Flip Flops, Are They Shoes?

This picture is provided by the Biomechanics Laboratory of the Shanghai Institute of physical culture. The 4. left feet are separated from the ground, and the resultant force is stable before the center of gravity.

3. left or right leg alternately, the force exerted on the left leg is greater than the right leg.

2. around the legs, close to the center and prepare for moving forward.

1. the left leg is in front and the full direction is in front of the center of gravity, supporting the body.

Sunday morning news reporter Dai Zhendong

"Flip flops", also known as "toe slippers", are becoming more and more popular among young people over the years.

Especially in midsummer, looking around, you will find that many people wear this "bikini" with excellent permeability.

The English character called "Flip-Flops" reads like a "tap kick" rhythm.

But some recent rumors have made the rash of the flip flops become tense.

ABC news and other media recently released a news about "flip flops", which reported that Wendy Weimar, a professor of biomechanics at Auburn University, conducted a series of experiments on "flip flops". Experiments showed that the "flip flops" really do not save people's worries. Because of the design flaws in the sky, wearing flip flops will change walking gait and induce foot diseases.

In the TV coverage of the American media, many beautiful models were also invited to demonstrate.

There are also some reprints in the domestic media and the Internet. Many people also ask questions. They usually wear flip flops to and from work. How come there is no discomfort?

Is the flip flops really scary?

In order to understand the specific process and results of the experiment.

The reporter interviewed Professor Wendy Weimar and the project leader, Justin Sawyer, who did a flip flop experiment by e-mail.

"We don't have enough evidence yet."

Justin Sawyer is a graduate student of Wendy Weimar, who is responsible for the flip flops experiment.

Like all fashionable young people, Sawyer always wears flip flops in summer.

Sawyer studied the field of human walking and footwear.

Once, when he consulted with his tutor in Weimar and looked at his slippers, he suddenly remembered that many students complained to him that they felt uncomfortable after their summer holidays, and that the athletes in schools also had such reactions.

In 2006, AmericanCollegeofFoot and ankle surgeon sargson found that after the summer, more and more people were suffering from foot pain in the teen age group. They suspect that this trend is related to fashionable trendy slippers.

Sawyer thought it would be better to do an experiment to see if the flip flops were the main culprit.

Sawyer recruited 39 volunteers from his classmates, who were divided into two different groups. One group wore sneakers, one group wore slippers. Two groups wore one day each day, second days later, they were tested in the laboratory.

In order to make the data as objective as possible, the flip flops provided in the experiments come from different businesses, ranging from 5 US dollars to 50 dollars.

The process of testing is simple. The five toes, ankles, knees and hip joints of the experimenter are equipped with sensors. They walk through a platform, and multiple cameras will take pictures of their walking.

The platform that people walk can record the strength that the foot and platform surface touch for a moment.

At the same time, the movements of the experimenters when walking, and any subtle movements of their hips, legs, ankles, feet and toes are recorded by the video system.

Taking the experimental summary provided by Sawyer to reporters, assistant professor of biomechanics at Shanghai Institute of Physical Education, Professor Zhang Shengnian helped reporters interpret the contents of the experiment.

Zhang Shengnian told reporters that from the data provided by the experimental summary, the experiment only tested the vertical strength of their walking, and the data only showed that the strength of the two groups of people walking was different.

In fact, each person walking gait is not the same, it is difficult to explain the problem through this data.

So why did the media talk about this experiment?

Sawyer said wrongfully, "our research actually does not mean that the foot affects our health. The purpose of our experiment is to compare the walking steps of people wearing flip flops and walking steps with sneakers.

Our aim is to see if people walk in flip flops. "

The report of the media combines some hearsay and surgeon's explanation, which makes the result of Sawyer's experiment changed beyond recognition.

Sawyer said, "we don't want people to stop wearing flip flops. We are not saying that flip flops are bad for people. Through research, we just show that when comparing kinematic and dynamic variables, people wear flip flops when walking."

But Sawyer also believes that running shoes are designed for running. Hiking boots are designed for hiking. Flip flops are designed for easy walking in beaches or swimming pools, rather than for all-weather walking.

Sawyer told reporters that he was preparing to continue his research on flip flops.

He said he hoped that the study would be more scientific and clear about the question of "flip flops".

Analysis of Surgeons

Locke Postino, a foot surgeon of the New York Special Surgery Hospital (HospitalforSpecialSurgery, world famous surgical hospital), once told the media about his views on the problem of "rash pull". This time, he also introduced his views to the Sunday Morning Post reporter.

Bo Steno told reporters that the effective support of the arch is the biggest problem of the flip flops. The arch is supported by interacted muscles, such as tendons and ligaments.

When we walk, the arch is equivalent to the shock absorber. Sports shoes or other shoes can provide enough support to reduce the pressure on our feet and ligaments, and help our feet work more efficiently.

When there is no support for the arch of the foot, when walking on the ground, most of the feet will have the tendency of turning inward. (internal arch and internal eight are two different gestures). When we walk inside, the arch can not play the role of shock absorbers, thus causing abnormal pressure to other parts of the foot, such as the ankle, which will eventually cause chronic and serious injuries, such as tendinitis.

In addition, Bo Steno warned people that wearing slippers on slippers must be especially careful when walking on uneven roads. Foot slippers can twist the feet in any direction, which may lead to ligament damage or fracture.

Also, for example, people with diabetes or some circulatory problems have to be especially careful when wearing flip flops, because they lack skin protection and are vulnerable to skin damage.

Bo Steno said that more and more people complained about their knee pain, hip pain and back pain, which made people realize that these problems may be related to long wearing flip flops.

However, Perino did not give any real clinical cases to show that all this must be relevant.

Cao Cong, an Department of orthopedics doctor at Yan Chai Hospital, also believes that flip flops may be pathogenic.

However, he differs from perdino's argument.

He thinks that Bo's problem is ignored. Many brands of "flip flops" on the market have enough support for the arch, and we can see that the part of the slippers that bulge up is designed to fit the arch of the foot.

Cao Cong said, the normal shoes, when the force is the first and fifth phalanges, the heel to the ground, the three points to form a face, the force is very uniform, the toes are resting state.

The flat foot is the exception, because the uneven distribution of the three points of the flat foot leads to improper force.

The mechanical structure of the flip flops is similar to the lever principle. The first and second webbed parts of the toes are in the direction of control. The intersection point of "human" is actually a fulcrum, with five toes down enough, and the heels can be tightly attached to the upper.

The problem is on the frenulum.

In general, sandals have a frenulum, and the ankles are secured to the ankles without fear of shedding of heels and vamp.

If you do enough toes, if you do enough, it will easily cause plantar fasciitis (the pain starts from the front part of your heel and spreads to five toes, triangular areas).

Because all joints of the foot are related to each other, for example, the heel should be close to the upper surface, the Achilles tendon must be contracted, the toe will be pressed down, and the ankle joint will be pressed downward.

Bo Steno said, "causing pain in the heel, knee joint, hip joint, or even back." this is due to plantar fasciitis and Achilles tendinitis. The soft tissues of the calf, knee, hip and back are not normally stressed, resulting in a chain reaction of muscle strain.

But Cao Cong also said that surgeons could rationally analyze the complex causes of the disease, but he could not give any practical clinical cases to illustrate the problem.

Cao Cong said that before we could use data or evidence to speak, everything was still doubted and speculated.