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

Abstract

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 (V̇O_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:

V̇O_2peak was 16% higher (p= 0.016) and the V̇O₂ 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 V̇O_2peak (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 V̇O_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.