Dynamic stability during perturbed human walking

The recovery strategies after a trip vary depending on several conditions. The location, timing, and magnitude of the trip are determining factors as well as the speed of the subject when the trip occurs. Previous studies focused on the trip and the recovery without systematically varying the walking speed. Individuals at high risk of falls alter their walking speed in an effort to be more stable in case of a trip. However, no studies to date have analyzed the recovery strategies when walking faster and slower than preferred. Using a treadmill and a specially designed tripping device allows for subjects to be unsuspectingly tripped at different times and different speeds while measuring kinematic and EMG responses. The tripping device included a cuff attached to the left ankle of the subject and would stop the left ankle when signaled by the experimenter. From these findings we can infer that slower walking does aid in trip recovery. Although a more robust study should be performed to confirm the consistency of these findings across multiple populations, it seems that slower walking does aid in trip recovery.