A comparative study of two protocols for treadmill walking exercise testing in ambulating subjects with incomplete spinal cord injury

Abstract

Study design: This is a comparative study of two exercise testing protocols.

Objectives: The objective of this study was to compare maximal oxygen uptake (VO₂ max) and achieved criteria for maximal exercise testing between the Sunnaas Protocol-a newly designed treadmill exercise test protocol-and the Modified Bruce Protocol in persons with incomplete spinal cord injury (SCI).

Setting: This study was conducted in Sunnaas Rehabilitation Hospital, Norway.

Methods: Twenty persons (19 men) with incomplete SCI (AIS D) capable of ambulating without assistive devices performed two treadmill walking exercise tests (Sunnaas Protocol and Modified Bruce Protocol) until exhaustion 1-3 days apart. The key differences between the protocols are the smaller increments in speed and shorter duration on each workload in the Sunnaas Protocol. Cardiovascular responses were measured continuously throughout both tests.

Results: The subjects exhibited statistically significantly higher VO₂ max when using the Sunnaas Protocol (37.1±9.9 vs 35.4±9.8 ml kg^-1 min^-1, P=0.01), with a mean between-test difference of 1.8 ml kg^-1 min^-1 (95% confidence interval: 0.49-3.16). There was no significant difference in mean maximal heart rate (HR max). Nineteen (95%) subjects achieved at least three of the four criteria for maximal oxygen uptake using the Sunnaas Protocol. Thirteen (65%) subjects achieved at least three of the criteria using a Modified Bruce protocol.

Conclusions: The small differences in both VO₂ max and achieved criteria in favor of the Sunnaas Protocol suggest that it could be a useful alternative treadmill exercise test protocol for ambulating persons with incomplete SCI.