Age-related differences in foot structure and function.

The aim of this study was to compare foot characteristics and plantar force and pressure patterns in young and older people. Fifty young (mean age 20.9+/-2.6 years) and 50 older (mean age 80.2+/-5.7 years) people without foot problems underwent tests of foot posture, range of motion, strength, sensation and deformity. Plantar force and pressure distribution during gait were evaluated using a floor-mounted resistive sensor mat system. Older participants exhibited flatter/more pronated feet, reduced range of motion of the ankle and 1st metatarsophalangeal joints, a higher prevalence of hallux valgus, toe deformities and toe plantarflexor weakness, and reduced plantar tactile sensitivity. Plantar pressure analysis revealed decreased magnitude of forces and pressures under the heel (-13% to 16%), metatarsophalangeal joints (-11% to 16%) and hallux (-19% to 25%), but greater relative contact time under the heel (+21%), midfoot (+14%) and metatarsophalangeal joints (+5% to 8%) in older participants. Multiple regression analysis revealed that these age-related differences could be largely explained by differences in step length and various foot characteristics, particularly foot posture and the severity of hallux valgus. These findings indicate that ageing is associated with significant changes in foot characteristics which contribute to altered plantar loading patterns during gait.