Biomechanical properties of shoes and risk of falls in older adults

Objectives: To determine the relationships between the biomechanical properties of shoes worn in a cohort of healthy older adults and the risk of falling. Design: Nested case-control study, comparing biomechanical measurements of shoes worn by those who reported a fall with measurements of shoes worn by age- and sex-matched nonfallers engaged in broadly similar activities. Setting: On-site measurements where falls occurred. Participants: A cohort of 1,371 older adults, of whom 327 reported a fall and 327 served as age- and sex-matched controls. Measurements: Shoe measurements related to lateral stability (heel height and width, critical tipping angle), foot position sense (heel-collar height, sole thickness, and sole flexibility), and the shoe/surface interface (foresole material, shoe-to-ground coefficient of friction, sole contact area). Results: Greater heel height was associated with increased risk of a fall (P for trend=.03), whereas greater sole contact area was associated with reduced risk (P for trend=.005). Shoe characteristics related to foot position sense bore little apparent relation to fall risk. Coefficients of friction of 0.5 or greater were observed in 93% of shoes measured, indicating that very few were excessively slippery. Conclusion: Certain measurable properties of shoes were found to be significantly related to risk of falls in older adults. Wearing shoes with low heels and large contact area may help older adults reduce the risk of a fall in everyday settings and activities.