A single session of trip-specific training modifies trunk control following treadmill induced balance perturbations in stroke survivors

Background: Individuals with stroke are at significant risk of falling. Trip-specific training is a targeted training approach that has been shown to reduce falls in older adults and amputees by enhancing the compensatory stepping response required to prevent a fall. Still, individuals with stroke have unique deficits (e.g. spasticity) which draws into question if this type of training will be effective for this population. Objective: Evaluate if a single session of trip-specific training can modify the compensatory stepping response (trunk movement, step length/duration, reaction time) of individuals with chronic stroke. Methods: Sixteen individuals with unilateral chronic stroke participated in a single session of trip-specific training consisting of 15 treadmill perturbations. A falls assessment consisting of 3 perturbations was completed before and after training. Recovery step kinematics measured during the pre- and post-test were compared using a repeated measures design. Furthermore, Fallers (those who experienced at least one fall during the pre- or post-test) were compared to Non-fallers. Results: Trip-specific training decreased trunk movement post perturbation. Specifically following training, Trunk flexion was 48 and 19 percent smaller on the small and medium perturbations at the end of the first compensatory step. Fallers (9 out of 16 subjects) post-training resembled Non-Fallers pre-training. Specifically, Trunk flexion at the completion of the first step during small and medium perturbations was not different between Fallers post-training and Non-Fallers pre-training. Still enthusiasm was tempered because Trunk flexion at the largest perturbation (where most falls occurred) was not changed and therefore total falls were not reduced as a result of this training. Significance: Our results indicate that trip-specific training modifies the dynamic falls response immediately following trip-like treadmill perturbations. However, the incidence of falls was not reduced with a single training session. Further study of the implications and length of the observed intervention effect are warranted.