Influence of school backpack load on plantar foot pressure during walking in 9-11 years old girls.

OBJECTIVE

This study aimed to assess the relative load of the midfoot and the metatarsals of both feet when schoolchildren walked with backpacks of different loads.

METHODS

A group of 12 healthy girls (9.9 ± 0.8 years; 33.8 ± 6.7 kg, 1.40 ± 0.10 m) walked barefoot to assess plantar pressures during gait without load (L0%) and with a loaded backpack equal to 10% (L10%) and 20% (L20%) of their body weight. A Footscan® system (RSscan International, Belgium) was used to determine the contact area and relative pressure impulse in the midfoot and metatarsals on the dominant (DL) and non-dominant legs (NL).

RESULTS

The effect of load was significant for the contact area of the midfoot for both NL (p = 0.013) and DL (p = 0.001). In the metatarsals, there was significantly greater relative impulse during L10% compared to L0% in the first (p = 0.041) and second (p = 0.050) metatarsals of the DL. Comparing the NL and DL showed significantly greater relative impulse on the DL in the fourth metatarsal during L10% (p = 0.023), greater contact area in the fifth metatarsal during L0% (p = 0.050), and greater impulse in the midfoot during L20% (p = 0.028) on the NL.

CONCLUSIONS

The school backpack load influences relative plantar pressure distribution, especially in the midfoot. Further, our findings suggest greater propulsion of the DL and supporting function of the NL.