The effect of aging on the hardness of foot sole skin: a preliminary study

Foot problems are common in older people and altered biomechanical parameters under the foot sole has been proposed as a key risk factor for foot lesions. Therefore the aim of this study was to investigate the age-related differences in the hardness of foot sole skin.

Twenty-six healthy volunteers without foot problems, aged from 26 to 65 years, were examined using shore meter. The hardness of the foot sole under the big toe (area 8), 1st metatarsal head (area 5), 3rd metatarsal head (area 6), 5th metatarsal head (area 7), mid foot (area 3, 4) and hind foot (area 1, 2) were measured. The correlation between age and hardness of foot sole was examined and comparisons were made between two age groups.

From the result we observe statistical significant (p<0.05; p<0.01; p<0.005) differences in hardness between age groups in hind foot, metatarsal heads (1st, 3rd & 5th) and big toe. Strong positive correlations between age and hardness of the foot sole were found at the big toe (r=0.57; p<0.005), 1st metatarsal head (r=0.567; p<0.00001), 3rd metatarsal head (r=0.565; p<0.00001), 5th metatarsal head (r=0.55; p<0.00001), and heel (r=0.59; p<0.0001).

The loss of compliance in the foot sole may be one of the factors responsible for the higher incidence of foot problems in aged people. Routine foot examination and appropriate therapeutic intervention including the use of foot orthoses and optimal hardness of foot wear insole may help to prevent the serious foot injuries.