What are the effects of obesity in children on plantar pressure distributions?

OBJECTIVE: This study examined the effects of obesity on static and dynamic plantar pressure distributions displayed by children. DESIGN: Field-based experimental data on body mass index (BMI) and plantar pressures were collected for 10 obese children and 10 nonobese controls. SUBJECTS: In all, 10 obese (age 8.8+/-2.0 y, BMI 25.8+/-3.8 kg m(-2)) children matched to 10 nonobese children (age 8.9+/-2.1 y, BMI 16.8+/-2.0 kg m(-2)), for gender, age and height. MEASUREMENTS: Height and weight were measured to calculate BMI. Right and left foot plantar pressures were obtained using an AT-4 emed pressure platform (Novel(gmbh), Munich) to calculate the peak force and pressure experienced under areas of each child's feet during static and dynamic conditions. RESULTS: While standing, the obese children generated significantly higher forces over a larger foot area and experienced significantly higher plantar pressures compared to their nonobese counterparts (41.8+/-17.7; 30.1+/-12.0 N cm(-2,) respectively; P<0.022). Similarly, while walking, the obese children generated significantly higher forces over all areas of their feet, except the toes. Despite distributing these higher forces over a significantly larger foot area when walking, the obese children experienced significantly higher plantar pressures in the midfoot (P<0.003) and under the second to fifth metatarsal heads (P<0.006) compared to the nonobese children. CONCLUSIONS: It is postulated that obese children are at an increased risk of developing foot discomfort and/or foot pathologies due to increased plantar loads being borne by the small forefoot bones. Furthermore, continual bearing of excessive mass by children appears to flatten the medial midfoot region during walking. As the long-term consequences of these increased plantar loads are currently unknown, it is recommended that the effects of obesity on the structural and functional characteristics of obese children's feet be further investigated.