Shoe-stiffness modification to improve gait in older adults: a feasibility study

Waking is critical to maintaining functional independence and participating in activities of daily living. Waking performance is determined in large part by the function of the ankle plantar flexor muscles – muscles that are disproportionately afflicted by aging. Thus, cost-effective interventions aimed at preserving or restoring ankle function are critical for improving mobility in the elderly. During walking, older adults typically produce smaller peak ankle joint moments and consume metabolic energy more rapidly. A prior study from our research group has shown that increasing foot stiffness via carbon fiber insoles can restore ankle function and enhance ankle moment generation. It is currently unclear whether such shoes stiffness modifications could enhance the mechanics and energetics of walking in older adults. The purpose of this study was to examine the effects of shoe-stiffness modifications on metabolic energy cost and walking performance in older adults. We hypothesized that walking with higher shoe stiffness would: 1) reduce metabolic energy cost and 2) increase 6-min walk distance. Participants completed three visits: two visits to assess their functional walking capacity (6-min walk test), and one visit to measure lower limb kinetics and metabolic energy cost while walking with and without 2 stiffness of carbon fiber insoles. Data thus far displayed a slope-dependent effect of shoe stiffness on metabolic cost of walking. This feasibility studies provides promising preliminary support that shoe-stiffness modifications can enhance walking performance in older adults.