Biomechanical Mechanisms of Improved Balance Recovery to Repeated Backward Slips Simulated by Treadmill Belt Accelerations in Young and Older Adults

Aim: Exposure to repeated gait perturbations improves the balance of older adults (OAs) and decreases their risks falling, but little is known about underpinning mechanical adjustments. We aimed quantify changing temporo-spatial kinetic characteristics recovery following backward slips better understand adjustments responsible for improved balance. Methods: exposed 17 young (YAs) (25.2 ± 3.7 years) OAs (62.4 6.6 10 simulated on an instrumented treadmill by unilateral belt accelerations. measured participants (margin stability: MoS), (n steps : number necessary return a steady at least three consecutive steps), (step length), kinetics [ground reaction force (GRF) angle, lower limb joint moments] 15 each slip. The results were compared with baseline. Results: Participants in both groups MoS n exposure slips, no significant effect age was detected. During perturbed step, GRF vector directed more posteriorly during mid-stance anteriorly push-off than baseline, which resulted longer step. These maintained from first (Slip01) last (Slip10) slip, Slip10 correlated (MoS) second step Slip01, developed plantarflexor larger knee extensor moments whilst taking shorter these poorer not slips. Joint length returned normal levels Slip10. Conclusion: Young that positively (changes length, angle) those moments) discarded. All responses observed Slip01. improvements achieved refining initial strategy rather developing new one. underlying mechanics steps, associated should be monitored fall prevention interventions.