RELATIONSHIP BETWEEN FUNCTIONAL MOVEMENT SCREEN SCORES, CORE STRENGTH, POSTURE, AND BODY MASS INDEX IN SCHOOL CHILDREN IN MOLDOVA ULRIKE H. MITCHELL, A. WAYNE JOHNSON,
AND
BRYNN ADAMSON
Department of Exercise Sciences, Brigham Young University, Provo, Utah ABSTRACT
INTRODUCTION
Mitchell, UH, Johnson, AW, and Adamson, B. Relationship between Functional Movement Screen scores, core strength, posture, and body mass index in school children in Moldova. J Strength Cond Res 29(5): 1172–1179, 2015—The assessment of functionality should include parameters that consider postural control, limb asymmetries, range of motion limitations, proprioceptive deficits, and pain. An increasingly popular battery of tests, the Functional Movement Screen (FMS), is purported to assess the above named parameters. The purpose of our study was twofold: (a) to report differences in total FMS scores in children, provide preliminary normative reference values of each of the 7 individual FMS scores for both genders and report on asymmetries and (b) to evaluate the relationship between total FMS scores, age, body mass index (BMI), core strength/stability, and postural angles to explore the possibility of using the FMS in the assessment of children’s functional fitness. Descriptive data on 77 children aged 8–11 years were collected. The children performed core strength/stability exercises. Photographs were taken from a lateral view for later calculation of postural angles. The children performed the FMS while being videotaped for later review. The average total FMS score (of 21) was 14.9 (+1.9), and BMI was 16.4 (+2.2). Static posture is not related to results of the FMS. Core strength was positively correlated to the total FMS score (r = 0.31; p = 0.006). Over 60% demonstrated at least 1 asymmetry. The individual test scores indicate that none of the test items is too difficult for the children. Based on the screen’s correlation to core strength, and the fact that it identifies areas of asymmetry, we suggest to further investigate its possible use in the assessment of children’s functional fitness.
KEY WORDS FMS, postural angles, correlations, Eastern Europe, BMI
Address correspondence to Ulrike H. Mitchell, [email protected]. 29(5)/1172–1179 Journal of Strength and Conditioning Research Ó 2015 National Strength and Conditioning Association
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ore stability, or the ability to stabilize the lumbar spine and pelvis area, is a function of strong, wellsynchronized trunk muscles (18) and the product of motor control and muscular capacity of the lumbo-pelvic-hip complex (20). A stable spine serves as the foundation for functional movements, is important for athletic performance (18,20), as well as aides in postural control and balance (30). Bridging exercises are commonly used to measure core strength (18) and studies using EMG have shown that these particular exercises do indeed activate the internal/ external obliques, rectus abdominis, and erector spinae (22). However, to reflect the complexity and interplay of cognitive, perceptual, and motor functions, other parameters, such as the smoothness of movement patterns, limb asymmetries, range of motion limitations, proprioceptive deficits, postural control, and pain should be considered in the assessment of functionality (8) or functional fitness (1,12). An increasingly popular battery of tests, the Functional Movement Screen (FMS) (2), is purported to assess trunk and core strength as well as the above named parameters (2,3). It consists of a series of 7 fundamental movement patterns; the quality, and not the quantity of each of the 7 screens is scored on a 0 to 3 scale, based on specific objective criteria. It was originally designed as a screening tool for football players (17) to assess for likelihood of injury by identifying deficits and asymmetries. Duncan and Stanley (9) recently used the FMS with children aged 10 and 11 years to investigate its correlation to body mass index (BMI) and physical activity. However, there is no information on any of the component scores or asymmetries. The screen has been found to have high (27) to good (34) inter-rater and moderate (34) intra-rater reliability in the adult population, but its reliability in the pediatric population has not been shown. There is a direct relationship between core stability and posture (14). Correct posture is the position in which minimum stress is applied to each joint and minimal muscle activity is needed to maintain the position (23). It changes throughout our life span (36). Abnormal posture has been connected to disorders, pain, and muscular imbalances, that can lead to structural changes, eventually affecting bony structures (19). Most of the available posture assessments measure static, not
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Journal of Strength and Conditioning Research the clinically more relevant dynamic posture, because of its inherent controllability (31). The FMS grading criteria are partially based on one’s ability to maintain proper dynamic posture throughout functional ranges of motion, which theoretically reduces stresses imposed on each joint and minimizes muscle activity needed to perform those movements. Hence, low total FMS scores are, at least partially, a function of movement deficits (2,4) and have been linked to injury (17,28). It is therefore conceivable that the composite FMS score could possibly be a way to assess dynamic posture or even functionality. An inverse relationship between functional movements and the BMI, an indicator of obesity (35) has been found in children (9). The BMI is used to classify children and adults into “underweight,” “normal,” “overweight,” and “obese” categories, according to their mass/height ratio. Within the past decades, countries around the world have experienced dramatic increases in obesity in young and old people and both genders (21). Previous studies have examined the relationship between posture and obesity in adults, but none that we could find was conducted in the younger population. Most of the studies investigating relationships to BMI are conducted in more Westernized countries, where behavioral risk factors for obesity (32) are more available or prevalent. Our data collection occurred in the Republic of Moldova. It is one of the Europe’s poorest nations, where children do not grow up eating fast food several times a week or playing computer games for an extended period of time a day (37). The purpose of our study was twofold: (a) to report on total FMS scores in children aged 8–11 years, provide preliminary normative reference values of each of the 7 individual FMS scores for both genders and report on asymmetries and (b) to evaluate the relationship between total FMS scores, age, BMI, core strength/stability, and postural angles to explore the possibility of using the FMS in the assessment of children’s functional fitness.
METHODS Experimental Approach to the Problem
Children, aged 8–11 years, performed the FMS. It consists of a battery of 7 tests, which challenge and thus test components of functional fitness. Each child’s performance of the screen was videotaped and later analyzed. The subjects were measured for height and weight and then performed 2 timed core strength exercises. They also were photographed from the side to later obtain postural angles using a special software program. Total and composite FMS scores were reported. Some of the composite FMS scores were used to identify asymmetries between right and left range of motion and strength. The total FMS scores were then correlated to the variables we measured. This was done to identify significant relationships between the screen results and the variables that have some influence on functional fitness (i.e., body composition, core strength, and posture) as well as other variables (i.e., age and gender). To determine the influence
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of age, gender, BMI, and core strength on performance on the FMS, a regression analysis was performed using the total FMS score as the dependent variable. These data were collected in Moldova, one of the poorest countries in Europe, and compared to similar data from more affluent countries. Subjects
Ethical approval from the institutional review board at the university and the involved Moldavian schools, as well as informed consent from the parents and assent forms from the children, were obtained. A total of 77 children from Chisinau’s suburbs, in Moldova (aged 8–11 years) represent a sample of convenience as third and fourth graders were located on the same floor in the school. The subject characteristics were as follows: (M:F = 39:38), age 9.28 (60.08) years (age 8-11 years), height 138.6 (66.1) cm, weight 31.7 (65.8) kg, and BMI 16.4 (62.2) kg/m2. The students’ ages are close to the ones used in a prior study (9). Procedures
The subjects’ height was measured to the nearest onequarter inch using a calibrated wall scale and body mass was measured to the nearest tenth of a pound, using a digital scale (Healthometer Professional, Model 349KLX/320KL; Sunbeam Products, Inc., Boca Raton, FL, USA). Body mass index (kg/m2) was calculated from measures of height and body mass after being converted to centimeters and kilograms, respectively. Participants self-reported their age. All data were collected between the hours of 8 AM and noon (after breakfast and before lunch). The participants were encouraged to get a good night’s sleep before the morning of data collection, eat breakfast, and drink throughout the morning. All procedures were explained to the subjects before the actual testing procedures began. The subjects were allowed to familiarize themselves with each exercise. The subjects then performed the following core strength/ stability exercises: prone plank (22): in a prone position on the floor with the elbow angle at 908 and the forearms placed underneath the chest, pelvis raised off the floor with the body weight distributed on the forearms and toes. The children were instructed to maintain a flat back. Side plank (22): while lying on the right (left) side on the floor with the right (left) elbow bent at 908 and positioned directly under the shoulder, pelvis raised off the floor with body weight distributed on the forearms and the right (left) side of the foot. The children were instructed to maintain the position as stable as possible. Once the children started to sway or shake, the test was ended; it was also stopped after 1 minute. This time frame was chosen because this test is graded as “normal” if the person is able to maintain this position for 20–30 seconds (10). We doubled this time to ensure capturing a maximum effort. Reflective markers were placed over boney landmarks (the canthus, tragus, C7 spinous process, greater trochanter, and lateral malleolus). The children assumed a comfortable standing position and photographs were taken from a lateral view. A software program (Dartfish Connect, Dartfish, VOLUME 29 | NUMBER 5 | MAY 2015 |
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Functional Movement Screen in Children Fribourg, Switzerland) was used to mark and measure postural angles (24) (trunk angle, neck angle, gaze angle, head on neck angle, and lower limb angle). One person was used to measure all postural angles to provide consistency throughout. The children then performed 7 FMS movements: deep squat, hurdle step, inline lunge, shoulder mobility, active straight leg raise, trunk stability push-up, and rotary stability in quadruped position (Appendix 1) (4). The children were videotaped from both anterior and lateral views during the exercises. At a later time, 2 raters reviewed all videos and scored each of the FMS exercises individually according to the scoring criteria (2). Generally, a score of 3 was given when the exercise was performed completely and correctly, a 2 was given when there was compensation, faulty form or loss of alignment, a 1 was given when the movement was incomplete, and a 0 was given if the child experienced pain during any part of the exercise. The highest score of the 3 attempts was recorded and used for analysis. In case of discrepancies between the 2 sides (for those exercises that test both sides), the lower of the 2 scores was recorded. The scores were compared, and, in case of inconsistency, the video was reviewed until a consensus between the raters was reached. The scores from each of the 7 test items were summed to generate a composite score (range, 0–21). Statistical Analyses
This observational study used a cross-sectional design. Descriptive data on the subjects were compiled; FMS total and individual test scores were tabulated. Pairwise rank-
based correlations were computed using SPSS v21 (IBM Corp., Armonk, NY, USA) to evaluate the relationships between the total FMS score and age, gender, BMI, core strength, and postural angles. Because of the multiple comparisons we performed, and to reduce a type I error (incorrect rejection of a true null hypothesis, a false positive), we used the Bonferroni’s method for correcting p values (alpha #0.01). This technique of evaluating significance is considered very conservative, because it raises type II error (rejection of a true correlation, a false negative) (5). We are aware of the fact that FMS data are ordinal and that presentations of mean values are debatable. However, to be able to compare our findings to other studies, we are presenting mean values and SDs. To determine the influence of age, gender, BMI, and core strength on performance on the FMS, stepwise forward and backward regression analyses were performed using the total FMS score as the dependent variable.
RESULTS See Table 1 for the individual component and total FMS scores. Most scores are very similar between girls and boys; however, girls scored significantly (p = 0.001) higher than boys on the lunge test. The push-up and the squat exercises have the lowest average scores for both, the boys and girls. The highest average score for the girls was obtained in the lunge exercise, whereas the boys’ highest average score was achieved in the shoulder mobility screen.
TABLE 1. Individual and total scores on the FMS.*† Male (n = 39) Squat Hurdle Left Right Lungez Left Right Shoulder mobility Left Right Leg raise Left Right Push-up§ Rotary test Left Right Total FMS score
1.7 2.1 2.2 2.2 2.4 2.6 2.5 2.7 2.7 2.8 2.3 2.3 2.3 1.6 1.9 1.9 1.9 14.7
6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6
0.8 0.2 0.4 0.4 0.5 0.5 0.6 0.6 0.6 0.5 0.8 0.7 0.7 0.7 0.5 0.5 0.6 1.9
Female (n = 38) 1.7 2.2 2.3 2.3 2.8 2.8 2.7 2.6 2.7 2.8 2.5 2.6 2.6 1.3 1.9 1.9 1.9 15.1
6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6
0.7 0.4 0.5 0.5 0.4 0.4 0.5 0.5 0.5 0.4 0.8 0.7 0.7 0.7 0.4 0.4 0.5 1.9
Total (N = 77) 1.7 2.1 2.3 2.3 2.5 2.7 2.6 2.7 2.7 2.8 2.4 2.5 2.5 1.5 1.9 1.9 1.9 14.9
6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6
0.7 0.3 0.4 0.4 0.5 0.5 0.5 0.6 0.6 0.4 0.8 0.7 0.7 0.7 0.5 0.5 0.5 1.9
*FMS = Functional Movement Screen. †All values are mean 6 SD. Total FMS score = sum of the 7 individual test items in the FMS. zSignificant gender differences (p = 0.02). §Significant gender differences (p = 0.001).
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Journal of Strength and Conditioning Research Table 2 shows asymmetry distribution. Twenty-five boys (64%) and 23 girls (61%) presented with at least 1 asymmetry. There was no significant difference in number of asymmetries between boys and girls. The hurdle step was the exercise with the greatest number of children who exhibited an asymmetry, followed by the inline lunge. The exercise with the smallest number of children with asymmetry was the rotary stability exercise. Several relationships between the variables were significant at an alpha level of 0.05, but could no longer be considered significant when Bonferroni’s correction for multiple comparisons was applied. The only remaining significant (p # 0.01) correlation was between core strength and the total FMS score (r = 0.31, p = 0.006). There was no correlation between total FMS score and any of the postural angles. The forward regression model indicated that core strength was the only significant predictive variable with R2 = 0.12, F = 9.55, p = 0.003. However, when performing a regression with all variables (age, gender, BMI, and core strength), the R2 improved to 0.14.
DISCUSSION The total FMS scores for all children ranged from 10 to 19 (of a possible 21), averaging 14.7 for the boys to 15.1 for the girls with an overall average of 14.9 (Table 1). These averages are slightly higher than the ones reported by Duncan and Stanley (9), which were 13.5 and 14.5, respectively. Significant differences that can yield such discrepancy between the 2 studies will be further discussed below. Our averages are also comparable to normative data collected in young adults, average age 22 years (33). Their total FMS scores ranged from 11 to 20 and averaged 15.8 for the males and 15.6 for the females.
TABLE 2. Asymmetry distribution. Male Female Total (n = 39) (n = 38) (N = 77) One asymmetry Two asymmetries Three asymmetries Four asymmetries Range of motion Shoulder Active straight leg raise Strength Rotary stability Range of motion and strength Inline lunge Hurdle step
20 4 1
17 4 1
37 7 2
0
1
1
4 6
7 6
11 12
3
3
6
7 11
7 9
14 20
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There was no difference in number of asymmetries between boys and girls (Table 2). Forty-eight children (62%) presented with at least 1 asymmetry in either range of motion or strength, as indicated by different side to side scores in the 5 FMS tests that compared right-to-left differences (i.e., shoulder range of motion, active straight leg raise, rotary stability, inline lunge, and hurdle step). The exercise with the greatest number of asymmetries was the hurdle step (11 boys, 9 girls), followed by the inline lunge (7 boys and 7 girls). Both of these exercises are complex, as they challenge trunk stability, hip, knee, and ankle mobility, as well as gluteal strength, proprioception, and balance. These findings are in agreement with the results of a recent study by Ibrahim et al. (15) who found that dynamic balance skills in 6- to 10-year-old boys were below the adult means. This impaired dynamic postural control is age dependent and normal, due to a still developing proprioceptive system and deficits in muscle strength (15). However, asymmetry cannot always be considered a disadvantage, especially when found in the healthy active population. Motor asymmetries, such as hand preference, develop early within a young child and are considered “normal” (16), while athletes often exhibit discipline-specific asymmetries that might be necessary to excel in their particular sport (26). We believe that measuring asymmetries through the FMS could add a valuable piece of information when monitoring the development of active and inactive children. We found a statistically significant, but small (r = 0.31) positive correlation between total FMS score and core strength. Core strength was the total time the children were able to hold prone plank, as well as side plank right and left exercises using proper technique. Once the children were able to hold the proper position for 1 minute, the exercise was stopped. We had chosen this period of time because this test is graded as “normal” if the person is able to maintain this position for 20–30 seconds (10). By doubling the allotted time, we thought that we would be within the time frame that most children would be able to complete the test. Unfortunately, we were not correct in that assumption, as many children were able to hold the positions for 60 seconds and seem to have had the potential of holding those positions for even longer periods of time. Our findings are in contrast to the findings of Okada et al (29) who found no correlation between these 2 variables in healthy college-aged adults. Those authors used McGill’s 4 trunk muscle endurance tests, (25) which consist of back extensor and trunk flexor endurance tests and right/left side bridge. Although reliability of these tests has been shown, validity has not. This is possibly due to the inherent problems of not having a “gold standard” of core strength/stability to which to compare other tests. Until valid and reliable exercise tests are agreed on and uniformly used to assess core strength/stability, we will continue to get differing outcomes that are modality dependent. VOLUME 29 | NUMBER 5 | MAY 2015 |
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Functional Movement Screen in Children There was no correlation between age and total FMS score. This is possibly a function of the narrow age range we used in our study. There was also no correlation between gender and total FMS score. Nevertheless, girls scored significantly (p = 0.001) higher than boys on the lunge test. The lunge test challenges, among other, balance, just like the hurdle and rotary tests. However, there was no gender difference in the latter 2 tests. We were not able to confirm Duncan and Stanley’s (9) negative association between BMI and total FMS scores. This can possibly explained by several substantial differences that exist between their and our study: (a) age: our students were on average 1.5 years younger, (b) our average total FMS score was higher for both, boys and girls (14.7 and 15.1, respectively) compared to 13.5 and 14.5, respectively, and (c) the BMI in our students ranged from 13.0 to 23.3, averaging 16.4, whereas theirs ranged from 17.5 to 23.3 (no overall average given). In our study, 9% (7 of 77 students) were classified as “overweight,” whereas in their study 33% (19 of 58 students) were in the overweight/obese category. We believe that the latter might have played the biggest role in their finding of a relationship between FMS score and BMI. Since the students from Moldova were much leaner, as demonstrated by their average BMI being lower than the British lowest BMI, there may not have been enough depth in the spread of BMI values to produce a significant correlation. Regression models with the predictors age, gender, BMI, and core strength confirmed that neither age, gender, nor BMI did contribute to the regression model. By adding the above named variables, the predicted variance only improved by 2%. The high complement of our R2 (1 2 R2, 0.88) indicates that our tested variables poorly explain their relationship to total FMS score. Hypothesizing that the FMS is a good measure of overall functionality, our regression model seems to be missing key variables that could explain a greater percentage of the variance in the overall score. Perhaps other variables that influence functional fitness, such as a different measure of flexibility and balance or power would improve our regression model. For our static posture assessment, we used a method developed by McEvoy and Grimmer (24); it uses side-view photographs of children in a “comfortable standing” position with bony landmarks marked by adhesive markers. These markers were later used to calculate 5 postural angles. There was no correlation between the composite FMS score and any of the measured (static) postural angles. Proposing that the total FMS score represents a measure of the quality of dynamic posture and the fact that there was no correlation between dynamic and static posture, it highlights the need for a separate assessment of static and dynamic posture. Posture is influenced by many factors, one of which is obesity (7). Nevertheless, none of the 5 postural angles we measured was significantly correlated to BMI at a significance level of 0.01. The neck angle, however, was weakly correlated to
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BMI at a significance level of 0.05 (p = 0.035). The neck angle was defined as the angle between the neck as indicated by a line drawn through anatomical markers at C7 and the tragus of the ear, and the trunk, as indicated by a line drawn through anatomical markers at C7 and the greater trochanter (24). McEvoy and Grimmer (24) suggest that this angle is a measure of forward head posture (FHP); it outlines the gross direction of the C-spine; the greater the angle, the greater the FHP. The implications of FHP for health and function can be far-reaching. Forward head posture has been associated with headaches and decreased neck range of motion, (11) tempero-mandibular joint problems, and malocclusion (13) as even with carpal tunnel syndrome (6). This correlation reflects a reasonable relationship, as the center of gravity is usually shifted due to a greater midsectional gravity pull. The other parts of the spine will have to counter balance by increasing their respective curvature. A study performed in Brazil (7) evaluated the posture of morbidly obese adults and compared them to nonobese age-matched adults. They found that in the obese adult, the center of gravity was displaced anteriorly due to a protruding abdomen and the lumbar lordosis and thoracic kyphosis increased, “. resulting in a reactive cervical lordosis and leading to protrusion of the head.” It is plausible that a greater postural shift occurs with increased BMI and that our subjects were too lean to evidence this relationship. Either way, it is imperative that children and parents alike know the importance of proper posture.
PRACTICAL APPLICATIONS The total FMS scores from our study are comparable to the scores from similar-aged subjects with normal weight in Britain (9) and from healthy young adults (33). The individual test scores indicate that none of the test items is too difficult for the children, suggesting that the FMS is a viable option for the assessment of children’s fitness. We found a high number of right-to-left asymmetries (range of motion or strength related), which should be further investigated. Static posture is not related to results of the FMS. Based on the screen’s correlation to core strength, and the fact that it identifies areas of asymmetry, we suggest to further investigate its possible use in the assessment of children’s functional fitness.
ACKNOWLEDGMENTS The authors declare no conflict of interest. There was no external funding for this study.
REFERENCES 1. American College of Sports Medicine. General Principles of Exercise Prescription, in: ACSM’s Guidelines for Exercise Testing and Prescription. Baltimore, MD: Wolters Kluwer/Lippincott Williams & Wilkins, 2014. pp. 162–193. 2. Cook, G, Burton, L, and Hoogenboom, B. Pre-participation screening: The use of fundamental movements as an assessment of function—Part 1. N Am J Sports Phys Ther 1: 62–72, 2006.
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Journal of Strength and Conditioning Research 3. Cook, G, Burton, L, and Hoogenboom, B. Pre-participation screening: The use of fundamental movements as an assessment of function—Part 2. N Am J Sports Phys Ther 1: 132–139, 2006. 4. Cook, G, Burton, L, Kiesel, K, Rose, G, and Bryant, M. Functional Movement Screen Descriptions, in: Movement: Functional Movement Systems: Screening, Assessment and Corrective Strategies. Santa Cruz, California: On Target Publications, 2010. pp. 87–106. 5. Curtin, F and Schulz, P. Multiple correlations and Bonferroni’s correction. Biol Psychiatry 44: 775–777, 1998. 6. De-La-Llave-Rincon, AI, Fernandez-De-Las-Penas, C, PalaciosCena, D, and Cleland, JA. Increased forward head posture and restricted cervical range of motion in patients with carpal tunnel syndrome. J Orthop Sport Phys 39: 658–664, 2009. 7. de Souza, SAF, Faintuch, J, Valezi, AC, Sant’Anna, AF, GamaRodrigues, JJ, Fonseca, ICD, and de Melo, RD. Postural changes in morbidly obese patients. Obes Surg 15: 1013–1016, 2005. 8. de Vreede, PL, Samson, MM, van Meeteren, NL, van der Bom, JG, Duursma, SA, and Verhaar, HJ. Functional tasks exercise versus resistance exercise to improve daily function in older women: A feasibility study. Arch Phys Med Rehabil 85: 1952–1961, 2004. 9. Duncan, M and Stanley, M. Functional movement is negatively associated with weight status and positively associated with physical activity in British primary school children. J Obes 2012, 2012. 10. Dutton, M. The lumbar spine. In: Orthopaedic Examination, Evaluation, and Intervention. C. Johnson and C. Naglieri, eds. Philadelphia, PA: McGraw Hill, 2008. pp. 1492–1608. 11. Fernandez-de-las-Penas, C, Alonso-Blanco, C, Cuadrado, ML, and Pareja, JA. Forward head posture and neck mobility in chronic tension-type headache: A blinded, controlled study. Cephalalgia 26: 314–319, 2005. 12. Garber, CE, Blissmer, B, Deschenes, MR, Franklin, BA, Lamonte, MJ, Lee, IM, Nieman, DC, and Swain, DP. American College of Sports Medicine position stand. Quantity and quality of exercise for developing and maintaining cardiorespiratory, musculoskeletal, and neuromotor fitness in apparently healthy adults: Guidance for prescribing exercise. Med Sci Sports Exerc 43: 1334–1359, 2011. 13. Gonzalez, H. Forward head posture: Its structural and functional influence on the stomatognathic system, a conceptual study. Cranio 14: 71–80, 1996.
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23. Magee, D. Assessment of Posture in: Orthopedic Physical Assessment. St. Louis, MI: Saunders Elsevier, 2008. pp. 972. 24. McEvoy, M and Grimmer, K. Reliability of upright posture measurements in primary school children. BMC Musculoskelet Disord 6, 2005. 25. McGill, SM, Childs, A, and Liebenson, C. Endurance times for low back stabilization exercises: Clinical targets for testing and training from a normal database. Arch Phys Med Rehabil 80: 941–944, 1999. 26. Mclean, BD and Tumilty, DM. Left-right asymmetry in 2 types of soccer kick. Br J Sports Med 27: 260–262, 1993. 27. Minick, KI, Kiesel, KB, Burton, L, Taylor, A, Plisky, P, and Butler, RJ. Interrater reliability of the functional movement screen. J Strength Cond Res 24: 479–486, 2010. 28. O’Connor, FG, Deuster, PA, Davis, J, Pappas, CG, and Knapik, JJ. Functional movement screening: Predicting injuries in officer candidates. Med Sci Sports Exerc 43: 2224–2230, 2011. 29. Okada, T, Huxel, KC, and Nesser, TW. Relationship between core stability, functional movement, and performance. J Strength Cond Res 25: 252–261, 2011. 30. Oliver, G and Adams-Blair, H. Improving core strength to prevent injury. J Phys Educ Rec Dance 81: 15–19, 2010. 31. Raine, S and Twomey, L. Attributes and qualities of human posture and their relationship to dysfunction or musculoskeletal pain. Crit Rev Phys Rehabil Med 6: 409–437, 1994. 32. Rennie, KL, Johnson, L, and Jebb, SA. Behavioural determinants of obesity. Best Pract Res Clin Endocrinol Metab 19: 343–358, 2005. 33. Schneiders, AG, Davidsson, A, Horman, E, and Sullivan, SJ. Functional movement screen normative values in a young, active population. Int J Sports Phys Ther 6: 75–82, 2011. 34. Teyhen, DS, Shaffer, SW, Lorenson, CL, Halfpap, JP, Donofry, DF, Walker, MJ, Dugan, JL, and Childs, JD. The Functional Movement Screen: A reliability study. J Orthop Sport Phys 42: 530–540, 2012. 35. Weisell, RC. Body mass index as an indicator of obesity. Asia Pac J Clin Nutr 11: S681–S684, 2002. 36. Woollacott, M. Age-related changes in posture and movement. J Gerontol 48: 56–60, 1993.
14. Granata, KP and Wilson, SE. Trunk posture and spinal stability. Clin Biomech 16: 650–659, 2001.
37. World Trade P. Moldova Society and Culture Complete Report. Petaluma, CA: World Trade Press, 2010.
15. Ibrahim, AI, Muaidi, QI, Abdelsalam, MS, Hawamdeh, ZM, and Alhusaini, AA. Association of postural balance and isometric muscle strength in early- and middle-school-age boys. J Manip Physiol Ther 36: 633–643, 2013.
APPENDIX 1: FUNCTIONAL MOVEMENT SCREEN TESTS
16. Ingram, D. Motor asymmetries in young children. Neuropsychologia 13: 95–102, 1975.
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17. Kiesel, K, Plisky, P, and Voight, M. Can serious injury in professional football be predicted by a preseason functional movement screen? N Am J Sports Phys Ther 2: 147–158, 2007. 18. Kong, Y, Cho, Y, and Park, W. Changes in the activities of the trunk muscles in different kinds of bridging exercises. J Phys Ther Sci 25: 1609–1612, 2013. 19. Kratenova, J, Zejglicova, K, Maly, M, and Filipova, V. Prevalence and risk factors of poor posture in school children in the Czech Republic. J Sch Health 77: 131–137, 2007. 20. Leetun, DT, Ireland, ML, Willson, JD, Ballantyne, BT, and Davis, IM. Core stability measures as risk factors for lower extremity injury in athletes. Med Sci Sport Exer 36: 926–934, 2004. 21. Lobstein, T, Baur, L, and Uauy, R. Obesity in children and young people: A crisis in public health. Obes Rev 5: 4–85, 2004. 22. Maeo, S, Takahashi, T, Takai, Y, and Kanehisa, H. Trunk muscle activities during abdominal bracing: Comparison among muscles and exercises. J Sports Sci Med 12: 467–474, 2013.
This assessment involves standing with the feet about shoulder width apart (with both feet aligned in the sagittal plane). Holding a light-weight 4-foot dowel overhead (with the hands about shoulder width apart) and the elbows extended, the individual descends slowly into a squat position until the buttocks are lower than the knees. The squat should be performed with the heels flat on the floor, the head and chest facing forward, and the dowel maximally pressed overhead. As many as 3 repetitions may be performed. A passing score of 3 is given for the squat when the upper torso is parallel with the tibia or toward vertical; the femur of each leg is below horizontal; the feet remain flat on the floor in the sagittal plane; the knees are aligned over the feet; and the dowel remains in line with the feet. If the criteria for a score of 3 are not achieved, the individual is VOLUME 29 | NUMBER 5 | MAY 2015 |
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Functional Movement Screen in Children asked to perform the squat again with a 200 plank positioned under the heels (a score of 2 is given if the above criteria used for a score of 3 are reached using the heel lift, whereas a score of 1 is given if the person is not able to meet the above criteria). A score of 0 is given if the individual experiences any pain during any portion of this test.
not maintained; the dowel does not remain vertical; twisting motion is noted in the torso; the dowel and feet do not remain in the sagittal plane; or the knee does not touch behind the heel of the front foot. A score of 1 is given if a loss of balance is noted at any time during the test. A score of 0 is given if the individual experiences any pain during any portion of this test.
Hurdle Step
This assessment involves standing with the feet together (feet touching at both heels and toes), with the toes aligned and touching the base of the hurdle (the 200 3 600 plank). The physical hurdle consists of a piece of rubber tubing stretched across 2 support beams at the height of the individual’s tibial tuberosity. A dowel is positioned across the individual’s shoulders, below the back of the neck. The individual attempts to step over the hurdle with 1 foot and touch the heel to the floor while maintaining a tall spine (with minimal movement in the lumbar spine) and then returns the moving leg to the start position. During the assessment, the dowel resting on the shoulders should remain level and the hip, knee, and ankle of the moving leg should remain aligned in the sagittal plane. The hurdle should be performed slowly and under control. A total of 3 attempts bilaterally may be performed. A passing score of 3 is given when the hurdle step is performed as described above. A score of 2 is given when alignment is lost between the hip, knee, and ankle of the moving leg; movement is noted in the lumbar spine; or the dowel and hurdle do not remain parallel. A score of 1 is given if contact between the foot and hurdle occurs or there is a loss of balance. A score of 0 is given if the individual experiences any pain during any portion of this test. Inline Lunge
This assessment involves standing on top of the 200 3 600 plank in a split squat position with the feet separated by a distance (from the toe of one leg to the heel of the other leg) equal to the height from the floor to the top center of the individual’s tibial tuberosity (the same total height of the hurdle used in the previous assessment). The individual holds a dowel behind the back, touching the head, thoracic spine, and sacrum. The individual’s hand opposite the forward foot should be the hand holding the dowel at the cervical spine. The other hand holds the dowel at the lumbar spine. To perform this test, the individual simply lowers the body until the rear knee touches the plank and then returns to the start position. During the downward and upward movements of the body, the dowel must remain vertical at all times. A total of 3 attempts involving each leg may be performed. A passing score of 3 is given when the dowel remains in contact with the head, thoracic spine, and sacrum at all times; the dowel remains vertical; no torso twisting movement is noted; the dowel and feet remain in the sagittal plane; and the knee touches the plank behind the heel of the front foot. A score of 2 is given when the dowel contacts are
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Shoulder Mobility
This assessment involves standing with feet together with each hand made into a fist (and each thumb tucked within the fist). The individual then simultaneously reaches one fist behind the neck and the other behind the back, assuming a maximally adducted, extended, and internally rotated position with 1 shoulder, and a maximally abducted, flexed, and externally rotated position with the other shoulder. During the test, the hands should move in a smooth motion and should remain fisted, with the measurement equal to the distance between the 2 closest points of the hands. A total of 3 attempts may be performed. A passing score of 3 is given when the fists are within 1 hand length (note: the individual’s hand length is measured before the test by finding the distance from the distal wrist crease to the tip of the longest digit). A score of 2 is given when the 2 closest points of the fists are within one-and-a-half hand lengths. A score of 1 is given when the 2 closest points of the fists are not within one-and-a-half hand lengths. A score of 0 is given if the individual experiences any pain during any portion of this test. Active Straight-Leg Raise
The individual lies supine with the arms at the sides, palms up, and the head flat on the floor. The 200 3 600 plank is positioned under the knees with both legs straight and feet neutral (with the soles of the feet perpendicular to the floor). The test administrator positions a dowel halfway between the anterior superior iliac spine (ASIS) and the joint line of the knee and holds the dowel perpendicular to the floor. The individual is asked to lift the test limb as high as possible while maintaining the original joint angle start position of the ankle and knee. On reaching end range, the administrator checks the position of the upward limb relative to the nonmoving limb. A total of 3 attempts involving each leg may be performed. A passing score of 3 is given when the leg moves to a point so the vertical line of the malleolus resides between the midthigh and the ASIS and the nonmoving leg remains in a neutral position (with the leg in contact with the plank). A score of 2 is given if the leg moves high enough so the vertical line of the malleolus resides between the midthigh and the joint line of the knee and the nonmoving leg remains in a neutral position. A score of 1 is given when the vertical line of the malleolus resides below the knee’s joint line, while the nonmoving leg remains a neutral position. A score of 0 is given if the individual experiences any pain during any portion of this test.
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Trunk Stability Push-up
Rotary Stability
The individual lies prone with the hands extended overhead. To prepare for the assessment, men should position their hands just greater than shoulder width with their thumbs even with the top of their forehead, and women should position their hands just greater than shoulder width with their thumbs even with their chin. With the knees fully extended, the ankles neutral, and the soles of the feet perpendicular to the floor, the individual performs 1 pushup with the body lifted as a unit with no sway in the spine during the test. A passing score of 3 is given when the individual performs the push-up as described. If the individual fails to earn a 3, the hand position is adjusted and a score of 2 is given when the individual lifts his or her body as a unit with no lag in the spine (with men performing a push-up repetition with the thumbs aligned with the top of the chin and women with the thumbs aligned with the clavicle). A score of 1 is given when the individual is unable to lift his or her body as a unit with no lag in the spine (with men using the easier hand position with the thumbs aligned with the chin and women using the easier hand position with the thumbs aligned with the clavicle). A score of 0 is given if the individual experiences any pain during any portion of this test.
The individual gets into the quadruped position with the 200 3 600 plank between the hands and knees (shoulders and knees should be 908 relative to the torso, with the ankles neutral and the feet perpendicular to the floor) and the plank positioned directly below and parallel with the spine. Before movement begins, the hands should be open, with the thumbs, knees, and feet all touching the plank. The individual should first fully flex 1 shoulder while fully extending the same-side hip and knee, and then touch this same-side elbow and knee together while remaining in line with the board. Spinal flexion is acceptable as the individual brings the knee and elbow together. This may be performed bilaterally for a maximum of 3 attempts if needed. A passing score of 3 is given when the individual performs a correct unilateral repetition as described above. If a score of 3 is not attained, have the person perform a diagonal pattern. In this case, a score of 2 is given when the individual touches the opposite elbow to knee directly above the plank. A score of 1 is given when the individual is unable to perform a correct diagonal repetition (and not touch opposite elbow to knee or experiences a loss of balance during the assessment). A score of 0 is given if the individual experiences any pain during any portion of this test.
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AND
BRYNN ADAMSON
Department of Exercise Sciences, Brigham Young University, Provo, Utah ABSTRACT
INTRODUCTION
Mitchell, UH, Johnson, AW, and Adamson, B. Relationship between Functional Movement Screen scores, core strength, posture, and body mass index in school children in Moldova. J Strength Cond Res 29(5): 1172–1179, 2015—The assessment of functionality should include parameters that consider postural control, limb asymmetries, range of motion limitations, proprioceptive deficits, and pain. An increasingly popular battery of tests, the Functional Movement Screen (FMS), is purported to assess the above named parameters. The purpose of our study was twofold: (a) to report differences in total FMS scores in children, provide preliminary normative reference values of each of the 7 individual FMS scores for both genders and report on asymmetries and (b) to evaluate the relationship between total FMS scores, age, body mass index (BMI), core strength/stability, and postural angles to explore the possibility of using the FMS in the assessment of children’s functional fitness. Descriptive data on 77 children aged 8–11 years were collected. The children performed core strength/stability exercises. Photographs were taken from a lateral view for later calculation of postural angles. The children performed the FMS while being videotaped for later review. The average total FMS score (of 21) was 14.9 (+1.9), and BMI was 16.4 (+2.2). Static posture is not related to results of the FMS. Core strength was positively correlated to the total FMS score (r = 0.31; p = 0.006). Over 60% demonstrated at least 1 asymmetry. The individual test scores indicate that none of the test items is too difficult for the children. Based on the screen’s correlation to core strength, and the fact that it identifies areas of asymmetry, we suggest to further investigate its possible use in the assessment of children’s functional fitness.
KEY WORDS FMS, postural angles, correlations, Eastern Europe, BMI
Address correspondence to Ulrike H. Mitchell, [email protected]. 29(5)/1172–1179 Journal of Strength and Conditioning Research Ó 2015 National Strength and Conditioning Association
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ore stability, or the ability to stabilize the lumbar spine and pelvis area, is a function of strong, wellsynchronized trunk muscles (18) and the product of motor control and muscular capacity of the lumbo-pelvic-hip complex (20). A stable spine serves as the foundation for functional movements, is important for athletic performance (18,20), as well as aides in postural control and balance (30). Bridging exercises are commonly used to measure core strength (18) and studies using EMG have shown that these particular exercises do indeed activate the internal/ external obliques, rectus abdominis, and erector spinae (22). However, to reflect the complexity and interplay of cognitive, perceptual, and motor functions, other parameters, such as the smoothness of movement patterns, limb asymmetries, range of motion limitations, proprioceptive deficits, postural control, and pain should be considered in the assessment of functionality (8) or functional fitness (1,12). An increasingly popular battery of tests, the Functional Movement Screen (FMS) (2), is purported to assess trunk and core strength as well as the above named parameters (2,3). It consists of a series of 7 fundamental movement patterns; the quality, and not the quantity of each of the 7 screens is scored on a 0 to 3 scale, based on specific objective criteria. It was originally designed as a screening tool for football players (17) to assess for likelihood of injury by identifying deficits and asymmetries. Duncan and Stanley (9) recently used the FMS with children aged 10 and 11 years to investigate its correlation to body mass index (BMI) and physical activity. However, there is no information on any of the component scores or asymmetries. The screen has been found to have high (27) to good (34) inter-rater and moderate (34) intra-rater reliability in the adult population, but its reliability in the pediatric population has not been shown. There is a direct relationship between core stability and posture (14). Correct posture is the position in which minimum stress is applied to each joint and minimal muscle activity is needed to maintain the position (23). It changes throughout our life span (36). Abnormal posture has been connected to disorders, pain, and muscular imbalances, that can lead to structural changes, eventually affecting bony structures (19). Most of the available posture assessments measure static, not
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Journal of Strength and Conditioning Research the clinically more relevant dynamic posture, because of its inherent controllability (31). The FMS grading criteria are partially based on one’s ability to maintain proper dynamic posture throughout functional ranges of motion, which theoretically reduces stresses imposed on each joint and minimizes muscle activity needed to perform those movements. Hence, low total FMS scores are, at least partially, a function of movement deficits (2,4) and have been linked to injury (17,28). It is therefore conceivable that the composite FMS score could possibly be a way to assess dynamic posture or even functionality. An inverse relationship between functional movements and the BMI, an indicator of obesity (35) has been found in children (9). The BMI is used to classify children and adults into “underweight,” “normal,” “overweight,” and “obese” categories, according to their mass/height ratio. Within the past decades, countries around the world have experienced dramatic increases in obesity in young and old people and both genders (21). Previous studies have examined the relationship between posture and obesity in adults, but none that we could find was conducted in the younger population. Most of the studies investigating relationships to BMI are conducted in more Westernized countries, where behavioral risk factors for obesity (32) are more available or prevalent. Our data collection occurred in the Republic of Moldova. It is one of the Europe’s poorest nations, where children do not grow up eating fast food several times a week or playing computer games for an extended period of time a day (37). The purpose of our study was twofold: (a) to report on total FMS scores in children aged 8–11 years, provide preliminary normative reference values of each of the 7 individual FMS scores for both genders and report on asymmetries and (b) to evaluate the relationship between total FMS scores, age, BMI, core strength/stability, and postural angles to explore the possibility of using the FMS in the assessment of children’s functional fitness.
METHODS Experimental Approach to the Problem
Children, aged 8–11 years, performed the FMS. It consists of a battery of 7 tests, which challenge and thus test components of functional fitness. Each child’s performance of the screen was videotaped and later analyzed. The subjects were measured for height and weight and then performed 2 timed core strength exercises. They also were photographed from the side to later obtain postural angles using a special software program. Total and composite FMS scores were reported. Some of the composite FMS scores were used to identify asymmetries between right and left range of motion and strength. The total FMS scores were then correlated to the variables we measured. This was done to identify significant relationships between the screen results and the variables that have some influence on functional fitness (i.e., body composition, core strength, and posture) as well as other variables (i.e., age and gender). To determine the influence
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of age, gender, BMI, and core strength on performance on the FMS, a regression analysis was performed using the total FMS score as the dependent variable. These data were collected in Moldova, one of the poorest countries in Europe, and compared to similar data from more affluent countries. Subjects
Ethical approval from the institutional review board at the university and the involved Moldavian schools, as well as informed consent from the parents and assent forms from the children, were obtained. A total of 77 children from Chisinau’s suburbs, in Moldova (aged 8–11 years) represent a sample of convenience as third and fourth graders were located on the same floor in the school. The subject characteristics were as follows: (M:F = 39:38), age 9.28 (60.08) years (age 8-11 years), height 138.6 (66.1) cm, weight 31.7 (65.8) kg, and BMI 16.4 (62.2) kg/m2. The students’ ages are close to the ones used in a prior study (9). Procedures
The subjects’ height was measured to the nearest onequarter inch using a calibrated wall scale and body mass was measured to the nearest tenth of a pound, using a digital scale (Healthometer Professional, Model 349KLX/320KL; Sunbeam Products, Inc., Boca Raton, FL, USA). Body mass index (kg/m2) was calculated from measures of height and body mass after being converted to centimeters and kilograms, respectively. Participants self-reported their age. All data were collected between the hours of 8 AM and noon (after breakfast and before lunch). The participants were encouraged to get a good night’s sleep before the morning of data collection, eat breakfast, and drink throughout the morning. All procedures were explained to the subjects before the actual testing procedures began. The subjects were allowed to familiarize themselves with each exercise. The subjects then performed the following core strength/ stability exercises: prone plank (22): in a prone position on the floor with the elbow angle at 908 and the forearms placed underneath the chest, pelvis raised off the floor with the body weight distributed on the forearms and toes. The children were instructed to maintain a flat back. Side plank (22): while lying on the right (left) side on the floor with the right (left) elbow bent at 908 and positioned directly under the shoulder, pelvis raised off the floor with body weight distributed on the forearms and the right (left) side of the foot. The children were instructed to maintain the position as stable as possible. Once the children started to sway or shake, the test was ended; it was also stopped after 1 minute. This time frame was chosen because this test is graded as “normal” if the person is able to maintain this position for 20–30 seconds (10). We doubled this time to ensure capturing a maximum effort. Reflective markers were placed over boney landmarks (the canthus, tragus, C7 spinous process, greater trochanter, and lateral malleolus). The children assumed a comfortable standing position and photographs were taken from a lateral view. A software program (Dartfish Connect, Dartfish, VOLUME 29 | NUMBER 5 | MAY 2015 |
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Functional Movement Screen in Children Fribourg, Switzerland) was used to mark and measure postural angles (24) (trunk angle, neck angle, gaze angle, head on neck angle, and lower limb angle). One person was used to measure all postural angles to provide consistency throughout. The children then performed 7 FMS movements: deep squat, hurdle step, inline lunge, shoulder mobility, active straight leg raise, trunk stability push-up, and rotary stability in quadruped position (Appendix 1) (4). The children were videotaped from both anterior and lateral views during the exercises. At a later time, 2 raters reviewed all videos and scored each of the FMS exercises individually according to the scoring criteria (2). Generally, a score of 3 was given when the exercise was performed completely and correctly, a 2 was given when there was compensation, faulty form or loss of alignment, a 1 was given when the movement was incomplete, and a 0 was given if the child experienced pain during any part of the exercise. The highest score of the 3 attempts was recorded and used for analysis. In case of discrepancies between the 2 sides (for those exercises that test both sides), the lower of the 2 scores was recorded. The scores were compared, and, in case of inconsistency, the video was reviewed until a consensus between the raters was reached. The scores from each of the 7 test items were summed to generate a composite score (range, 0–21). Statistical Analyses
This observational study used a cross-sectional design. Descriptive data on the subjects were compiled; FMS total and individual test scores were tabulated. Pairwise rank-
based correlations were computed using SPSS v21 (IBM Corp., Armonk, NY, USA) to evaluate the relationships between the total FMS score and age, gender, BMI, core strength, and postural angles. Because of the multiple comparisons we performed, and to reduce a type I error (incorrect rejection of a true null hypothesis, a false positive), we used the Bonferroni’s method for correcting p values (alpha #0.01). This technique of evaluating significance is considered very conservative, because it raises type II error (rejection of a true correlation, a false negative) (5). We are aware of the fact that FMS data are ordinal and that presentations of mean values are debatable. However, to be able to compare our findings to other studies, we are presenting mean values and SDs. To determine the influence of age, gender, BMI, and core strength on performance on the FMS, stepwise forward and backward regression analyses were performed using the total FMS score as the dependent variable.
RESULTS See Table 1 for the individual component and total FMS scores. Most scores are very similar between girls and boys; however, girls scored significantly (p = 0.001) higher than boys on the lunge test. The push-up and the squat exercises have the lowest average scores for both, the boys and girls. The highest average score for the girls was obtained in the lunge exercise, whereas the boys’ highest average score was achieved in the shoulder mobility screen.
TABLE 1. Individual and total scores on the FMS.*† Male (n = 39) Squat Hurdle Left Right Lungez Left Right Shoulder mobility Left Right Leg raise Left Right Push-up§ Rotary test Left Right Total FMS score
1.7 2.1 2.2 2.2 2.4 2.6 2.5 2.7 2.7 2.8 2.3 2.3 2.3 1.6 1.9 1.9 1.9 14.7
6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6
0.8 0.2 0.4 0.4 0.5 0.5 0.6 0.6 0.6 0.5 0.8 0.7 0.7 0.7 0.5 0.5 0.6 1.9
Female (n = 38) 1.7 2.2 2.3 2.3 2.8 2.8 2.7 2.6 2.7 2.8 2.5 2.6 2.6 1.3 1.9 1.9 1.9 15.1
6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6
0.7 0.4 0.5 0.5 0.4 0.4 0.5 0.5 0.5 0.4 0.8 0.7 0.7 0.7 0.4 0.4 0.5 1.9
Total (N = 77) 1.7 2.1 2.3 2.3 2.5 2.7 2.6 2.7 2.7 2.8 2.4 2.5 2.5 1.5 1.9 1.9 1.9 14.9
6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6
0.7 0.3 0.4 0.4 0.5 0.5 0.5 0.6 0.6 0.4 0.8 0.7 0.7 0.7 0.5 0.5 0.5 1.9
*FMS = Functional Movement Screen. †All values are mean 6 SD. Total FMS score = sum of the 7 individual test items in the FMS. zSignificant gender differences (p = 0.02). §Significant gender differences (p = 0.001).
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Journal of Strength and Conditioning Research Table 2 shows asymmetry distribution. Twenty-five boys (64%) and 23 girls (61%) presented with at least 1 asymmetry. There was no significant difference in number of asymmetries between boys and girls. The hurdle step was the exercise with the greatest number of children who exhibited an asymmetry, followed by the inline lunge. The exercise with the smallest number of children with asymmetry was the rotary stability exercise. Several relationships between the variables were significant at an alpha level of 0.05, but could no longer be considered significant when Bonferroni’s correction for multiple comparisons was applied. The only remaining significant (p # 0.01) correlation was between core strength and the total FMS score (r = 0.31, p = 0.006). There was no correlation between total FMS score and any of the postural angles. The forward regression model indicated that core strength was the only significant predictive variable with R2 = 0.12, F = 9.55, p = 0.003. However, when performing a regression with all variables (age, gender, BMI, and core strength), the R2 improved to 0.14.
DISCUSSION The total FMS scores for all children ranged from 10 to 19 (of a possible 21), averaging 14.7 for the boys to 15.1 for the girls with an overall average of 14.9 (Table 1). These averages are slightly higher than the ones reported by Duncan and Stanley (9), which were 13.5 and 14.5, respectively. Significant differences that can yield such discrepancy between the 2 studies will be further discussed below. Our averages are also comparable to normative data collected in young adults, average age 22 years (33). Their total FMS scores ranged from 11 to 20 and averaged 15.8 for the males and 15.6 for the females.
TABLE 2. Asymmetry distribution. Male Female Total (n = 39) (n = 38) (N = 77) One asymmetry Two asymmetries Three asymmetries Four asymmetries Range of motion Shoulder Active straight leg raise Strength Rotary stability Range of motion and strength Inline lunge Hurdle step
20 4 1
17 4 1
37 7 2
0
1
1
4 6
7 6
11 12
3
3
6
7 11
7 9
14 20
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There was no difference in number of asymmetries between boys and girls (Table 2). Forty-eight children (62%) presented with at least 1 asymmetry in either range of motion or strength, as indicated by different side to side scores in the 5 FMS tests that compared right-to-left differences (i.e., shoulder range of motion, active straight leg raise, rotary stability, inline lunge, and hurdle step). The exercise with the greatest number of asymmetries was the hurdle step (11 boys, 9 girls), followed by the inline lunge (7 boys and 7 girls). Both of these exercises are complex, as they challenge trunk stability, hip, knee, and ankle mobility, as well as gluteal strength, proprioception, and balance. These findings are in agreement with the results of a recent study by Ibrahim et al. (15) who found that dynamic balance skills in 6- to 10-year-old boys were below the adult means. This impaired dynamic postural control is age dependent and normal, due to a still developing proprioceptive system and deficits in muscle strength (15). However, asymmetry cannot always be considered a disadvantage, especially when found in the healthy active population. Motor asymmetries, such as hand preference, develop early within a young child and are considered “normal” (16), while athletes often exhibit discipline-specific asymmetries that might be necessary to excel in their particular sport (26). We believe that measuring asymmetries through the FMS could add a valuable piece of information when monitoring the development of active and inactive children. We found a statistically significant, but small (r = 0.31) positive correlation between total FMS score and core strength. Core strength was the total time the children were able to hold prone plank, as well as side plank right and left exercises using proper technique. Once the children were able to hold the proper position for 1 minute, the exercise was stopped. We had chosen this period of time because this test is graded as “normal” if the person is able to maintain this position for 20–30 seconds (10). By doubling the allotted time, we thought that we would be within the time frame that most children would be able to complete the test. Unfortunately, we were not correct in that assumption, as many children were able to hold the positions for 60 seconds and seem to have had the potential of holding those positions for even longer periods of time. Our findings are in contrast to the findings of Okada et al (29) who found no correlation between these 2 variables in healthy college-aged adults. Those authors used McGill’s 4 trunk muscle endurance tests, (25) which consist of back extensor and trunk flexor endurance tests and right/left side bridge. Although reliability of these tests has been shown, validity has not. This is possibly due to the inherent problems of not having a “gold standard” of core strength/stability to which to compare other tests. Until valid and reliable exercise tests are agreed on and uniformly used to assess core strength/stability, we will continue to get differing outcomes that are modality dependent. VOLUME 29 | NUMBER 5 | MAY 2015 |
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Functional Movement Screen in Children There was no correlation between age and total FMS score. This is possibly a function of the narrow age range we used in our study. There was also no correlation between gender and total FMS score. Nevertheless, girls scored significantly (p = 0.001) higher than boys on the lunge test. The lunge test challenges, among other, balance, just like the hurdle and rotary tests. However, there was no gender difference in the latter 2 tests. We were not able to confirm Duncan and Stanley’s (9) negative association between BMI and total FMS scores. This can possibly explained by several substantial differences that exist between their and our study: (a) age: our students were on average 1.5 years younger, (b) our average total FMS score was higher for both, boys and girls (14.7 and 15.1, respectively) compared to 13.5 and 14.5, respectively, and (c) the BMI in our students ranged from 13.0 to 23.3, averaging 16.4, whereas theirs ranged from 17.5 to 23.3 (no overall average given). In our study, 9% (7 of 77 students) were classified as “overweight,” whereas in their study 33% (19 of 58 students) were in the overweight/obese category. We believe that the latter might have played the biggest role in their finding of a relationship between FMS score and BMI. Since the students from Moldova were much leaner, as demonstrated by their average BMI being lower than the British lowest BMI, there may not have been enough depth in the spread of BMI values to produce a significant correlation. Regression models with the predictors age, gender, BMI, and core strength confirmed that neither age, gender, nor BMI did contribute to the regression model. By adding the above named variables, the predicted variance only improved by 2%. The high complement of our R2 (1 2 R2, 0.88) indicates that our tested variables poorly explain their relationship to total FMS score. Hypothesizing that the FMS is a good measure of overall functionality, our regression model seems to be missing key variables that could explain a greater percentage of the variance in the overall score. Perhaps other variables that influence functional fitness, such as a different measure of flexibility and balance or power would improve our regression model. For our static posture assessment, we used a method developed by McEvoy and Grimmer (24); it uses side-view photographs of children in a “comfortable standing” position with bony landmarks marked by adhesive markers. These markers were later used to calculate 5 postural angles. There was no correlation between the composite FMS score and any of the measured (static) postural angles. Proposing that the total FMS score represents a measure of the quality of dynamic posture and the fact that there was no correlation between dynamic and static posture, it highlights the need for a separate assessment of static and dynamic posture. Posture is influenced by many factors, one of which is obesity (7). Nevertheless, none of the 5 postural angles we measured was significantly correlated to BMI at a significance level of 0.01. The neck angle, however, was weakly correlated to
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BMI at a significance level of 0.05 (p = 0.035). The neck angle was defined as the angle between the neck as indicated by a line drawn through anatomical markers at C7 and the tragus of the ear, and the trunk, as indicated by a line drawn through anatomical markers at C7 and the greater trochanter (24). McEvoy and Grimmer (24) suggest that this angle is a measure of forward head posture (FHP); it outlines the gross direction of the C-spine; the greater the angle, the greater the FHP. The implications of FHP for health and function can be far-reaching. Forward head posture has been associated with headaches and decreased neck range of motion, (11) tempero-mandibular joint problems, and malocclusion (13) as even with carpal tunnel syndrome (6). This correlation reflects a reasonable relationship, as the center of gravity is usually shifted due to a greater midsectional gravity pull. The other parts of the spine will have to counter balance by increasing their respective curvature. A study performed in Brazil (7) evaluated the posture of morbidly obese adults and compared them to nonobese age-matched adults. They found that in the obese adult, the center of gravity was displaced anteriorly due to a protruding abdomen and the lumbar lordosis and thoracic kyphosis increased, “. resulting in a reactive cervical lordosis and leading to protrusion of the head.” It is plausible that a greater postural shift occurs with increased BMI and that our subjects were too lean to evidence this relationship. Either way, it is imperative that children and parents alike know the importance of proper posture.
PRACTICAL APPLICATIONS The total FMS scores from our study are comparable to the scores from similar-aged subjects with normal weight in Britain (9) and from healthy young adults (33). The individual test scores indicate that none of the test items is too difficult for the children, suggesting that the FMS is a viable option for the assessment of children’s fitness. We found a high number of right-to-left asymmetries (range of motion or strength related), which should be further investigated. Static posture is not related to results of the FMS. Based on the screen’s correlation to core strength, and the fact that it identifies areas of asymmetry, we suggest to further investigate its possible use in the assessment of children’s functional fitness.
ACKNOWLEDGMENTS The authors declare no conflict of interest. There was no external funding for this study.
REFERENCES 1. American College of Sports Medicine. General Principles of Exercise Prescription, in: ACSM’s Guidelines for Exercise Testing and Prescription. Baltimore, MD: Wolters Kluwer/Lippincott Williams & Wilkins, 2014. pp. 162–193. 2. Cook, G, Burton, L, and Hoogenboom, B. Pre-participation screening: The use of fundamental movements as an assessment of function—Part 1. N Am J Sports Phys Ther 1: 62–72, 2006.
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Journal of Strength and Conditioning Research 3. Cook, G, Burton, L, and Hoogenboom, B. Pre-participation screening: The use of fundamental movements as an assessment of function—Part 2. N Am J Sports Phys Ther 1: 132–139, 2006. 4. Cook, G, Burton, L, Kiesel, K, Rose, G, and Bryant, M. Functional Movement Screen Descriptions, in: Movement: Functional Movement Systems: Screening, Assessment and Corrective Strategies. Santa Cruz, California: On Target Publications, 2010. pp. 87–106. 5. Curtin, F and Schulz, P. Multiple correlations and Bonferroni’s correction. Biol Psychiatry 44: 775–777, 1998. 6. De-La-Llave-Rincon, AI, Fernandez-De-Las-Penas, C, PalaciosCena, D, and Cleland, JA. Increased forward head posture and restricted cervical range of motion in patients with carpal tunnel syndrome. J Orthop Sport Phys 39: 658–664, 2009. 7. de Souza, SAF, Faintuch, J, Valezi, AC, Sant’Anna, AF, GamaRodrigues, JJ, Fonseca, ICD, and de Melo, RD. Postural changes in morbidly obese patients. Obes Surg 15: 1013–1016, 2005. 8. de Vreede, PL, Samson, MM, van Meeteren, NL, van der Bom, JG, Duursma, SA, and Verhaar, HJ. Functional tasks exercise versus resistance exercise to improve daily function in older women: A feasibility study. Arch Phys Med Rehabil 85: 1952–1961, 2004. 9. Duncan, M and Stanley, M. Functional movement is negatively associated with weight status and positively associated with physical activity in British primary school children. J Obes 2012, 2012. 10. Dutton, M. The lumbar spine. In: Orthopaedic Examination, Evaluation, and Intervention. C. Johnson and C. Naglieri, eds. Philadelphia, PA: McGraw Hill, 2008. pp. 1492–1608. 11. Fernandez-de-las-Penas, C, Alonso-Blanco, C, Cuadrado, ML, and Pareja, JA. Forward head posture and neck mobility in chronic tension-type headache: A blinded, controlled study. Cephalalgia 26: 314–319, 2005. 12. Garber, CE, Blissmer, B, Deschenes, MR, Franklin, BA, Lamonte, MJ, Lee, IM, Nieman, DC, and Swain, DP. American College of Sports Medicine position stand. Quantity and quality of exercise for developing and maintaining cardiorespiratory, musculoskeletal, and neuromotor fitness in apparently healthy adults: Guidance for prescribing exercise. Med Sci Sports Exerc 43: 1334–1359, 2011. 13. Gonzalez, H. Forward head posture: Its structural and functional influence on the stomatognathic system, a conceptual study. Cranio 14: 71–80, 1996.
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23. Magee, D. Assessment of Posture in: Orthopedic Physical Assessment. St. Louis, MI: Saunders Elsevier, 2008. pp. 972. 24. McEvoy, M and Grimmer, K. Reliability of upright posture measurements in primary school children. BMC Musculoskelet Disord 6, 2005. 25. McGill, SM, Childs, A, and Liebenson, C. Endurance times for low back stabilization exercises: Clinical targets for testing and training from a normal database. Arch Phys Med Rehabil 80: 941–944, 1999. 26. Mclean, BD and Tumilty, DM. Left-right asymmetry in 2 types of soccer kick. Br J Sports Med 27: 260–262, 1993. 27. Minick, KI, Kiesel, KB, Burton, L, Taylor, A, Plisky, P, and Butler, RJ. Interrater reliability of the functional movement screen. J Strength Cond Res 24: 479–486, 2010. 28. O’Connor, FG, Deuster, PA, Davis, J, Pappas, CG, and Knapik, JJ. Functional movement screening: Predicting injuries in officer candidates. Med Sci Sports Exerc 43: 2224–2230, 2011. 29. Okada, T, Huxel, KC, and Nesser, TW. Relationship between core stability, functional movement, and performance. J Strength Cond Res 25: 252–261, 2011. 30. Oliver, G and Adams-Blair, H. Improving core strength to prevent injury. J Phys Educ Rec Dance 81: 15–19, 2010. 31. Raine, S and Twomey, L. Attributes and qualities of human posture and their relationship to dysfunction or musculoskeletal pain. Crit Rev Phys Rehabil Med 6: 409–437, 1994. 32. Rennie, KL, Johnson, L, and Jebb, SA. Behavioural determinants of obesity. Best Pract Res Clin Endocrinol Metab 19: 343–358, 2005. 33. Schneiders, AG, Davidsson, A, Horman, E, and Sullivan, SJ. Functional movement screen normative values in a young, active population. Int J Sports Phys Ther 6: 75–82, 2011. 34. Teyhen, DS, Shaffer, SW, Lorenson, CL, Halfpap, JP, Donofry, DF, Walker, MJ, Dugan, JL, and Childs, JD. The Functional Movement Screen: A reliability study. J Orthop Sport Phys 42: 530–540, 2012. 35. Weisell, RC. Body mass index as an indicator of obesity. Asia Pac J Clin Nutr 11: S681–S684, 2002. 36. Woollacott, M. Age-related changes in posture and movement. J Gerontol 48: 56–60, 1993.
14. Granata, KP and Wilson, SE. Trunk posture and spinal stability. Clin Biomech 16: 650–659, 2001.
37. World Trade P. Moldova Society and Culture Complete Report. Petaluma, CA: World Trade Press, 2010.
15. Ibrahim, AI, Muaidi, QI, Abdelsalam, MS, Hawamdeh, ZM, and Alhusaini, AA. Association of postural balance and isometric muscle strength in early- and middle-school-age boys. J Manip Physiol Ther 36: 633–643, 2013.
APPENDIX 1: FUNCTIONAL MOVEMENT SCREEN TESTS
16. Ingram, D. Motor asymmetries in young children. Neuropsychologia 13: 95–102, 1975.
Deep Squat
17. Kiesel, K, Plisky, P, and Voight, M. Can serious injury in professional football be predicted by a preseason functional movement screen? N Am J Sports Phys Ther 2: 147–158, 2007. 18. Kong, Y, Cho, Y, and Park, W. Changes in the activities of the trunk muscles in different kinds of bridging exercises. J Phys Ther Sci 25: 1609–1612, 2013. 19. Kratenova, J, Zejglicova, K, Maly, M, and Filipova, V. Prevalence and risk factors of poor posture in school children in the Czech Republic. J Sch Health 77: 131–137, 2007. 20. Leetun, DT, Ireland, ML, Willson, JD, Ballantyne, BT, and Davis, IM. Core stability measures as risk factors for lower extremity injury in athletes. Med Sci Sport Exer 36: 926–934, 2004. 21. Lobstein, T, Baur, L, and Uauy, R. Obesity in children and young people: A crisis in public health. Obes Rev 5: 4–85, 2004. 22. Maeo, S, Takahashi, T, Takai, Y, and Kanehisa, H. Trunk muscle activities during abdominal bracing: Comparison among muscles and exercises. J Sports Sci Med 12: 467–474, 2013.
This assessment involves standing with the feet about shoulder width apart (with both feet aligned in the sagittal plane). Holding a light-weight 4-foot dowel overhead (with the hands about shoulder width apart) and the elbows extended, the individual descends slowly into a squat position until the buttocks are lower than the knees. The squat should be performed with the heels flat on the floor, the head and chest facing forward, and the dowel maximally pressed overhead. As many as 3 repetitions may be performed. A passing score of 3 is given for the squat when the upper torso is parallel with the tibia or toward vertical; the femur of each leg is below horizontal; the feet remain flat on the floor in the sagittal plane; the knees are aligned over the feet; and the dowel remains in line with the feet. If the criteria for a score of 3 are not achieved, the individual is VOLUME 29 | NUMBER 5 | MAY 2015 |
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Functional Movement Screen in Children asked to perform the squat again with a 200 plank positioned under the heels (a score of 2 is given if the above criteria used for a score of 3 are reached using the heel lift, whereas a score of 1 is given if the person is not able to meet the above criteria). A score of 0 is given if the individual experiences any pain during any portion of this test.
not maintained; the dowel does not remain vertical; twisting motion is noted in the torso; the dowel and feet do not remain in the sagittal plane; or the knee does not touch behind the heel of the front foot. A score of 1 is given if a loss of balance is noted at any time during the test. A score of 0 is given if the individual experiences any pain during any portion of this test.
Hurdle Step
This assessment involves standing with the feet together (feet touching at both heels and toes), with the toes aligned and touching the base of the hurdle (the 200 3 600 plank). The physical hurdle consists of a piece of rubber tubing stretched across 2 support beams at the height of the individual’s tibial tuberosity. A dowel is positioned across the individual’s shoulders, below the back of the neck. The individual attempts to step over the hurdle with 1 foot and touch the heel to the floor while maintaining a tall spine (with minimal movement in the lumbar spine) and then returns the moving leg to the start position. During the assessment, the dowel resting on the shoulders should remain level and the hip, knee, and ankle of the moving leg should remain aligned in the sagittal plane. The hurdle should be performed slowly and under control. A total of 3 attempts bilaterally may be performed. A passing score of 3 is given when the hurdle step is performed as described above. A score of 2 is given when alignment is lost between the hip, knee, and ankle of the moving leg; movement is noted in the lumbar spine; or the dowel and hurdle do not remain parallel. A score of 1 is given if contact between the foot and hurdle occurs or there is a loss of balance. A score of 0 is given if the individual experiences any pain during any portion of this test. Inline Lunge
This assessment involves standing on top of the 200 3 600 plank in a split squat position with the feet separated by a distance (from the toe of one leg to the heel of the other leg) equal to the height from the floor to the top center of the individual’s tibial tuberosity (the same total height of the hurdle used in the previous assessment). The individual holds a dowel behind the back, touching the head, thoracic spine, and sacrum. The individual’s hand opposite the forward foot should be the hand holding the dowel at the cervical spine. The other hand holds the dowel at the lumbar spine. To perform this test, the individual simply lowers the body until the rear knee touches the plank and then returns to the start position. During the downward and upward movements of the body, the dowel must remain vertical at all times. A total of 3 attempts involving each leg may be performed. A passing score of 3 is given when the dowel remains in contact with the head, thoracic spine, and sacrum at all times; the dowel remains vertical; no torso twisting movement is noted; the dowel and feet remain in the sagittal plane; and the knee touches the plank behind the heel of the front foot. A score of 2 is given when the dowel contacts are
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Shoulder Mobility
This assessment involves standing with feet together with each hand made into a fist (and each thumb tucked within the fist). The individual then simultaneously reaches one fist behind the neck and the other behind the back, assuming a maximally adducted, extended, and internally rotated position with 1 shoulder, and a maximally abducted, flexed, and externally rotated position with the other shoulder. During the test, the hands should move in a smooth motion and should remain fisted, with the measurement equal to the distance between the 2 closest points of the hands. A total of 3 attempts may be performed. A passing score of 3 is given when the fists are within 1 hand length (note: the individual’s hand length is measured before the test by finding the distance from the distal wrist crease to the tip of the longest digit). A score of 2 is given when the 2 closest points of the fists are within one-and-a-half hand lengths. A score of 1 is given when the 2 closest points of the fists are not within one-and-a-half hand lengths. A score of 0 is given if the individual experiences any pain during any portion of this test. Active Straight-Leg Raise
The individual lies supine with the arms at the sides, palms up, and the head flat on the floor. The 200 3 600 plank is positioned under the knees with both legs straight and feet neutral (with the soles of the feet perpendicular to the floor). The test administrator positions a dowel halfway between the anterior superior iliac spine (ASIS) and the joint line of the knee and holds the dowel perpendicular to the floor. The individual is asked to lift the test limb as high as possible while maintaining the original joint angle start position of the ankle and knee. On reaching end range, the administrator checks the position of the upward limb relative to the nonmoving limb. A total of 3 attempts involving each leg may be performed. A passing score of 3 is given when the leg moves to a point so the vertical line of the malleolus resides between the midthigh and the ASIS and the nonmoving leg remains in a neutral position (with the leg in contact with the plank). A score of 2 is given if the leg moves high enough so the vertical line of the malleolus resides between the midthigh and the joint line of the knee and the nonmoving leg remains in a neutral position. A score of 1 is given when the vertical line of the malleolus resides below the knee’s joint line, while the nonmoving leg remains a neutral position. A score of 0 is given if the individual experiences any pain during any portion of this test.
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Trunk Stability Push-up
Rotary Stability
The individual lies prone with the hands extended overhead. To prepare for the assessment, men should position their hands just greater than shoulder width with their thumbs even with the top of their forehead, and women should position their hands just greater than shoulder width with their thumbs even with their chin. With the knees fully extended, the ankles neutral, and the soles of the feet perpendicular to the floor, the individual performs 1 pushup with the body lifted as a unit with no sway in the spine during the test. A passing score of 3 is given when the individual performs the push-up as described. If the individual fails to earn a 3, the hand position is adjusted and a score of 2 is given when the individual lifts his or her body as a unit with no lag in the spine (with men performing a push-up repetition with the thumbs aligned with the top of the chin and women with the thumbs aligned with the clavicle). A score of 1 is given when the individual is unable to lift his or her body as a unit with no lag in the spine (with men using the easier hand position with the thumbs aligned with the chin and women using the easier hand position with the thumbs aligned with the clavicle). A score of 0 is given if the individual experiences any pain during any portion of this test.
The individual gets into the quadruped position with the 200 3 600 plank between the hands and knees (shoulders and knees should be 908 relative to the torso, with the ankles neutral and the feet perpendicular to the floor) and the plank positioned directly below and parallel with the spine. Before movement begins, the hands should be open, with the thumbs, knees, and feet all touching the plank. The individual should first fully flex 1 shoulder while fully extending the same-side hip and knee, and then touch this same-side elbow and knee together while remaining in line with the board. Spinal flexion is acceptable as the individual brings the knee and elbow together. This may be performed bilaterally for a maximum of 3 attempts if needed. A passing score of 3 is given when the individual performs a correct unilateral repetition as described above. If a score of 3 is not attained, have the person perform a diagonal pattern. In this case, a score of 2 is given when the individual touches the opposite elbow to knee directly above the plank. A score of 1 is given when the individual is unable to perform a correct diagonal repetition (and not touch opposite elbow to knee or experiences a loss of balance during the assessment). A score of 0 is given if the individual experiences any pain during any portion of this test.
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