Evaluating the impact of different slipping velocities on falls and non-falls induced by a programmable split-belt...

Split-belt treadmills have become increasingly popular for investigating the body's responses to induced slips, yet no study has examined the effects of different slipping velocities on the occurrence of falls and fall rates. This study investigated how different slipping velocities impact the number and rate of falls. Using a programmable and instrumented splitbelt treadmill, we assessed the effect of three slipping velocities, which were determined based on each participant's preferred walking speed (PWS): 0.5×PWS, 1×PWS, and 2×PWS. Twelve healthy young adults participated and completed eight trials (six trials (three slipping velocities × two feet) + two false trials (no slip perturbation)). The sequence of the eight trials was randomized, and the slip perturbation (a belt that runs forward) was applied at random between twenty-six and fifty steps. A trial was labeled as falling if the loading force between a safety harness and the ceiling was more than 30% of the participant's body weight; otherwise, it was labeled as non-falling. A chisquare analysis was applied to non-falls (0) and falls (1) for the three slipping velocities and two feet. The main effect of the slipping velocities was significant, regardless of the slipped feet. The 1×PWS and 2×PWS resulted in significantly higher fall rates than the 0.5×PWS. The findings suggest that slipping velocities need to be carefully chosen depending on applications (e.g., perturbation-based training without falling or evaluating the body's responses to induced falls).Clinical Relevance- This study offers valuable insights for clinicians by demonstrating that tailored slip perturbation velocities can facilitate balance recovery and evaluate reactive fall responses during treadmill-based interventions. These findings could guide the development and clinical adoption of treadmill-based fall prevention and rehabilitation protocols, aiming to enhance safety and outcomes for individuals at risk of falling.