In this study we investigated metabolic power during whole-body vibration exercise (VbX) compared to mild resistance exercise. Specific oxygen consumption (VO2) and subjectively perceived exertion (rating of perceived exertion, RPE; Borg scale) were assessed in 12 young healthy subjects (8 female and 4 male). The outcome parameters were assessed during the last minute of a 3-min exercise bout, which consisted of either (1) simple standing, (2) squatting in cycles of 6 s to 90 degrees knee flexion, and (3) squatting as before with an additional load of 40% of the subject's body weight (35% in females). Exercise types 1-3 were performed with (VbX+) and without (VbX-) platform vibration at a frequency of 26 Hz and an amplitude of 6 mm. Compared to the VbX- condition, the specific VO2 was increased with vibration by 4.5 ml x min(-1) x kg(-1). Likewise, squatting and the additional load were factors that further increased VO2. Corresponding changes were observed in RPE. There was a correlation between VbX- and VbX+ values for exercise types 1-3 (r = 0.90). The correlation coefficient between squat/no-squat values (r = 0.70 without and r = 0.71 with the additional load) was significantly lower than that for VbX-/VbX+. Variation in specific VO2 was significantly higher in the squatting paradigm than with vibration. It is concluded that the increased metabolic power observed in association with VbX is due to muscular activity. It is likely that this muscular activity is easier to control between individuals than is simple squatting.