Running Barefoot Reduces Stress—On Feet

Going barefoot isn't just for strolling on the beach: Running barefoot reduces stresses on your feet and may prevent injuries known to afflict traditionally shod runners, a new study says.

In his bestselling book Born to Run, Christopher McDougal revealed that the best long-distance runners on the planet may be Mexico's Tarahumara Indians, who race barefoot or in thin sandals through the remote Copper Canyons of Chihuahua state.

The new study used high-speed video and a bathroom scale-like device called a force plate to digitally dissect the moment-by-moment stresses on the feet of 63 runners as they ran barefoot.

The research revealed that running barefoot changes the way a person's feet hit the ground.

Runners in shoes tend to land on their heels, so sports shoe makers have spent years designing footwear with gels, foams, or air pockets in the heels to reduce the shock of impact.

But barefoot runners more often land on the forefoot, near the base of the toes. This causes a smaller part of the foot to come to a sudden stop when the foot first lands, allowing the natural spring-like motion of the foot and leg to absorb any further shock.

"This form of landing causes almost no collision force," lead author Daniel Lieberman, an evolutionary biologist at Harvard University, said in an email.

Not that the benefits of barefoot running should be a surprise, he added: "Humans were able to run for millions of years without shoes or in just sandals."

The work, published online today by the journal Nature, is "really interesting and useful," according to coach, exercise physiologist, and author Jack Daniels.

"There is no doubt impact is a major source of injury," Daniels said via email, and reducing injuries is a key goal of all runners and coaches.

Daniels himself has done much of his own running barefoot.

"I eventually got to where I could go barefooted for five miles [eight kilometers] on a concrete sidewalk," he said, though he admits he prefers grass and well-cushioned tracks.

Even the latter, he added, takes practice.

"One main problem is the abrasion factor," he said. "You have to toughen up the skin on the bottom of your feet."

Luckily the choice won't be between shoes or no shoes for long. Shoe companies have been scrambling to design "minimalist" footwear that still protects the feet from rocks, thorns, and broken glass while allowing people to run more naturally.

"If you start with a thick shoe and slowly whittle down, at what point does the person start to run like they're barefoot?" pondered Sean Murphy, manager of advanced products engineering and sports research for shoe maker New Balance.

"We've completed those studies and come up with some pretty solid lines of thinking on how you make the foot work as naturally as possible and at the same time protect [it] from the elements," Murphy said.

"I'm pretty confident you're gong to see more and more products in that vein."

Save the Ozone Layer, Give Global Warming a Boost?

While most of the world has warmed, parts of the southern hemisphere have remained stubbornly cold—oddly enough because of a gaping hole in the ozone layer. Now new research shows that all the efforts made by scientists and environmental advocates to close the hole may actually increase warming throughout the entire southern hemisphere.

That's because, for decades, brighter summertime clouds, created by the hole, have reflected more of the sun's rays, acting as a shield against global warming.

As the ozone layer heals and the clouds dissipate, this “will lead to a rise in temperature [in parts of the southern hemisphere] faster than currently predicted by models," said study leader Ken Carslaw of the U.K.'s University of Leeds.

In 1985 scientists from the British Antarctic Survey discovered a giant hole in theozone layer in the upper atmosphere over Antarctica. Ozone in the upper atmosphere absorbs harmful ultraviolet rays from the sun.

The subsequent global agreement to ban chlorofluorocarbons (CFCs)—the chemicals largely responsible for the thinning of the ozone layer—reversed the growth of the ozone hole and was deemed one of the biggest environmental success stories of the 20th century.

But the healing process is slow: Since the early 1980s changes in the upper atmosphere caused by ozone depletion have intensified circumpolar winds that whistle around Antarctica.

Using a computer model and two decades worth of meteorological data, Carslaw and colleagues discovered that the fiercer winds whip up more sea spray. This throws more salt particles into the air and encourages the formation of brighter clouds, which reflect sunlight back into space and have a cooling effect.

The summertime cooling caused by the ozone hole since 1980 has approximately cancelled out the warming caused by rising carbon dioxide emissions, Carslaw said.

Superlungs Gave Dinosaurs Competitive Edge?

Dinosaurs' superior lungs may have allowed them to outcompete early mammals, according to a new study of modern-day alligators.

Scientists found that a method of high-efficiency breathing used by birds is also employed by today's alligators, which share a common ancestor with dinosaurs.

In mammals, each fresh breath carries oxygen-rich air to "cul-de-sacs" in the lungs called alveoli.

Air circulating through these sacs transfers oxygen into the bloodstream that picks up the blood's carbon dioxide waste.

But birds don't have alveoli. Instead, the air flows in one direction into the birds' air sacs.

This adaptation keeps birds' lungs filled with "fresh" air, allowing them to breathe at altitudes that would kill other animals.

To find out how alligators breathe, scientists pumped fluids through the lungs of dead American alligators and measured the direction of the resulting airflow.

The team found that, similar to birds, air bypasses certain tiers of bronchi, or airways--only to flow back through those bronchi before being exhaled.

Such a pattern likely arose in the common ancestor of birds, dinosaurs, and alligators--called archosaurs--during the Triassic period, 251 to 199 million years ago.

During the Early Triassic Period, the atmosphere was lower in oxygen than it is today.

"We know that in birds this lung structure is part of the reason birds are good at exercising in rarefied air," said study leader C.G. Farmer, an evolutionary biologist at the University of Utah.

"Our data suggest the archosaurs had a competitive edge in their low-oxygen world."

Dinosaurs' high level of fitness could also explain why mammals remained so small until the mass extinction of the dinosaurs 65 million years ago.

"It's as though these animals were being repressed, or kept small, by the archosaurs."

Male Fish Punish Unruly Females -- And Benefit, Study Says

Cheaters may not prosper—but punishers do, according to a new study.

Male cleaner fish will chase and pester female fish if they interfere with the male's mealtime—the first evidence of a species benefiting from third-party punishment.

If you're a cleaner fish, it's bad table manners to nibble on the mucous layer of "client" fish, which are generally bigger than the cleaners. Clients stop by multifish cleaning "stations" to get rid of their parasites, which become food for the cleaners.


But biting off a chunk of tasty mucous means the larger fish may flee—so one mischievous cleaner can deprive another from a meal.

The male "loses something if the female cheats the client, and that's why he corrects the behavior," said study co-author Redouan Bshary, a behavioral ecologist at Switzerland's Université de Neuchâtel.

Not that males are always respectable: They'll cheat, too, but females endure most of the punishment simply because they're weaker, he added.

"Imagine you are collaborating with Mike Tyson," Bshary said. "If you cheat he will punish you, but if he cheats you probably won't do anything." 


Scientists had observed male cleaner fish chasing mucous-eating females in the wild.

But to determine if the males were punishing females, Bshary and colleagues created an experiment. They provided aquarium-dwelling bluestreak cleaner wrasse with a plate of fish flakes—their boring, everyday diet—and prawns, which are about as delectable as fish mucous. (See a wrasse picture.)

Each time a female ate a prawn, scientists removed all the food from the tank.

The team observed that the males chastised prawn-eating females—and that the females obeyed by stopping the behavior.

The study, published today in Science, "is really the first to show a direct benefit to the individual who does the punishing," according to Sarah Brosnan, a behavioral scientist at Georgia State University.

The discovery also offers a "potential explanation for how [punishing] might have evolved in other organisms as well—but this may not hold for other types of social [animals]," added Brosnan, who was not involved in the research.

For example most human studies of third-party punishment show that—unlike in cleaner fish—the individual doesn't benefit, according to Peter Richerson, an expert in human cultural evolution at the University of California, Davis.

Though controversial, some scientists say these experiments show that human do-gooders evolved to benefit the group, rather than the individual, Richerson said.

But he doesn't think the cleaner fish study will lend much insight into human behavior.

"No such issue arises in the [fish] experiment because the males benefit directly from punishing defector females."