Effects of obesity on dynamic plantar pressure distribution in Chinese prepubescent children during walking.

The purpose of this study was to examine the effects of obesity on dynamic plantar pressure distribution during walking for prepubescent children. A footscan(®) plantar pressure plate system was used to collect the gait data. Fifty obese prepubescent children and fifty non-obese prepubescent children walked across the plate at preferred speed while barefoot. SPSS11.5 was used for analysis and significance is defined as p<0.05. Obese subjects had longer midstance duration (p=0.004) and shorter propulsion duration (p=0.047) compared to non-obese subjects. The peak pressures under the metatarsal heads II-V, midfoot and heel lateral (p=0.004, p=0.03, p=0.004) were significantly higher for obese subjects. The time to peak pressures under the toes II-V, the metatarsal heads IV, V and midfoot (p=0.008, p=0.009, p=0.01, p=0.006), and pressure rate under the heel medial and lateral heel (p=0.03, p=0.009) were also significantly higher. In addition, the arch index for the left foot (p=0.01), the left and right foot axis angle (p=0.027, p=0.03) were significant larger among obese subjects. We also found that obese subjects had significantly higher relative regional impulses of contact with the plate at the midfoot of left foot (p=0.01) and the forefoot of right foot (p=0.047). There were also differences in foot balance during the midstance and propulsion phase (p=0.0004, p=0.03) and in pronation extent during midstance and propulsion phases between left and right foot in the obese group (p=0.03, p=0.01). In conclusion, the obese children have weaker walking stability with flatter foot pattern, the larger foot axis angle and dynamic plantar pressure distribution changes compared to non-obese children.