Repeated Predictable Loading and Unpredictable Unloading Waist-Pull Perturbations to Elicit Protective Stepping Responses: Clinical Correlations with Fall History in Active Older Adults

Background: Impairments in reactive stepping responses predispose older adults to fall-risk. Prior research has determined methods to assess reactive stepping responses, however those methods lack objectivity or feasibility for use in clinical settings. Spring Scale Test (SST) is a valid, reliable, safe and a clinical tool that measures reactive stepping responses as a percent of total body weight (% TBW). However, there is a need to determine whether SST derived stepping response measures associate with falls in older adults. Thus, this study performed a retrospective analysis of the published data by DePasquale and Toscano (2009) to examine whether SST obtained reactive stepping response measures correlate with fall history in older adults. Methods: Fifty-eight older adults (mean age = 80.80 ± 7.23) underwent SST, with loading and unloading of waist-pull forces to elicit and assess reactive stepping responses. Stepping threshold, % TBW limit, step frequency at stepping threshold and % TBW limit were noted for both anterior direction (rear stepping) and posterior direction (forward stepping) waist-pull perturbations. Previous two-year fall history was recorded. Pearson’s correlation was performed to determine the association between SST stepping response measures and fall history. Results: Individuals with fall history exhibited a lower stepping threshold and %TBW limit values compared to individuals who did not fall. Fall history significantly correlated with %TBW limit (r = 0.786, p = 0.05 for rear stepping; r = 0.743, p = 0.05 for forward stepping). Stepping threshold at rear stepping correlated more with fall history (r = 0.557, p = 0.01) compared to stepping threshold at forward stepping(r = 0.30, p = 0.01). No significant associations were noted for step frequency at stepping threshold and %TBW with fall history. Conclusion: The SST derived stepping response measures might have the potential to identify older adults at risk of falls. Future studies are required in a larger sample to determine whether SST derived stepping response measures can be utilized by healthcare professionals to predict future fall-risk in older adults.