2 . Not long after the first fitness magazine was published, a list probably followed soon after, ranking the best fitness equipment. This tradition has continued, with the implied message: use this and exercise will be yours.

And that's part of the problem, says Dr. Lieberman, a professor of Harvard University. There isn't one “best” anything to achieve fitness. Besides, people understand exercise is good for them. Knowledge about exercise still doesn't motivate.

Before you can answer why, it helps to look at history. Before the Industrial Revolution, people fetched water and walked up stairs because they had to. But then technology made life and work easier. Exercise has become something that people have to carve out time for. “It's a fundamental instinct to avoid physical activity when it's neither necessary nor rewarding,” he says.

It would seem like being healthy would qualify as necessary, but a doctor's prescription to exercise “can make it like taking cod liver oil,” Lieberman says. “Sometimes it works, but more often than not, it doesn't. And it's still coming across as an order, and “not having a heart attack in five years is not an immediate reward,” says Dr. Beth Frates, assistant professor at Harvard Medical School.

People might not want to exercise because it's never been enjoyable. Most of us probably have memories of gym class, not being picked for a team, or being in a fitness center that's filled with in-shape people. The majority don't feel excited. They feel that exercise isn't for them, but it can be. Coaching people in an empowering and motivating way can work much better than ordering someone to exercise. It starts with an expanded definition of what counts as exercise, and an injection of what's rarely used to describe exercise, but is certainly allowed: namely, fun.

4 . A lot of teenagers in middle school want to do more sports.     1    . But some students don't really know the benefits of doing sports. Here are some reasons for doing sports.

Watching TV and playing video games are becoming more and more popular among teenagers.     2    . But getting teenagers to take part in a sport gives them an opportunity to go out and socialize with others.     3    . What's more，they will learn how to work with others and get along with others harmoniously.

One of the biggest problems in our society today is obesity，and it's not just a problem with adults. More and more kids are becoming overweight.     4    .

Encouraging teenagers to do more sports also benefits parents. It is a great way for parents to show they love their kids.     5    . This is a great way for parents to spend time with their teenagers and talk to them.

Doing sports is a great way for teenagers to get out of the house，get moving，make friends and keep healthy. So why not join in and get into sports today？

8 . The use of technology reaches all areas of the school world, including the subject of Physical Education. But working at a distance and without going to the school may seem a little complicated. However, this selection of applications （apps）is ideal for bringing sports education out of school.

Munzee

A gaming app in which students participate through their smartphones. It consists of searching and catching 'munzee' throughout the city. The munzees are cards with a QR code（二维码）that the teacher will hide and that the students must find in order to obtain points and advance in the game. To play the game you only need a mobile device with GPS and Wi-Fi.

Activilandia

This app seeks to promote a balanced diet and the practice of physical exercise in children between 6 and 12 years of age. To this end, they have developed this virtual theme park to fight overweight. The game combines recreational and educational content to convey that with small changes in lifestyle great health benefits can be achieved.

FTT Radio

Motivation is part of the training: with a favorable mood, the performance of physical exercises becomes much more bearable and tiredness is less noticeable. Under this concept this app has been created, which contains a great amount of music with high energy to activate the body and the mind. In addition, it contains songs of all types to suit musical tastes.

Genius App Manager

It aims to encourage children to move around and to reduce the use of digital devices. It gives the possibility of having a parental control for adults to block some applications. It also offers functions such as setting time for homework, sleeping, eating or showering.

9 . Lloyd Black decided to join the Anytime Fitness gym in Semmes, Alabama last year after he found himself struggling to accomplish simple household tasks. The 91-year-old man hoped that joining a gym might help him build strength and reduce his aches and pains. Over the past year, Black has been faithfully coming to the gym three times a week. His overalls (工装裤) really catch plenty of attention. He says that he prefers to wear overalls during his workouts because they are comfortable, and he has “trouble keeping his trousers up” other-wise.

When Black first joined Anytime Fitness, gym manager Ashley Seaman said he could barely last 10 minutes on the treadmill (跑步机) without becoming winded. Now, however, the senior can effortlessly do power walking for thirty minutes before moving on to his workout routine. As a means of praising Black for his advance, Seaman recently named Black “Mem-ber of the Month”.

He also takes time to help other seniors new to the gym learn how to use the weightlifting machines. “He's just a friendly soul. He will go to the other elderly members and show them how to use the machines,” Seaman shared in a post on the gym's Facebook page. “Someone like him always encourages others to keep it up and include fitness in their life,” the post reads. “Seeing him work out three times a week in his overalls brightens our day!”

As a result of his work at the gym, Black finds it easier to mow (割) the seven acres of grass at his house and tool around in his woodworking shop. He experiences less daily dis-comfort and moves more easily. He always says, “Age is just a number and it doesn't mean you can't get into the gym.”

10 . The Biggest Stadiums in the World

People have been pouring into stadiums since the days of ancient Greece. In around 80 A.D., the Romans built the Colosseum, which remains the world’s best known stadium and continues to inform contemporary design. Rome’s Colosseum was 157 feet tall and had 80 entrances, seating 50,000 people. However, that was small fry compared with the city’s Circus Maximus, which accommodated around 250,000 people.

These days, safety regulations-not to mention the modern sports fan’s desire for a good view and comfortable seat — tend to keep stadium capacities (容量) slightly lower. Even soccer fans tend to have a seat each; gone are the days of thousands standing to watch the match.

For the biggest stadiums in the world, we have used data supplied by the World Atlas list so far, which ranks them by their stated permanent capacity, as well as updated information from official stadium websites.

All these stadiums are still functional, still open and still hosting the biggest events in world sport.

·Rungrado 1st of May Stadium, Pyongyang D.P.R. Korea. Capacity: 150,000. Opened: May 1,1989.

·Michigan Stadium, Ann Arbor, Michigan, U. S. Capacity: 107,601. Opened: October 1, 1927.

·Beaver Stadium, State College, Pennsylvania, U. S. Capacity: 106,572. Opened: September 17, 1960.

·Ohio Stadium, Columbus, Ohio, U. S. Capacity: 104,944. Opened: October 7,1922.

·Kyle Field, College Station, Texas, U. S. Capacity: 102,512. Opened: September 24, 1927.