According to the authors of this study, Musculoskeletal Disorders (MSDs) are among the leading causes of morbidity (illness/disease/disorder) and mortality (death) among working aged adults and armed service members. In their introduction, the researchers review statistics from Operation Iraqi Freedom and Operation Enduring Freedom show that with some 34,000 medical evacuations the most common cause was an MSD (24% of all medical evacuations) while combat injuries were the cause of only 14% of evacuations.
MSDs are also quite common in basic training. For example, over a several year period, the Marine Corps Recruit Depot in San Diego CA had 22,000 recruits for 12 weeks of basic training. During this time they recorded 53,000 lost training days at a cost of $16.5 million per year.
Because musculoskeletal injuries are so common and associated with significant morbidity, the researchers sought to accurately identify those at highest risk. Previous studies have found several factors associated with higher risk of MSD in armed services recruits including:
- low levels of physical activity prior to basic training
- previous injury history
- high running mileage
- low fitness levels
- cigarette smoking
- older age
- biomechanical factors
However, even with these known MSD risk factors, there is still a great need for a more sensitive tool that more accurately predicts who is at risk for an MSD. To this end, the sports medicine community has become interested in functional movement and core stability programs and the belief that these programs may improve fitness, performance and assist in injury prevention.
Functional Movement Screening (FMS) moves away from static biomechanical testing for deficiencies (e.g. sit and reach testing), and instead uses comprehensive functional movements and core stability to establish an individual’s functional platform. Previous FMS studies have been smaller retrospective studies (e.g., professional football players) that looked for associations between injuries and FMS (retrospective studies are considered weak at identifying causative factors). Another interventional study, with firefighters, showed that training and improving FMS scores resulted in decreased lost time due to injury as compared to historical injury rates.
This current study represents the first large prospective study of FMS that seeks to validate the concept that screening or correcting functional deficits will either predict or minimize injury or improve performance.
The FMS is a series of 7 tests that are each scored as shown below.
- Hurdle Step
- Shoulder Mobility
- Active Straight Raise
- Push Ups
- Rotary Stability
Scoring is on a 0-3 scale with a maximum combined score of 21, representing a perfect score, for the series:
- 3 = completed as instructed, free of movement compensation & pain
- 2 = movement completed pain free, but with some compensation
- 1 = could not complete as instructed
- 0 = subject has pain with movement
Limited data are available on the use of FMS for screening in an apparently healthy population. More often FMS has been used in rehabilitation. However, the authors note that recent studies have demonstrated good inter-rater reliability following training in the test procedure.
874 male candidates consented to the FMS testing. All subjects were aged 18-30 years. 427 of the candidates were in a 10-week candidate training program and 447 candidates were in a shorter 6-week training program. Each subject particapted all 7 FMS tests. All subjects also completed the standard Marine Corps Physical Fitness test. This fitness test includes;
- Pull-ups to exhaustion
- 2-min abdominal crunch
- 3-mile run for time
- The long and short (10 & 6 week) training groups had similar demographics, characteristics, and health histories
- The long training group had slightly lower physical fitness scores
- The long training group had significantly higher incidences for overuse, traumatic, and serious injuries. However, when looking at injuries per 1000 person-days, the short training group had higher incidences for “any” and traumatic injuries; the two groups did not differ on overuse or serious injuries when controlling for exposure to training with person-days.
The mean FMS score among all candidates was 16.6 out of a possible 21
- Approximately 10% of candidates had an FMS score below 14, which is considered low
- Only 0.2% of all candidates had scores at or below 10
- Only 0.2% of candidates had a perfect score of 21
Results — Bimodal Distribution
- FMS scores at or below 14 are associated with more risk of any injury
- FMS scores between 15-17 were associated with lower risk
- FMS scores at and above 18 were associated with more risk of an injury
Results – Physical Fitness
- Fitness scores were just as predictive of future injury as FMS scores and had a higher sensitivity in correctly identifying those likely to develop MSDs. Those with higher fitness scores were significantly less likely to develop injuries.
The FMS was not shown to be a strong predictor of injury in this training study. Fitness scores proved to be as predictive, or better so, of injuries as was the FMS score. This may be due to the fact that this was a homogenous population with a narrow range of ages, fitness levels, and physical capabilities. The authors suggest testing this tool with a more general population of armed services candidates, not the more selective population of marine candidates.
Based on these results, FMS does not appear to be a good predictor of future injury potential, at least not for this highly motivated military population. The authors speculate that FMS may be a better predictor in more diverse populations, but more research would be necessary to test this hypothesis.
What Does this Mean to Ergonomists?
MSD prevention is a subspecialty for many ergonomists, and understanding which methodologies are effective at predicting their future occurance is of great interest and value. Unfortunately, FMS does not appear to be a reliable means to predict MSDs.
Functional screening in general, in fact, is viewed by some as a questionable means for injury prevention. In their view, potential job candidates may be discriminated against if a functional test suggests a higher likelihood of future injury. They might argue that it is very "un-ergonomic" to focus intervention efforts on the individual — on the person — rather than on the work system.
Instead, traditional ergonomics practice focuses on the design of the physical and cognitive processes and environments. Armed with an understanding of the types of risk factors that can lead to injury, or other process failures like poor quality or productivity, ergonomists focus on designing the system to protect the human and enhance performance. In doing so, ergonomists make systems and environments more effective and acceptable for a larger population. However, when the focus is placed on the individual, the process can quickly become one of discrimination, eliminating people from unsafe environments, rather than eliminating unsafe conditions from those environments.
Ergonomics seeks to create more inclusive work, home and leisure environments and experiences by making them more accommodating to a larger population of people. While FMS and other screening methodologies may have their place, in military environments and duties, for example, they should not be viewed as a replacement for a sound ergonomics approach in general industry.
Screening can lead to exclusion and discrimination, while ergonomics should lead to opportunity and inclusion.
O’CONNOR, FRANCIS G.; DEUSTER, PATRICIA A.; DAVIS, JENNIFER; PAPPAS, CHRIS G.; KNAPIK, JOSEPH J., Functional Movement Screening: Predicting Injuries in Officer Candidates, Medicine & Science in Sports & Exercise, December 2011 – Volume 43 – Issue 12 – p 2224–2230
At the time of this review, a full copy of this article was available for purcahse at: http://journals.lww.com/acsm-msse/Abstract/2011/12000/Functional_Movement_Screening___Predicting.2.aspx
This article originally appeared in The Ergonomics Report™ on 2011-12-13.