Sprint Interval Training During Inpatient Rehabilitation After Spinal Cord Injury

Abstract

During inpatient rehabilitation, arm-ergometry training is utilized to improve the physical capacity of patients with a sub-acute spinal cord injury (SCI) to a level that is desirable for performing activities of daily living (ADLs). Previous work has demonstrated that ≥ 20 minutes of moderate-intensity continuous training (MICT) during inpatient rehabilitation, at a frequency of ≥ 3 times per week, is useful for increasing the physical capacity of these patients. However, considering that inpatient rehabilitation is an intensive program, and given the trend towards a shortened length of stay during inpatient rehabilitation, performing MICT on the arm-ergometer can consume a valuable amount of therapy time. Low-volume sprint interval training (SIT) is a time-efficient alternative to MICT for improving indices of physical fitness in healthy and diseased populations. To date, however, there are no published studies comparing SIT to MICT in persons with sub-acute SCI undergoing inpatient rehabilitation.The purpose of this thesis was to evaluate the efficacy of a five-week, thrice weekly low-volume SIT protocol on the arm-ergometer and compare fitness outcomes to traditional MICT in patients with sub-acute SCI undergoing inpatient rehabilitation. Participants with sub-acute SCI undergoing inpatient rehabilitation were recruited and randomly allocated to the SIT or MICT training group. Both types of training utilized the same 2 min. warm-up and 3 min. cool-down. SIT consisted of 3 x 20 sec. “all-out” cycle sprints (≥ 100% of peak power output [POpeak]), interspersed with 2 min. of low activerecovery (≈ 10% of POpeak; total time commitment, 10 mins). MICT involved 20 min. of arm cycling (45 – 60% of POpeak; total time commitment, 25 mins). SIT elicited a higher relativheart rate response, and ratings of perceived exertion than MICT. Following training, we found similar improvements in maximal and sub-maximal physical capacity across groups. Both exercise modes were equally well tolerated, and enjoyable, and there were no differences in self-efficacy across groups. The significance of this work is that it is the first randomized-controlled trial comparing SIT to MICT on the arm-ergometer in individuals with sub-acute SCI undergoing inpatient rehabilitation. The fact that SIT is palatable and can promote similar increases in physical capacity as MICT, despite less than half the time commitment and training volume, means that clinical rehabilitation specialists can now offer a new, more time-efficient, exercise training strategy to elicit improvements in their patients.