Figure 2: Arch Index Measurement ARCH HEIGHT STIFFNESS AND ARCH HEIGHT INDEX ACROSS GRADES P.T. Williams, C.M. Wilburn, M.E. Dupiton, M.A. Morris, J.E. Mcroy, S.L. Price, L.L. Smallwood, M.W. Kitchens, N.H. Moore, B.E. Decoux, L.E. Brewer, W.H. Weimar Florida A&M University, Tallahassee, FL ABSTRACT PURPOSE: The aim of this study was to identify alterations in arch height index & stiffness in youth across various grade levels. METHODS: Twenty-nine participants in various grade levels (1,5,8) volunteered to participate in this study (16 female, 13 males). The participants walked at a self-selected pace across a Zeno electronic gait (Figure 1) mat using the ProtoKinetics Motion Analysis Software (PKmas) to capture the characteristics during the middle of the gait cycle. Foot anthropometric measurements were computed in SPSS to compare arch height index and stiffness across the various grade levels. RESULTS: Two one way mixed model ANOVAs was employed to determine if significant differences existed in these measures across grades. Significant differences were noted for both right and left arch height stiffness (RAHS & LAHS) for first grade vs fifth grade (p = .004, p=.012) and first vs eighth grade (p= .003, p= .008). Left arch height index (LAHI) presented a significant difference for first vs eighth (p = .023) graders and right arch height index (RAHI) for first vs eighth (p = .025) graders. CONCLUSION: Based on the defining characteristics of foot structure it can be concluded that the greatest amount of change in foot development occurs from first to fifth grade and first to eight grade. Despite the lack of significant differences during the middle school years, further research is needed to determine how maturation influences arch development. INTRODUCTION The foot is a complex structure that endures ongoing development throughout life. Its purpose is to support, stabilizes and diminishes the impact of forces on the lower limb during walking. Arch height and arch height stiffness have been defining characteristics of foot architecture4. During these developing stages, internal and external factors can influence the formation of specific foot architecture. There is limited research regarding foot architecture using the arch height index measurement system among African-American school aged children in K-12. The aim of this study is to analyze arch height differences in stiffness & index in school-age children in the developmental grades (1st, 5th & 8th) to determine if there is a difference in foot architecture, thereby providing useful information with regard to their choices, successes or failures in athletic events. METHODS Twenty-nine students in grades 1, 5 and 8 volunteered to participate in this project . Child assent was obtained after parental permission was granted. The arch height was measured for each child, while sitting and standing of each foot. This measure was taken by measuring the height of the navicular bone using the arch height index measurement apparatus (Figure 2). Other anthropometric data was also collected so that the arch height index could be calculated. These measures included: foot length, truncated foot length, foot girth, height, weight and shoe size. Two between subject’s ANOVA’s were computed to determine if the arch height index as well as the arch height stiffness were different across these three grades. REFERENCES Butler RJ et al. (2008). Journal of American Podiatric Med Assoc 98:102-102 Ezema CI, et al., Flat foot and associated factors among primary school children: A cross-sectional study, Hong Kong Physiotherapy Journal (2013) https://www.samuelmerritt.edu/marc/resources Zifchock RA et al. (2006). Foot Ankle Int, 27:367-372 RESULTS Two one way mixed model ANOVAs was employed to determine if significant differences across grades. Significant differences were noted for both right and left arch height stiffness (RAHS & LAHS) for first grade (p=.004) vs fifth grade (p=.012) and first (p=.003) vs eighth grade (p= .008) (Table 1). First vs eighth graders presented significantly different arch height index measures for both the right and left feet (p= .023 (left)), (p=.025 (right)) (Table 2). No significant differences were noted between fifth and eighth grade for AHI. DISCUSSION The results from this study indicate that the greatest amount of change in arch development occurs between the first to fifth grades and first to eight grades. As children age, it appears that their arch become flatter and stiffer. This would suggest that morphological changes occur that indicate an increase in the capability of the foot to with stand deformation. Despite the lack of significant differences during the middle school years, further research is needed to determine how maturation influences arch development, even after middle school. Table 1 Figure1: Zeno Gait mat Table 2 Figure 2: Arch Index Measurement