Objective: The aim of this study was to (1) compare the peak oxygen uptake across three protocols of different duration during an incremental deep water running test to exhaustion; (2) study the reproducibility of peak Vo2 during two repeated incremental deep water running tests; (3) compare peak deep water running test and treadmill cardiopulmonary responses in adults older than 45 yrs.
Design: First, 24 healthy subjects older than 45 yrs (60 yrs [6 yrs], body mass index: 28 kg/m [6 kg/m], 11 men/13 women) performed three incremental deep water running tests (< or =8 mins, 8-12 mins, and > or =12 mins) with measurement of peak Vo2 (optimization group). Nineteen subjects of the 24 original subjects (reproducibility group) then performed two repeated maximal deep water running tests. Finally, 21 of the 24 original subjects also performed an additional maximal treadmill test (comparison group). Peak Vo2 was compared with analyses of variance for repeated measurements for the optimization, reproducibility, and comparison groups.
Results: Peak Vo2 (ml/min) did not differ according to protocol duration (short: 1529 [674]; intermediate, 1456 [594]; and long, 1465 [674] ml/min, P = 0.53), was reproducible with an intraclass correlation coefficient of 0.90 (P < 0.0001), and was lower compared with treadmill (deep water running test: 1615 [586] vs. T: 2545 [511] ml/min, P < 0.0001).
Conclusions: A 6- to 12-min protocol duration can be used to assess deep water running test peak Vo2, which is reproducible and lower compared with that obtained on the treadmill in healthy subjects older than 45 yrs.