A widespread assumption of previous researchers is that the gait transition during human locomotion takes place at speeds that minimize metabolic energy consumption. The primary purpose of this investigation was to determine, by direct measurements, whether changing gaits is actually an energy saving mechanism. The secondary purpose of the experiment was determine whether the sense of effort, as measured by a Rating of Perceived Exertion (RPE), was greater for walking or running at the preferred transition speed (PTS). Twenty young, healthy adults (10 males, 10 females) walked on a treadmill at five speeds ranging from 70-110% of their individually measured PTS, and ran at five speeds ranging from 90-130% of their PTS while VO2 was monitored to determine each individual's energetically optimal transition speed (EOTS). Although the EOTS found during this study (2.24 m.s-1) was significantly greater than the PTS (2.06 m.s-1), RPE was significantly greater while walking at the PTS (13.5) than running at the PTS (10.0), suggesting that the gait transition during human locomotion does not take place in order to minimize metabolic energy consumption.