Intervention Design of High-Intensity Interval Training in Individuals With Spinal Cord Injury: Narrative Review and Future Perspectives

Background: Individuals with spinal cord injury (SCI) have lower levels of physical activity compared to the nondisabled population. Exercise guidelines recommend moderate or vigorous exercise to improve cardiovascular health and reduce cardiometabolic risk factors in persons with SCI. High-intensity interval training (HIIT) is a popular exercise choice and encompasses brief periods of vigorous exercise paired with intermittent periods of recovery. Objectives: This review describes the available literature on HIIT for individuals with SCI, including differences in protocol design and suggested areas of further investigation. Methods: Our institution's library system performed the comprehensive search. The primary keywords and phrases used to search included spinal cord injury, high-intensity interval training, tetraplegia, paraplegia, and several other related terms. Results: Initially 62 records were screened, and 36 were deemed outside the scope of this review. Twenty-six studies published between 2001 and 2021 fulfilled the eligibility criteria and were divided among two researchers for review and analysis. All records required persons with SCI and a standardized HIIT intervention. Study design varied widely with respect to mode of exercise, prescribed intensity, duration of performance intervals, and session duration. This variability necessitates further investigation into the specifics of a HIIT prescription and the associated outcomes for persons with SCI. Conclusion: Standardization of HIIT protocols may lead to more robust conclusions regarding its effects on cardiorespiratory fitness as well as mitigation of cardiometabolic risk factors. Meta-analyses will eventually be needed on proper dosing and session parameters to improve cardiorespiratory fitness and cardiometabolic risk factors.