Physiological responses during an incremental exercise test performed on underwater stationary bike

Purpose Cycling underwater is a low impact physical activity that has became popular workout due to capability to enhance physical fitness. The aim of this study was to determine the relationship between pedal cadence with heart rate (HR) and oxygen uptake ( V O 2 ) during incremental exercise test in a novel adjustable resistance bike underwater. Methods Fifteen participants completed three incremental cycling tests in a random order. Each test began at 50 revolutions per minute (RPM) and increased 3 RPM every minute until volitional exhaustion. The bike has the unique ability to manipulate the frontal surface area (FSA) of the blades providing three different resistance settings for the same RPM (FSA 1 = 500 cm 2 , FSA 2 = 580 cm 2 , and FSA 3 = 660 cm 2 ). Results The findings indicated a strong linear relationship between RPM vs. % V O 2peak and RPM vs. %HR peak in all FSA conditions ( r = 0.98–0.99). In addition, the results showed a significant lower peak cadence for the FSA3 setting compared to the other conditions ( p