Age-related changes in distribution of body weight on soles of feet for selected actions and postures.

We investigated age-related changes in the distribution of body weight on soles of feet in 878 healthy subjects ranging from 5 to 80 years of age. By modifying Morton's Staticometer, we constructed an instrument for measuring body-weight distribution over three areas of soles of the feet, the big toe (inner forefoot), the other four toes combined (outer forefoot) and the heels for both feet, thus a total of six areas. The weights in the six areas were recorded at the completion of nine selected actions and postures. We observed that for inhaling and exhaling standing postures, generally younger subjects had a ratio close to 1:2:3 for weights recorded for the inner toe:outer toes:heels as observed by Morton, but elderly subjects had a smaller value than 3 for the heel. The body-weight distribution tended to shift from heels to outer toes across age groups, which was more distinctly observed in women than in men.