At-Home High-Intensity Interval Training for Individuals with Paraplegia Following Spinal Cord Injury: A Case Series

Figure 1.. At-home high-intensity interval training (HIIT) study design. A) Schematic depicting an example of an at-home HIIT session. The target exercise intensity (% of heart rate reserve) is depicted for one-minute bouts of high intensity followed by two minutes of recovery. B) Representative figure of participant heart rate data during an at-home HIIT session obtained from the Polar phone application. The shaded grey-area depicts the target heart rate zone corresponding to a value at or above ~80% HRR. C) Schematic of the participant equipment provided for at-home HIIT. Participants were given an arm cycle, hydraulic table, and Polar heart rate strap to provide visual feed-back and instruction to achieve target exercise intensity during the training sessions. The participant’s phone was mounted to the hydraulic table to allow for visual heart rate feedback.

Figure 2.. Line plots depicting individual participant heart rate data achieved during the at-home high-intensity interval training (HIIT sessions. The solid line depicts the average heart rate across all completed HIIT sessions, and the grey bands depict the standard deviation. The top dashed line represents the prescribed high-intensity target of 80% heart rate reserve (HRR), the middle-dashed line represents the acceptable high-intensity threshold of 70% HRR, and bottom dashed line represents the recovery target of 30% HRR. Abbreviations: M: Male; F: Female; T: Thoracic; HRR: Heart Rate Reserve.

Figure 3.. Line plot depicting the composite high-intensity interval training (HIIT) session data for all participants across all attempted workouts (n=338). Data is normalized to the percent of heart rate reserve (HRR). The solid black line depicts the average heart rate, and the grey bands depict the standard deviation. Dashed lines at 70 and 80% HRR represent acceptable and target HRR for each interval, respectively, and the dashed line at 30% HRR represents the recovery target.

Figure 4.. Scatter plot depicting the comparison of age-predicted maximal heart rate versus the measured maximal heart rate during a graded exercise test using arm ergometry. The solid line represents the line of identity and dashed line represents line of best fit. Solid symbols indicate male data and open symbols indicate female data.