Foot strike pattern in children during shod-unshod running

The purpose of this study was to determine the foot strike patterns (FSPs) and neutral support (no INV/EVE and no foot rotation) in children, as well as to determine the influence of shod/unshod conditions and sex. A total of 713 children, aged 6 to 16 years, participated in this study (Age = 10.28 ± 2.71 years, body mass index [BMI] = 19.70 ± 3.91 kg/m2, 302 girls and 411 boys). A sagittal and frontal-plane video (240 Hz) was recorded using a high-speed camcorder, to record the following variables: rearfoot strike (RFS), midfoot strike (MFS), forefoot strike (FFS), inversion/eversion (INV/EVE) and foot rotation on initial contact. RFS prevalence was similar between boys and girls in both shod and unshod conditions. In the unshod condition there was a significant reduction (p < 0.001) of RFS prevalence both in boys (shod condition = 83.95% vs. 62.65% unshod condition) and in girls (shod condition = 87.85% vs. 62.70% unshod condition). No significant differences were found in INV/EVE and foot rotation between sex groups. In the unshod condition there was a significant increase (p < 0.001) of neutral support (no INV/EVE) both in boys (shod condition = 12.55% vs. 22.22% unshod condition) and in girls (shod condition = 17.9% vs. 28.15% unshod condition). In addition, in the unshod condition there is a significant reduction (p < 0.001) of neutral support (no foot rotation) both in boys (shod condition = 21.55% vs. 11.10% unshod condition) and in girls (shod condition = 21.05% vs. 11.95% unshod condition). In children, RFS prevalence is lower than adult's population. Additionally, barefoot running reduced the prevalence of RFS and INV/EVE, however increased foot rotation.