Factors Associated With Walking Adaptability and Its Relationship With Falling in Polio Survivors

Objective: To explore factors associated with walking adaptability and associations between walking adaptability and falling in polio survivors. Design: Cross-sectional study. Setting: Outpatient expert polio clinic. Participants: Polio survivors (N=46) who fell in the previous year and/or reported fear of falling. Interventions: Not applicable. Main Outcome Measures: Walking adaptability was assessed on an interactive treadmill and operationalized as variable target-stepping and reactive obstacle avoidance performance. Further, we collected walking speed and assessed leg muscle strength, balance performance (Berg Balance Scale and Timed-Up-and-Go Test), balance confidence (Activities-specific Balance Confidence scale), ambulation level, orthosis use, fear of falling, and number of falls in the previous year. Results: With walking speed included as a covariate, muscle weakness of the most affected leg and balance confidence explained 54% of the variance in variable target-stepping performance. For reactive obstacle avoidance performance, muscle weakness of the most affected leg and knee extensor strength of the least affected leg explained 32% of the variance. Only target-stepping performance was significantly related to the number of falls reported in the previous year (R²=0.277, P<.001) and mediated the relation between leg muscle weakness and balance confidence with falling. Conclusion: Our exploratory study suggests that leg muscle weakness and reduced balance confidence limit walking adaptability in polio survivors. Because poorer target stepping rather than obstacle avoidance performance was associated with falling, our results indicate that a limited ability to ensure safe foot placement may be a fall risk factor in this group. These findings should be confirmed in a larger sample.