one leg (5).

For this reason, the most effective screening tools have high sensitivity, meaning they are likely to detect any problem. Once a non-specific movement problem is identified, examiners can then evaluate more thoroughly to determine the source of the problem and plan corrective interventions. To the extent that a screening tool has limited sensitivity, it will fail to identify individuals at risk.

The Functional Movement Screen: a Case StudyIn a recent study of Marine officer candidates, O’Connor found the FMS to have a relatively low sensitivity of 0.45 (7). In this study, researchers used FMS scores ≤14 to identify at-risk Marines.

The low sensitivity in this study is a product of the fact that 29.2% of Marines scoring 14 were injured during the test period (either 38 or 68 days, with 447 and 427 Marines in each group, respectively). Interestingly, physical training test scores were just as predictive of future injury as FMS scores and had a higher sensitivity. The physical training test consisted of pull-ups, crunches, and a 3-mile run.

The O’Connor study taken in isolation does not suggest that the FMS is a poor tool for identifying injury risk through movement screening. In fact, the study found some positive predictive value for using FMS scores ≤14. (While a comprehensive review of the injury prediction efficacy of FMS studies is beyond the scope of this article, the evidence at this date is inconclusive).

As research often does, this study leaves us with more questions:

• If the fitness test is as predictive of injury as the FMS, what value does the FMS add?
• Might another screening tool (e.g., Y-balance) offer greater sensitivity in identifying those at risk?
• Will a cluster of screening measures (e.g., injury history, multiple screening tests, and psychosocial information) offer better predictive value than a single test?
  

Currently, a large-scale military study is attempting to answer these questions by collecting data on an extensive battery of tests, then tracking injuries over the course of a year. Reports from this study will begin to appear in early 2013.

The Functional Movement Screen and ReliabilityIn addition to sensitivity, another important measurement characteristic of screening tests is reliability. If the screening test of an individual changes significantly due to random variations or if multiple raters reach different conclusions, then valid inferences cannot be drawn. Onate and colleagues recently studied FMS reliability (8). They found, 1) fair to high reliability of an individual’s FMS scores when repeat testing was performed with a one-week interval, and 2) fair to high inter-rater reliability, even without FMS-certification, for all component tests except the active straight leg raise (poor reliability) (8).

Another consideration when choosing screening tests is the scope of the test battery. For example, the FMS may be considered a broad-ranging test battery, examining seven movement patterns. In contrast, the Landing Error Scoring System (LESS) and Tuck Jump Assessment are primarily designed to identify landing techniques that predispose to injury (6,11).

Drawing Conclusions About the Functional Movement ScreenWhen we attempt to match the scope of the test to the scope of the physical activity, the implication is that the FMS and other broad-ranging test batteries will likely be more effective for general needs (e.g., tactical athletes, general population), while more targeted tests such as the LESS and Tuck Jump Assessment will likely be more effective to screen athletes in the jumping-landing sports (2).

An important practical consideration for movement screening interventions is the degree to which noted impairments can be addressed afterward. Myer and colleagues have integrated screening and corrective interventions with the goal of ACL injury prevention (5). Planning for such integration is likely necessary to change injury outcomes significantly.

While such integrated screening-intervening programs are challenging to administer, a potential tool for increasing efficiency is to combine corrective activities with warm-up drills, in effect meeting two objectives with one activity. Several standardized programs have shown effectiveness in this regard (9).

Finally, it is important to note the complexity and variability of human movement. Many factors such as verbal feedback, external task constraints (e.g., load magnitude and rate), or adaptations to training will affect a given neuromuscular response to a movement challenge (3). Frost and colleagues also note the possibility of natural day-to-day or repetition-to-repetition variation in the component movements of screening tests.

It is likely that screening of functional movement quality will remain an imperfect tool when taking this possibility into consideration. Performance specialists using such imperfect tools are encouraged to, 1) choose screening tests with good measurement qualities and relevance for their activity, and 2) integrate movement screening with targeted interventions so that the performance team (trainers, coaches, athletes) can efficiently implement corrective strategies.