Comparison of peak cardiopulmonary performance parameters during robotics-assisted treadmill exercise and arm crank ergometry in incomplete spinal cord injury.

Objective: (i) to compare cardiopulmonary performance parameters obtained from incremental exercise tests (IETs) performed using a robotics-assisted treadmill and an arm crank ergometer; (ii) to investigate test-retest reliability during both modes of exercise.

Design: Each participant performed two IETs to the limit of tolerance on both a robotics-assisted treadmill and an arm crank ergometer.

Setting: A Spinal Injuries Unit in the United Kingdom.

Participants: 10 people with an incomplete spinal cord injury (SCI).

Interventions: Not applicable.

Main Outcome Measures: Peak oxygen uptake (VO(2peak)), the gas exchange threshold (GET), peak heart rate (HR(peak)) and peak lactate (Lactate(peak) were obtained for each mode of assessment. The mean responses and test-retest reliability of the main outcome measures were determined and compared between modes of assessment.

Results: VO(2peak) was 16% higher (p = 0.016) and the VO2 at the GET was 40% higher (p = 0.007) during the robotics-assisted treadmill exercise (RATE) IET. There was a trend for HR(peak) to be higher during arm crank ergometry (ACE) (p = 0.058). Lactate(peak) was 46% higher (p = 0.006) during the ACE IET. During robotics-assisted exercise, the test-retest reliability was very high for VO2(peak) (r = 0.95), high for the GET (r = 0.75) and HR(peak) (r = 0.88), and moderate for Lactate(peak) (r =0.58). For ACE, the test-retest reliability was very high for VO(2peak) (r = 0.93), high for HR(peak) (r = 0.81) and Lactate(peak) (r = 0.78), and low for the GET (r = 0.16).

Conclusions: The results suggest that, when compared with ACE,RATE can be a highly effective stressor of the cardiopulmonary system, and may be a more appropriate mode of assessment to determine and monitor cardiopulmonary fitness in people with incomplete SCI.