Pohl (2003) The physiological responses to running and walking in water at different dephts

Exercise in an aquatic environment may be an effective mode of therapy andtraining due to reduced impact forces. The purpose of this study was to comparethe physiological responses of walking/running on a land treadmill withwater treadmill responses at two different depths. Six subjects completedwalking and running trials on both a land-based and a water-based treadmill.Water-based trials were completed in both thigh- and waist-deep water.Each trial was five minutes in duration. Oxygen uptake (VO2), heart rate (HR),respiratory exchange ratio (RER), stride frequency (SF), and the oxygen costper stride (VO2/stride) were compared between the conditions using a twowayANOVA with repeated measures. Walking and running in water elevatedVO2 (p < 0.02) and HR (p < 0.04) above land treadmill values. When runningin waist-deep water, VO2 and HR failed to increase to the same extent asthigh-deep running. Stride frequency was similar between the three differentdepths during walking but lower in waist-deep water during running. VO2/stride was significantly higher (p < 0.01) in water-based walking and runningcompared to land-based values. Water-based walking and running eliciteda greater physiological cost than land-based exercise, which can be attributedto the elevated cost of moving in water due to increased resistance.When running in waist-deep water, buoyancy may counter the resistance ofthe water and serve to lower the physiological cost of locomotion.

 

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