Does participation in a physical activity program impact upon the feet of overweight and obese children?

Objectives: To investigate the effect of a weight-bearing physical activity program on foot structure and plantar pressures generated by overweight/obese children.

Design: Descriptive study.

Methods: Measurements were collected for a sample of children participating in an obesity treatment trial (mean ± SD 8.5 ± 1.1 y, 29.4% boys, 2.63 ± 0.61 body mass index z-score). Children were randomised to physical activity (physical activity; n = 24) and no physical activity (no physical activity; n = 10) groups. Foot structure was characterised using anthropometry, an emed® AT-4 system quantified pressure distributions and Actigraph accelerometers objectively measured physical activity.

Results: After 6 months there was a significant decrease in body mass index z-score (physical activity: p = 0.002, no physical activity: p < 0.001), an increase in foot length (physical activity: p < 0.001, no physical activity: p < 0.001) and foot height (physical activity: p < 0.001, no physical activity: p = 0.008), although no change in physical activity. Pressure–time integrals increased after 6 months (lateral midfoot; physical activity: p = 0.036, medial forefoot; physical activity: p = 0.002, no physical activity: p = 0.013, middle forefoot; physical activity: p = 0.044, lateral forefoot; physical activity: p = 0.043) but there were no between-group differences in plantar pressures after the physical activity program.

Conclusions: Although changes to foot structure and function in overweight/obese children could not be attributed to participating in the physical activity program, their developing feet may still be at risk of pain and discomfort due to higher plantar pressures and pressure–time integrals. Further research investigating ways to reduce plantar pressures generated by overweight/obese children while they are physically active is warranted.