Reliability of treadmill exercise testing in older patients with chronic hemiparetic stroke

Objective: To assess the test-retest reliability of cardiopulmonary measurements during peak effort and submaximal treadmill walking tests in older patients with gait-impaired chronic hemiparetic stroke. Design: Nonrandomized test-retest. Setting: Hospital geriatric research stress testing laboratory. Participants: Fifty-three subjects (44 men, 9 women; mean age, 65+/-8y) with chronic hemiparetic gait after remote (>6mo) ischemic stroke. Patients had mild to moderate chronic hemiparetic gait deficits, making handrail support necessary during treadmill walking. Interventions: Peak effort and submaximal effort treadmill walking tests were conducted and then repeated on a separate day at least a week later. Main Outcome Measures: Reliability coefficients (r) were calculated for heart rate, systolic blood pressure (SBP), oxygen consumption (VO2 [L/min]), VO2 (mL.kg(-1).min(-1)), respiratory exchange ratio (RER), rate-pressure product (RPP), and oxygen pulse during peak effort testing. The reliability coefficients for all but SBP and RPP data were calculated from the submaximal tests. Results: Heart rate (r=.87), VO(2)peak (L/min) (r=.92), VO(2)peak (mL.kg(-1).min(-1)) (r=.92), and oxygen pulse (r=93) were highly reliable parameters during maximal testing in this population. Submaximal testing produced highly reliable results for (V) over dotO(2) (L/min) (r=.89) and oxygen pulse (r=.85). All cardiopulmonary measures except RER had a reliability coefficient greater than .80 during submaximal testing in this population. Conclusion: Our study provides the first evidence that peak effort treadmill testing provides highly reliable oxygen consumption measures in chronic hemiparetic stroke patients using minimal handrail support. The submaximal tests were at or near the threshold level of reliability for the 2 most important measures of (V) over dotO(2) (L/min) and (V) over dotO(2) (mL.kg(-1).min(-1)) (r=.89, r=.84, respectively), with the remaining measures falling above .70.