ABSTRACT
This study compared the physiological strain induced by prolonged walking and running performed at the walk-run transition speed (WRTS) in healthy untrained men. Twenty volunteers (age: 28 ± 5.01 years; height: 174.0 ± 0.3 cm; body mass: 74.5 ± 0.6 kg) underwent the following: (a) ramp-incremental maximal cardiopulmonary exercise test (CPET); (b) specific protocol to detect the WRTS; and (c) two 30-min walking and running bouts at WRTS (mean ± SD: 6.9 ± 0.06 km/h). Expired gases were collected during exercise bouts via the metabolic cart. A significant effect of locomotion mode (F = 4.8, P < 0.001) was observed with running resulting in higher cardiorespiratory responses than walking at the WRTS (oxygen uptake: mean difference = 0.26 L/min; pulmonary ventilation: mean difference = 5.53 L/min; carbon dioxide output: mean difference = 0.32 L/min; heart rate: mean difference = 13 beats/min; total energy expenditure: mean difference = 59 kcal). The rating of perceived exertion was similar across locomotion modes (mean difference = 0.3; P = 0.490). In conclusion, running promoted greater cardiorespiratory responses than walking at the WRTS in untrained healthy men. These data might have practical impact on aerobic training performed at intensities corresponding to WRTS.
