Training parameters and effects of high-intensity interval training in patients with spinal cord injury: a review of literature

Abstract Background Inactivity among patients with spinal cord injury causes further deterioration of cardiorespiratory function and muscle strength. A variety of exercise modes, including high-intensity interval training (HIIT), have been applied to this population to aid them in maintaining good physical and mental health. However, an extensive review of the training parameters and efficacy of HIIT in patients with spinal cord injury remains lacking. Objectives This review aims to summarize the training parameters and effects of HIIT on cardiorespiratory function, muscle architecture, and strength among patients with spinal cord injury. Methods All studies were identified from electronic databases from 2005 to 2020. All articles were reviewed, and data were extracted independently by two reviewers. Risk of bias was assessed using the NIH Quality Assessment Tool for Before-After (Pre-Post) Studies with No Control Group. The methodological quality of randomized control trial (RCT) studies was measured using the PEDro scale. Results A total of 305 studies were identified from all listed databases. After screening, twelve experimental studies comprising three case studies, six quasi-experimental, and three RCTs were selected. Four studies were rated as good, and two studies were rated as fair for the methodology quality of the quasi-experimental study. All three RCT studies scored 5/10 or higher on the PEDro scale. A wide range of training parameters were found for HIIT training. Improvement of VO2peak was reported in seven studies. Information on the effect of HIIT on muscle strength was limited and inconclusive. Conclusion Despite limited evidence, HIIT could be considered effective in improving cardiorespiratory fitness in patients with spinal cord injury. However, whether or not HIIT can significantly improve muscle strength among this population remains inconclusive because of insufficient quality evidence.