Abstract
Background and Purpose: People with spinal cord injury (SCI) experience secondary complications including low levels of cardiometabolic activity and associated health risks. It is unknown whether overground bionic ambulation (OBA) enhances cardiometabolic challenge during walking in those with motor-incomplete SCI, thereby providing additional therapeutic benefits.
Case Descriptions: One man and one woman with chronic motor-incomplete paraplegia due to SCI.
Intervention: Assessment of functional walking capacity with the 10-m and 6-minute walk tests. Participants underwent cardiometabolic measurements including heart rate (HR), oxygen consumption (
O2), energy expenditure (EE), and substrate utilization patterns during OBA and overground walking for 6 minutes each.
Outcomes: The female participant had low functional walking capacity (walking speed = 0.23 m/s; 6-minute walk = 230 ft). She had higher cardiorespiratory responses during OBA versus overground walking ([DELTA]
O2 = -3.6 mL/kg/min, [DELTA]EE = 12 kcal) despite similar mean HR values ([DELTA]HR = -1 beats per minute). She was able to sustain continuous walking only during the OBA trial. The male participant had greater walking capacity (walking speed = 0.33 m/s, 6 minutes = 386ft) and lower responses during OBA versus overground walking ([DELTA]
O2 = -6.0 mL/kg/min, [DELTA]EE = -18 kcal, [DELTA]HR = -6 beats per minute). He was able to walk continuously in both conditions.
Discussion: The participant with lower walking capacity experienced a higher cardiometabolic challenge and was able to sustain exercise efforts for longer period with OBA versus overground walking. Therefore, OBA presents a superior alternative to overground training for cardiometabolic conditioning and associated health benefits in this participant. For the participant with higher walking capacity, OBA represented a lower challenge and appears to be an inferior cardiometabolic training option to overground walking. The cardiometabolic response to OBA differs depending on functional capacity; OBA warrants study as an approach to cardiometabolic training for individuals with motor-incomplete SCI who have limited lower extremity function.
Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A259).