Cardiovascular and Stride Frequency Differences During Land and Aquatic Treadmill Walking

This study examined heart rate (HR) and stride frequency (SF) values of 30 college-aged males and females during dry-land (DL) and aquatic walking (AW). Aquatic walking trials were completed in an underwater treadmill with the water depth at waist level; the water temperature (31℃ ± 0.1℃) and room temperature (26.6℃ ± 0.1℃) were maintained at thermoneutral levels throughout the study. During each walking condition, HR and SF were recorded at treadmill speeds of 1 mph, 2 mph, and 3 mph. Participants were instructed to walk with their hands at their sides swinging as they would when walking on dry-land unless they felt the need to use the handrails to steady themselves. Heart rate monitors were used to record cardiovascular changes, and strides were measured from consecutive left and right toe strikes. Results of the study indicated HR was significantly higher during DL than AW at 1 mph ( p < .001) and 3 mph ( p < .001) but was not significantly different ( p = .64) at 2 mph. The SF of the participants was significantly lower ( p < .001) during AW than DL at all speeds. When comparing sex, females had significantly higher HR at 1 mph ( p = .012), 2 mph ( p = .007), and 3 mph ( p < .001) than males for DL conditions. No differences in HR were found during the AW conditions ( F = 0.66, p = 0.44, η p2 = 0.02). No differences in SF were observed between males and females in both DL ( F = 2.96, p = 0.06, η p2 = 0.09) and AW ( F = 1.03, p = 0.32, η p2 = 0.036) conditions. As a result, AW increased HR values similar to those of DL, but without the added stress to the lower extremities due to the buoyancy of the water. Thus, AW provided an exercise medium capable of meeting the ACSM intensity guidelines for PA and allowed adults to be physically active presumably with less stress on the lower body.