Feasibility of a Sprint Interval Training Program During Inpatient Spinal Cord Injury Rehabilitation: A Pilot Randomized Controlled Trial

Description of the Sprint Interval Training Condition

The SIT treatment procedures will parallel the procedures used in the successful comparative effectiveness trial of SIT versus Moderate Intensity Continuous Training (MICT) during IPR in Canada.

SIT participants will be trained to use an ergometer on a Monark 881 mechanically braked arm ergometer purchased for the study. The Monark will be mounted on a rolling table designed for this purpose, so training can take place in patient rooms or in one of several small therapy rooms adjacent to the inpatient rehabilitation unit. Sessions will begin with the physical or occupational therapist showing the participant the RPE scale (Borg 6-20) posted behind the ergometer and instructing the participant in how to report perceived exertion during each session. The therapist will position the ergometer axle at shoulder height and close enough to the participant to maintain slight elbow flexion. They will attach the heart rate monitor, validate initial recordings, assess resting RPE, and record resting HR and blood pressure. They will have the participant begin a two-minute warm-up at a self-selected speed and zero resistance followed by three 20-second intervals of all-out effort interspersed by 120 seconds of active recovery at zero resistance. During each interval, participants will be instructed to achieve a cadence of approximately 100 revolutions per minute for persons with paraplegia and approximately 85 revolutions per minute for people with tetraplegia. The therapist will adjust ergometer resistance as needed to maintain RPE ratings between 15-17. Rating of perceived exertion is a valid method to prescribe interval exercise intensity and preferable to HR. Heart rate will be recorded continuously and averaged over the entire training session excluding the warm-up and recovery periods. RPE will be measured at the end of each sprint interval training session. To accommodate training adaptation over time, the resistance on the ergometer will be increased to maintain a peripheral RPE of 16. SIT training was well-tolerated and safe in the prior IPR trial as well as in several post-acute SCI studies. Hypotension is a potential adverse event in this setting, especially immediately post-exercise. Thus, sessions will include blood pressure monitoring and surveillance for symptoms of hypotension during and after the exercise session. Adverse events will be reported to the research team for review by the DSMB. SIT training will take place approximately 3 times per week.

Description of the Home Arm Ergometer Condition

Participants randomized to receive ERGO will also take part in SIT approximately 3 times per week. Participants will undergo at least one SIT session on the consumer grade ergometer under supervision of the physical or occupational therapist. The therapist/team will demonstrate all the features of the device set up, use, and resistance adjustment to the patient and caregiver (if available). The therapist/team will problem-solve barriers to home use prior to discharge and contact the patient soon after discharge to help resolve additional problems that may have emerged. The patient will be sent home with an exercise log-sheet like the one used during IPR to guide continued training. Prior to discharge the study team will arrange to have the ergometer given to or shipped to the participant's discharge residence.