Two new studies suggest that modern running shoes could increase the risk of injuries to runners.

One study involved sixty-eight healthy young women and men who ran at least twenty-four kilometers a week. The runners were observed on a treadmill machine (跑步机). Sometimes they wore running shoes. Other times they ran barefoot.

Researchers from the JKM Technologies Company in Virginia, the University of Virginia and the University of Colorado did the study.

They found that running shoes create more stress that could damage knees, hips and ankle joints than running barefoot. They observed that the effect was even greater than the effect reported earlier for walking in high heels.

The study appeared in the official scientific journal of the American Academy of Physical Medicine.

The other study appeared in the journal Nature. It compared runners in the United States and Kenya. The researchers were from Harvard University in Massachusetts, Moi University in Kenya and the University of Glasgow in Scotland.

They divided the runners into three groups. One group had always run shoeless. Another group had always run with shoes. And the third group had changed to shoeless running.

Runners who wear shoes usually come down heel first. That puts great force on the back of the foot. But the study found that barefoot runners generally land on the front or middle of their foot. That way they ease into their landing and avoid striking their heel.

Harvard’s Daniel Lieberman led the study. He says the way most running shoes are designed may explain why those who wear them land on their heels. The heel of the shoe is bigger and heavier than other parts of the shoe, so it would seem more likely to come down first. Also, the heel generally has thick material under it to soften landings.

But the researchers do not suggest that runners immediately start running barefoot. They say it takes some training. And there can be risks, like running when your feet are too cold to feel if you get injured.

The study was partly supported by Vibram, which makes a kind of footwear that it says is like running barefoot. The findings have gotten a lot of attention. But the researchers say there are many problems in the way the press has reported in their paper. So they have tried to explain their findings on a Harvard Website.

What do babies, puppies and cartoon characters have in common? 【小题1】

Cute animals and babies attract our attention and make us want to take care of them, which gives them an evolutionary advantage, according to Austrian zoologist Konrad Lorenz.

【小题2】 When we look at babies, we are attracted to certain facial features. These features make us want to take care of them so they can grow up healthily and pass their genes on to the next generation.

Looking at baby animals and cartoon characters also cause these feelings. Childlike characteristics make babies sweet and lead us to build close ties with them. 【小题3】

There are several features that can cause this feeling. 【小题4】 If a baby animal or human wobbles a bit when walking, that can make them seem even cuter.

Of course, we don’t raise baby animals the same way we raise human babies, and we don’t raise cartoon characters at all. 【小题5】 Cute cartoon characters become popular this way, and baby animals are more likely to be cared for properly.

Think about some of the things that you find cute, and you’re likely to see that they have some of the same characteristics as a human baby.

People with less education suffer fewer stressful days, according to a report in the current issue of the Journal of Health and Social Behavior.       

However, the study also found that when less-educated people did suffer stress it was more severe and had a stronger effect on their health.

From this, researchers have concluded that the day-to-day factors that cause stress are regular. Where you are in society determines the kinds of problems that you have each day, and how well you will deal with them.

The research team interviewed a national sample of 1,031 adults daily for eight days about their stress level and health. People without a high school diploma (文凭) reported stress on 30 percent of the study days, people with a high school degree reported stress 38 percent of the time, and people with college degrees reported stress 44 percent of the time.

“Less advantaged people are less healthy on a daily basis and are more likely to have downward turns in their health.^” leading researcher, Dr. Joseph Grzywacz of Wake Forest University Baptist Medical Center, said in a prepared statement. “The downward turns in health were connected with daily stressors (紧张刺激物) , and the effect of daily stressors on their health is much more damaging for the less advantaged."

"If something happens every day, maybe it's not seen as a stressor.” Grzywacz says. “Maybe it is just life.”