Task-Specific Versus Impairment-Based Training on Locomotor Performance in Individuals With Chronic Spinal Cord Injury: A Randomized Crossover Study

Abstract

Background. Many research studies attempting to improve locomotor function following motor incomplete spinal cord injury (iSCI) focus on providing stepping practice. However, observational studies of physical therapy strategies suggest the amount of stepping practice during clinical rehabilitation is limited; rather, many interventions focus on mitigating impairments underlying walking dysfunction. Objective. The purpose of this blinded-assessor randomized trial was to evaluate the effects of task-specific versus impairment-based interventions on walking outcomes in individuals with iSCI. Methods. Using a crossover design, ambulatory participants with iSCI >1-year duration performed either task-specific (upright stepping) or impairment-based training for up to 20 sessions over ≤6 weeks, with interventions alternated after >4 weeks delay. Both strategies focused on achieving higher cardiovascular intensities, with training specificity manipulated by practicing only stepping practice in variable contexts or practicing tasks targeting impairments underlying locomotor dysfunction (strengthening, balance tasks, and recumbent stepping). Results. Significantly greater increases in fastest overground and treadmill walking speeds were observed following task-specific versus impairment-based training, with moderate associations between differences in amount of practice and outcomes. Gains in balance confidence were also observed following task-specific vs impairment-based training, although incidence of falls was also increased with the former protocol. Limited gains were observed with impairment-based training except for peak power during recumbent stepping tests. Conclusion. The present study reinforces work from other patient populations that the specificity of task practice is a critical determinant of locomotor outcomes and suggest impairment-based exercises may not translate to improvements in functional tasks. Clinical Trial Registration URL. https://ichgcp.net/clinical-trials-registry/NCT02115685" title="See in ClinicalTrials.gov">NCT02115685.

Keywords: gait; high-intensity training; rehabilitation.

Conflict of interest statement

Disclosures/Conflict of Interest: none

Figures

Figure 1.

CONSORT flow diagram of randomized crossover design. One participant enrolled in task-specific training first was lost prior to initiating impairment-based training

Figure 2.

Differences in primary locomotor outcomes of A) fastest speed, B) peak treadmill speed, and secondary outcomes of C) 6MWT and D) peak RST power; BSL and POST indicated for both first and second training interventions in order received; dark lines indicate task-specific training, dashed lines indicate impairment-based training, filled squares denote task-specific first, impairment-based second; open triangles denote impairment-based first, task-specific second.

Figure 3.

Correlations between differences in steps/sessions between training conditions (steps during task-specific minus steps during impairment-based) vs differences in changes (Δ) in selected outcome measures (i.e., ΔFS = changes in task-specific minus changes following impairment-based interventions); A) ΔFS, B) Δ6MWT (both p