Energy costs of walking on a dual-action treadmill in men and women.

The physiological responses of normal walking and walking on a dual action treadmill which incorporates arm exercise were compared in 29 men and 37 women. Subjects completed six, 5-min steady-state exercises at 2.0, 3.0, and 4.0 mph (0.89, 1.34, 1.79 m.s-1) and 3% incline with and without arms. Estimated METs calculated according to the ACSM equations were compared with the actual METs. The men's ventilation (VE), and VO2 (l.min-1, ml.kg-1.min-1, and METs) were significantly (P < 0.001) higher at all speeds and for both conditions than the women's. There were no gender differences (P > 0.05) in heart rates (HR), respiratory exchange ratio, and ratings of perceived exertion (RPE) for each condition. The arm conditions yielded significantly (P < 0.001) higher responses at each speed for VE, l.min-1, ml.kg-1.min-1, METs, RPE, and HR. Although there were no significant (P < 0.05) differences in HR between men and women for each condition, the relationships between ml.kg-1.min-1 and HR differed. The actual METs obtained during the arm conditions were significantly (P < 0.05) higher than those estimated for both the men and women at all speeds. It was concluded that using the arms while walking on a dual action treadmill increases the energy costs an average of 55% above normal walking.