Predicting peak oxygen uptake from submaximal exercise after spinal cord injury

The purpose of this study was to determine the validity of the 6-min arm ergometry test (6MAT) in predicting peak oxygen consumption ((V) over dotO(2peak)) in individuals with chronic spinal cord injury (SCI). Fifty-two individuals with chronic SCI (age, 38 +/- 10 years; American Spinal Injury Association Impairment Scale (AIS), A-D; neurological level of injury (NLI), C1-L2; years post-injury (YPI), 13 +/- 10 years) completed an incremental arm ergometry (V) over dotO(2peak) test and a submaximal 6MAT. Oxygen consumption ((V) over dotO(2)) data from both tests were used to create a predictive equation with regression analysis. Subsequently, a cross-validation group comprising an additional 10 individuals with SCI (age, 39 +/- 13 years; AIS, A-D; NLI, C3-L3; YPI, 9 +/- 9 years) were used to determine the predictive power of the equation. All participants were able to complete both the (V) over dotO(2peak) and 6MAT assessments. Regression analysis yielded the following equation to predict (V) over dotO(2peak) from end-stage 6MAT (V) over dotO(2): (V) over dotO(2peak) (mL.kg(-1).min(-1)) = 1.501(6MAT (V) over dotO(2)) - 0.940. Correlation between measured and predicted (V) over dotO(2peak) was excellent (r = 0.89). No significant difference was found between measured (17.41 +/- 7.44 mL.kg(-1).min(-1)) and predicted (17.42 +/- 6.61 mL.kg(-1).min(-1)) (V) over dotO(2peak) (p = 0.97). When cross-validated with a sample of 10 individuals with SCI, correlation between measured and predicted (V) over dotO(2peak) remained high (r = 0.89), with no differences between measured (18.81 +/- 8.35 mL.kg(-1).min(-1)) and predicted (18.73 +/- 7.27 mL.kg(-1).min(-1)) (V) over dotO(2peak) (p = 0.75). Results suggest that 6MAT (V) over dotO(2) can be used to predict (V) over dotO(2peak) among individuals with chronic SCI. The 6MAT should be used as a clinical tool for assessing aerobic capacity when peak exercise testing is not feasible.