Physiological strain to prolonged exercise bouts at the walk-run transition speeds depends on locomotion mode in healthy untrained men.

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±5.01years; height: 174.0 ±0.3cm; body mass: 74.5±0.6kg) 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±0.06km/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=0.26L/min; pulmonary ventilation: mean difference=5.53L/min; carbon dioxide output: mean difference=0.32L/min; heart rate: mean difference=13 beats/min; total energy expenditure: mean difference=59kcal). 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.