Ohio State University (Ohio, USA) researchers submit that the human body has an innate sense of how to vary speed to optimize energy when it is on the move in the natural environment. As many exercise efficiency studies are conducted on treadmills, they do not necessarily reflect real-world situations as to energy expenditure and endurance preservation. Manoj Srinivasan and colleagues enrolled 36 college students were asked to travel a distance longer than a football field, either on pavement outdoors or inside a school hallway. Each was given a stopwatch, and told to arrive at the destination specific time, not before and not after – but exactly on-time. Subjects were not told whether to walk or run, and could set their own pace. The team instructed for the subjects to complete two extreme trips: at one extreme, the subjects were told to make the trip in 2 minutes – so they could do so at a leisurely pace if they chose; at the other extreme, they were allotted only 30 seconds, so they had to run at a very brisk pace. The team was most interested in what the subjects would do when they were allotted travel times between the two extremes, finding that a transition region existed where the subjects mixed the trip between walking and running. Regardless of any variable – fitness level, height, weight, leg length, amount of time given for the trip, whether they were indoors or out – all subjects employed a mixture of walking and running. The team observed that the subjects seem to naturally break into a run, or slow down to a walk, to save energy while ensuring they arrived at the destination on time. The study authors conclude that: ” Humans and other animals might also benefit energetically from alternating between moving forward and standing still on a slow and sufficiently long treadmill.”
