Reliability and Validity of a Deep Water Running Graded Exercise Test

To examine the reliability for peak responses of oxygen consumption (VO_2peak) in relative (ml · kg^-1 · min^-1) and absolute (L/min^-1) measures, as well as peak heart rate (HR_peak) during deep water running (DWR), 26 participants (12 women, 14 men) completed two DWR maximal graded exercise tests. To estimate the validity of the peak responses during DWR, a comparison to a treadmill running (TMR) graded exercise test (GXT) was completed. Test order was randomized. The DWR GXT utilized a system of weights and pulleys to increase intensity of exercise. Reliability of the DWR test for the total group was estimated using a repeated measures one-way analysis of variance (ANOVA) for VO_2peak (ml · kg^-1 · min^-1, R = .96; L/min^-1, R = .97) and HR_peak (R = .90). There were no significant differences (p > .05) between the two DWR tests for men or women for the means of VO_2peak in relative units (men: 50.5 vs. 52.0 ml · kg^-1 · min^-1; women: 37.1 vs. 36.8 ml · kg^-1 · min^-1), or absolute units (men: 4.1 vs. 4.1 L/min^-1; women: 2.2 vs. 2.2 L/min^-1), or HR (men: 174 vs. 175 beats per minute (bpm); women: 181 vs. 183 bpm). There was a significant correlation between the average of the two DWR tests and TMR for the total group for VO_2peak for relative (r = .88, p = .001) and absolute (r = .93, p = .001) measures as well as HR_peak (r = .64, p = .001). Peak responses during the DWR protocol were judged to be reliable. Also, the correlation for the variables between DWR and TMR indicates a positive relation between peak responses. The correlation suggests validity of predicting TMR peak responses from DWR peak responses; however, this conclusion may be questionable due to the low sample size and the large systemic differences between tests. Finally, HR_peak and VO_2peak were lower during DWR than TMR for both men and women.