Supplementary Material for: Effects of Long-Term Minimal Footwear Use on Fall-Risk and Fall Incidence in Older Adults

Introduction: Foot-related factors such as plantar foot muscle weakness, hallux valgus, hammer toe, excessive pronation, and foot pain are known causes of falls in older adults (ages > 65). Minimally cushioned footwear may naturally strengthen and provide enhanced sensory awareness to the feet, leading to reduced fall risk. The purpose of this study was to analyze the effects of long-term minimal footwear use on fall risk and fall incidence in older adults with established fall risk. Methods: Adult volunteers ages > 65 were screened for fall risk and randomized into minimal footwear (n=33) and control (sham intervention, n=32) groups. Participants performed intervention or control activities 5x/week for 16 weeks and then at least 2x/week for the remainder of the 1-year study. They were measured for fall risk using the Mini Balance Evaluation Systems Test (Mini-BESTest) at baseline, 16 weeks, and 1 year. Participants kept written journals of intervention adherence and falls, and were contacted bimonthly to collect details on falls. A mixed-effects linear model analysis was used to measure change in fall risk. The minimimal detectable change (MDC) of > 3.5 points defined “meaningful change”. Fall incidence was analyzed with number of falls per participant, proportion of fallers in each group, and fall rates per person-year. Time-to-first-fall analyses using Kaplan-Meier survival curves were used to visualize the cumulative probability of remaining fall-free over the 1-year period. The log-rank test was used to evaluate differences between groups. Results: Minimal footwear group made significant improvements in Mini-BESTest scores at both follow-up time points (16 weeks: 2.24 points, p < 0.001; 1 year: 2.62 points, p < 0.001) compared to no improvements made by control group (16 weeks: 0.108 points, p=0.794; 1 year: 0.119 points, p=0.797). At 16 weeks, 28.6% of minimal footwear group and 3.3% of control group achieved the MDC (p =0.005). At 1 year, 23.1% of minimal footwear group and 7.4% of control group achieved the MDC (p=0.111). Fall incidence was not significantly different between groups at 1 year; however, minimal footwear group had fewer falls, a smaller proportion of fallers, and longer time to first fall. For the 1-year study duration, 76.9% of minimal footwear group and 51.9% of control group remained fall-free. Conclusion: Long-term minimal footwear use resulted in meaningful improvements in balance and reduced fall risk in older adults. This type of footwear can be gradually incorporated into daily activities using our progressive schedule, or could be included in existing fall-prevention programs. This study was underpowered to detect fall incidence, and we did not see a difference in falls incidence between groups.