Interval training elicits higher enjoyment versus moderate exercise in persons with spinal cord injury

Background: High intensity interval training (HIIT) is a robust and time-efficient approach to improve multiple health indices including maximal oxygen uptake (VO(2)max). Despite the intense nature of HIIT, data in untrained adults report greater enjoyment of HIIT versus continuous exercise (CEX). However, this has yet to be investigated in persons with spinal cord injury (SCI). Objective: To examine differences in enjoyment in response to CEX and HIIT in persons with SCI. Design: Repeated measures, within-subjects design. Setting: University laboratory in San Diego, CA. Participants: Nine habitually active men and women (age = 33.3 +/- 10.5 years) with chronic SCI. Intervention: Participants performed progressive arm ergometry to volitional exhaustion to determine VO(2)peak. During subsequent sessions, they completed CEX, sprint interval training (SIT), or HIIT in randomized order. Outcome Measures: Physical activity enjoyment (PACES), affect, rating of perceived exertion (RPE), VO2, and blood lactate concentration (BLa) were measured. Results: Despite a higher VO2, RPE, and BLa consequent with HIIT and SIT (P < 0.05), PACES was significantly higher (P = 0.03) in response to HIIT (107.4 +/- 13.4) and SIT (103.7 +/- 12.5) compared to CEX (81.6 +/- 25.4). Fifty-five percent of participants preferred HIIT and 45% preferred SIT, with none identifying CEX as their preferred exercise mode. Conclusion: Compared to CEX, brief sessions of submaximal or supramaximal interval training elicit higher enjoyment despite higher metabolic strain. The long-term efficacy and feasibility of HIIT in this population should be explored considering that it is not viewed as more aversive than CEX.