"each person has an optimal running pace that uses the least amount of oxygen to cover a given distance." = diving O2 efficiency/conservation. Savannah animals either walk (efficient O2 consumption per meter) or run short distances at a unsustainable higher speed (inefficient O2 consumption, overheating). (Not referring to top-speed anaerobic sprints, just moderate aerobic running. Athletic humans can run along shores (abundant water, salt electrolytes) for very long distances without rest, athletic horses can't run for very long distances).
Perfect Running Pace Revealed
http://news.yahoo.com/s/livescience/20090329/sc_livescience/perfectrunningpacerevealed
Dan Peterson
LiveScience's Sports Columnist
LiveScience.com dan Peterson
livescience's Sports Columnist
livescience.com – Sun Mar 29, 10:15 am ET
Most regular runners can tell you when they reach that perfect equilibrium of speed and comfort. The legs are loose, the heart is pumping and it feels like you could run at this pace forever.
Researchers at the University of Wisconsin-Madison now have an explanation for this state of running nirvana, and we can thank our ancestors and some evolutionary biology for it.
For years, it has been thought that humans have a constant metabolic energy rate. It was assumed that you would require the same total energy to run one mile, no matter if you ran it in 5 minutes or 10 minutes. Even though your energy burn rate would be higher at faster speeds, you would get there in half the time.
Turns out, however, that each person has an optimal running pace that uses the least amount of oxygen to cover a given distance. The findings, by Karen Steudel, a zoology professor at Wisconsin, and Cara Wall-Scheffler of Seattle
Pacific University, are detailed in latest online edition of the Journal of Human Evolution.
Steudel's team tested both male and female runners at six different speeds on a treadmill while measuring their oxygen intake and carbon dioxide output. As expected, each runner had different levels of fitness and oxygen use but there
were ideal speeds for each runner that required the least amount of energy.
Overall, the optimal speeds for the group were about 8.3 mph (13.4kph) (about a 7:13 minutes per mile) for males and 6.5 mph (9:08 min/mile) for females.
The most interesting finding: At slower speeds, about 4.5 mph (13 min/mile), the metabolic efficiency was at its lowest. Steudel explains that at this speed, halfway between a walk and a jog, the runner's gait can be awkward and unnatural.
"What that means is that there is an optimal speed that will get you there the cheapest," Steudel says.
So, why is a zoology professor studying running efficiency? Steudel's previous work has tried to build a theory of why our early ancestors evolved from moving on four limbs to two limbs, also known as bipedalism. She has found that human walking is a more efficient method of getting from point A to point B than on all fours. It might also have been an advantage for hunting.
[When chimpanzees hunt, they chase antelope or monkeys while on all fours (quadrupedal) and bite their prey with their large canine teeth, but when spearing small primates in tree hollows (not chasing, just probing and stabbing downwards), they tend to maintain an upright posture. Savanna chimps may walk bipedal briefly (especially when crossing shallow water), but do not run bipedally, nor run quadrupedally long distances, and of course, cannot swim or dive. Although I haven't found specific evidence, it seems they cannot hold their breath except briefly.]
