Metabolic costs and rating of perceived exertion during backward walking in water and on dry land.

The purpose of this study was to compare metabolic costs, rating of perceived exertion (RPE), and stride frequency during backward walking in water and on land. The walking speeds in water were set to be half of those on land. There was no significant difference in metabolic costs and RPE between backward walking in water with a current and on land, at slow and moderate speeds (P > 0.05). However, at the fast speed (i.e., 3.0 and 6.0 km · h(-1) for water and land, respectively), the metabolic costs and RPE during backward walking on land were significantly higher than when walking backward in water with a current (P < 0.05). With regard to backward walking at faster speeds, if the walking speed in water with a current is set at half the speed on land, then the speed will be inadequate for inducing metabolic costs and RPE that are similar to those produced on land.

Physiological responses, rating of perceived exertion, and stride characteristics during walking on dry land and walking in water, both with and without a water current.

CONTEXT: Walking in water has been included in rehabilitation programs. However, there is a dearth of information regarding the influence of a water current on physiological responses, rating of perceived exertion (RPE), and stride characteristics of subjects while they walk in water. OBJECTIVE: To compare physiological responses, RPE, and stride characteristics of subjects walking in water (with and without a current) with those of subjects walking on dry land. DESIGN: Repeated measures. SETTING: University laboratory. PARTICIPANTS: 7 male adults (mean age = 21.6 y). INTERVENTION: Subjects walked on a treadmill on dry land and on an underwater treadmill immersed to the level of the xiphoid process. The walking speeds in water were set to be half of that on dry land. MAIN OUTCOME MEASURES: Oxygen consumption (VO2), respiratory-exchange ratio (RER), heart rate (HR), minute ventilation (VE), RPE (for breathing and legs, RPE-Br and RPE-Legs, respectively), systolic (SBP) and diastolic (DBP) blood pressures, and stride frequency (SF) were measured. In addition, stride length (SL) was calculated. RESULTS: There was no significant difference in the VO2, RER, HR, VE, RPE-Br, and RPE-Legs while walking in water with a current compared with walking on dry land (P > .05). Furthermore, VO2, RER, HR, VE, RPE-Br, RPE-Legs, SF, and SBP while walking in water were significantly higher with a water current than without (P < .05). CONCLUSIONS: These observations suggest that half the speed should be required to work at the similar metabolic costs and RPE while walking in water with a current, compared with walking on dry land. Furthermore, it was suggested that the physiological responses and RPE would be higher while walking in water with a current than without.

Physiological and perceptual responses to backward and forward treadmill walking in water.

We compared physiological and perceptual responses, and stride characteristics while walking backward in water with those of walking forward in water. Eight males walked on an underwater treadmill, immersed to their xiphoid process level. Oxygen uptake ((.)V(O2)), respiratory exchange ratio (R), heart rate (HR), minute ventilation ((.)V(E)), blood lactate concentration (BLa), ratings of perceived exertion (RPE: for breathing and legs, RPE-Br and RPE-Legs, respectively), blood pressure (for systolic and diastolic pressures, SBP and DBP, respectively), and step frequency (SF) were measured. In addition, step length (SL) was calculated. (.)V(O2), R, HR, V (E), BLa, RPE-Br, RPE-Legs, and SBP were significantly higher while walking backward in water than when walking forward in water (P<0.05). Furthermore, SF was significantly higher (P<0.001) and SL was significantly lower (P<0.001) while walking backward in water, compared to walking forward in water. These results indicate that walking backward in water elicits higher physiological and perceptual responses than those produced when walking forward in water at the same speed.