The effect of reactive balance training on responses to novel unexpected balance perturbations: a feasibility study

Trial design Pilot study embedded within an assessor-blinded parallel randomized controlled trial. Objective To determine the feasibility of using unexpected and novel balance perturbations to assess the efficacy of reactive balance training. Methods Participants: Community-dwelling adults with chronic stroke who could walk independently without a gait aid for at least 10 m. Interventions: Reactive balance training, using manual and internal perturbations, or ‘traditional’ balance training (control group). Training took place for one hour per session, twice per week for six weeks. Outcome: Proportion of unexpected slips triggered as intended; s tate anxiety, perceptions of situations, and participants’ subjective responses to the unexpected slip perturbation; and spatiotemporal and kinematic features of unperturbed and perturbed walking (step length, width, and time, and mechanical stability) pre- and post-training. Randomisation: Blocked stratified randomization. Blinding: Assessors were blinded to group allocation. Results Numbers randomised: 28 participants were randomized (15 to reactive balance training, 13 to control). Of these, nine reactive balance training group participants and seven control participants were eligible and consented to additional data collection for the pilot study. Numbers analysed: 12 participants (six per group) completed the post-training unexpected slip data collection and were included in analysis of the pilot objective. Outcome: All unexpected slips triggered as intended. Overall, participants did not report increased state anxiety or any concerns about the unexpected slip. Analysis of spatiotemporal and kinematic data suggested better stability following the unexpected slip for reactive balance trained participants than control participants; however, there were also between-group differences in spatiotemporal and kinematic features of walking pre- and post-training. Conclusions Unexpected slips are feasible in research. However, their value as outcomes in clinical trials may depend on ensuring the groups are balanced on prognostic factors. Trial registration ISRCTN05434601 Funding Canadian Institutes of Health Research. ### Competing Interest Statement The authors have declared no competing interest. ### Clinical Trial ISRCTN05434601 ### Clinical Protocols ### Funding Statement This study was supported by the Canadian Institutes of Health Research (MOP 133577). The authors also acknowledge the support of the Toronto Rehabilitation Institute; equipment and space have been funded with grants from the Canada Foundation for Innovation, Ontario Innovation Trust, and the Ministry of Research and Innovation. These funding sources had no role in the design of this study and did not have any role during its execution, analyses, interpretation of the data, or decision to submit results. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The trial was approved by the University Health Network research ethics board (protocol number: 14-7428). I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present work are contained in the manuscript