This study adds to the literature in the area by providing data examining the association between weight status and functional movement screen scores in children. Results of this study suggest that functional movement is related to weight status with functional movement being poorer in children classified as obese across all 7 tests in the functional movement screen, compared to their normal weight peers. In this respect the results of the present study are confirmatory of prior work  that reported total FMS score to be significantly and inversely related to BMI in a group of 10–11 year old children. However, in contrast, the present study clearly builds on the work presented by Duncan and Stanley  by presenting data across the individual tests within the Functional Movement Screen. This is important as individual scores on the 7 tests within the FMS as these are purported to relate to the range of activities involved in human tasks of daily living  and represents how the present study adds to the area. While the use of a composite score of functional movement, such as that by prior research  provides a holistic indication of the total quality of an individual’s or group’s functional movement. The use of a composite score solely, as is the case in the prior work by Duncan and Stanley , limits the diagnostic value of the Functional Movement Screen because it does not enable researchers or practitioners to understand whether overweight status had a specific impact on all functional movement skill. Nor does it highlight or whether there was patterning to the effect that overweight and obesity might have on specific functional movements (e.g., those requiring strength over balance, upper body over lower body functional movements). As such, prior work presenting the association between functional movement and weight status in children  might be considered limited in comparison to the data presented int he present study. Similar data have also been reported for a sample of young adults by Schneiders et al.  but without examining the effect of weight status. The data presented in this manuscript might therefore be considered as also extending current knowledge on expected ranges of functional movement performance in children.
This study also supports prior research in adults which has suggested that excess weight results in functional limitations [5, 25] and assertions that children display altered functional movement as a consequence of excess weight [5, 6]. However, in the context of the present study and population examined, it is possible that functional limitation may have existed prior to overweight/obesity. Therefore, it may be that functional limitation may lead to children being less physically active, gaining fat mass and will not develop the Fundamental Movement Patterns that underpin performance to the same level of mastery as children who do not have a functional limitation . In the same way, children who are not functionally limited may more engage in more daily physical tasks and thus, engage in more regular practise of the Fundamental Movement Patterns that underpin performance. These children will consequently become more proficient in performance of Fundamental Movement Patterns resulting in greater physical self efficacy, increased likelihood of participation in physical activity and lower likelihood of unhealthy weight. This suggestion is conjecture although prior studies have identified that greater self-efficacy is associated with better functional performance and less functional limitation in older adults  and recent research has highlighted that movement training and physical activity programmes are effective in enhancing fundamental movement skills in children . Although fundamental movement skills are discrete from functional movement, functional movement skills are the prerequisites for the performance of fundamental movement skills.
To the authors’ knowledge this is the first study to examine associations between weight status and the individual tests within the FMS in a pediatric population. The data presented here are however important as they highlight those children who are overweight and obese present maladaptive movement patterns needed to accomplish tasks of daily life. Moreover, in the context of the current study the condition of overweight versus obese cannot simply be equated in terms of FMS outcomes. The results of this study suggest a clear differentiation in the pattern of scoring for functional movement between normal weight, overweight and obese children. Obese children evidenced significantly poorer functional movement scores on all the tests within the FMS in comparison to normal weight children. However, overweight children only performed more poorly than their normal weight peers in the deep squat and shoulder mobility tests. The subsequent poorer performance by obese children compared to their overweight peers in the hurdle step, in line lunge, shoulder mobility and active straight leg raise tests might also suggest a graded deterioration in functional movement in normal weight compared to overweight and overweight compared to obese children. As this is the first study to compare individual test scores in children across normal weight, overweight and obese children (as opposed to combining overweight and obesity in one category) further research is needed to determine if this represents a dose–response in relation to the effect of excess body mass on functional movement.
Over time, these movement patterns coupled with the effect of excess weight on joint loading are likely to lead to orthopaedic abnormality in later life . Moreover, such suboptimal movement patterns can prevent individuals from undertaking health enhancing physical activity .
Mechanisms for the impact of overweight and obesity on functional movement. Have been proposed by prior authors  but these are based on adult studies due to the dearth of data in children. Overweight and obesity has been suggested to lead to alterations in the musculoskeletal system that place overweight individuals at higher risk of musculoskeletal pain . This increased musculoskeletal pain then results in restricted range of movement. Some studies in children and adolescents [28, 29] have evidenced changes in foot structure and plantar pressure distribution, as a result of structural adaptation to excess weight, which was suggested to lead to functional movement complications. Research with older adults  has also highlighted that a BMI of 30 kg/m2 or greater is significantly associated with functional limitation. The data presented in the current study would, at least in part, support this assertion in children. The suggestion that there is a reciprocal relationship between functional movement/motor competence, physical activity and weight status is not new and the results presented here align with the conceptual model previously presented by Stodden et al. . However, other research with older adults has additionally suggested that the ratio of fat free mass (FFM) to body mass is important as individuals with higher FFM are more likely to be functionally proficient than those with lower FFM . Future research would therefore be welcomed in this area but using pediatric samples.
Despite this, the data presented here support the need for interventions to improve functional movement in British children generally but those who are overweight and obese specifically. It is also important to note that although the children in the present study had been familiarised with the movements involved in the FMS, it may be that there are practice effects in the FMS. Studies have yet to ascertain whether this is the case.
When comparing these study results in relation to gender, one other study to date  has reported specifically on the use of the tests within the Functional Movement Screen in a pediatric population. In a relatively small sample of 39 middle school children, Burton et al.  reported that higher total FMS scores in girls compared to boys were as a result of better performance in the deep squat, in line lunge, straight leg raise and shoulder rotation. The range of total FMS scores reported in their study  are similar to those documented in this study. However, no overall gender difference was reported here, contrasting the total FMS results reported by Burton et al. . Despite this, the results of the present study would agree with assertions made by Burton et al.  that girls outperform boys in functional movements requiring hamstring flexibility and balance whilst boys outperform girls in tests where muscular strength is required. However, these results also agree with data presented by Duncan and Stanley  which reported no gender differences in total FMS scores of 10–11 year old children. One potential explanation for the gender differences in particular functional movements reported in the present study has been children’s physical activity socialization . Opportunities to practice functional movements related to strength performance tend to be higher in boys, since significant others (parents, peers) may often prioritise participation in these activities for boys whereas girls tend to more regularly participate in sports such as dance or gymnastics [33, 34] which refine movement and postural control skills such as balancing [35–37]. In such a case the movements required to perform such activities would best relate to the hurdle step and straight leg raise tests within the functional movement screen as used in the present study and may, at least in part, explain the gender differences reported in this study. Similar to the present study, Schneiders et al.  reported gender differences of the same magnitude in the straight leg raise and trunk stability push-up in a population of young adults.
Although there are various measures that have been used in studies to quantify fundamental movement skills [33, 34, 36, 37], the functional movement screen employed in this study provides a way to assess the quality of specific movement patterns that relate to movement rather than the ability to perform a function (e.g., to throw a ball at a target as an evaluation throwing skill). Moreover, although the FMS as used in the present study has most readily been used with athletic groups [13, 17], the FMS was conceptualised to provide a practical screen to identify biomechanical deficits in fundamental movement that may limit human performance [13, 17]. Research has also examined functional movement using the FMS in young adults , firefighters , following worksite yoga intervention  and in children . Thus, the use of the FMS appears to a practical and participant friendly way by which to evaluate movement in children. However, there may be remit for future research to specifically validate the FMS with performance of everyday life activities in a pediatric population. Furthermore, we also acknowledge that the FMS as used in the current study may not be the best option to evaluate movement quality in children in a field setting.
It is also important to note that the results presented here do not necessarily suggest a clinical need for those children exhibiting poor functional movement at their present age. However if those children who exhibited suboptimal movement patterns persist into adolescence and adulthood and are coupled with overweight/obesity this may lead to further musculoskeletal problems of clinical significance including chronic pain, knee osteoarthritis and early hip replacement (See  for a review) at a later stage.
There are also potential confounding variables that may have influenced the results presented in the present study. Habitual physical activity may represent one such confounding variable and the lack of assessment of this variable should be considered as a limitation in the current study. Other individual variables such as socio-economic status and ethnic group may also potential influence functional movement and were also not accounted for in the current study. The present sample did not have a sufficient balance of ethnic groups nor was it drawn across multiple socio-economic status groups for these confounding variables to be accounted for. It may also be important for future studies to assess or control for such confounders when considering the impact of overweight/obesity on functional movement in children. Furthermore, longitudinal designs would be welcome to understand whether overweight/obesity leads to a lack of physical activity and subsequent poorer functional movement or whether suboptimal functional performance actually restricts ability to engage in health enhancing physical activity and leads to subsequent unhealthy weight gain. This exploratory study is also limited by a small sample size and larger scale studies would be welcome to verify the claims made here. In addition, cause and effect in relation to weight status and functional movement could not be determined in the present sample.