2 . Teenagers' fitness is now a major concern, to which physical exercise is very important. It reduces stress and improves fitness. Exercise makes your body strong, and helps you to keep the right body weight. Sports scientist Dr. Helen Lopez offers the following advice to teenagers: "First, you need to find out your present level of fitness.Then you can design a programme that will help you become healthier."

Dr. Lopez suggests that there are three levels of fitness that need a change of lifestyle. "Overweight" means that the person gets very little exercise and often has a serious weight problem."Inactive" means that the person does not join in many physical activities, but is not seriously overweight. "Active" refers to people who take part in sports and other physical activities, but are not at a high fitness level.

According to Dr. Lopez, overweight teenagers should keep active to keep healthy. "Ride a bike, play volleyball or basketball for a while, and go for a twenty- minute walk each day. All these will help to burn calories." Inactive teenagers should do similar activities, but add some bending and stretching exercises, such as push-ups and sit-ups, starting with twenty each day. "Inactive people can take a little more exercise than overweight people because their bodies are stronger," said Dr. Lopez. The same principle applies to active teenagers.

Dr. Lopez suggests one hour a week or more on running and other forms of intensive exercise (强化训练), together with fifteen minutes a day spent on stretching and bending activities. "These are really important in order to prevent injuries," Dr. Lopez said. Some weight-training and other body-strengthening exercises could also be planned in the programme in order to increase the person's strength.

4 . Group exercise is one of the most effective ways to improve physical fitness and maintain a healthy lifestyle. Group exercise is challenging, yet fun and empowering! Of course everyone knows that exercise is good for the body. However, studies have shown that when exercise is performed in groups, it’s not only great for improving physical health but for psychological health. It’s an opportunity to be social, release endorphins(内啡肽), and improve your strength. Additionally, group exercise creates a community feel and the shared common goal motivates participants to work hard. The instrumental support of taking on a fitness journey with others proves more effective than going to the gym alone.

Another beneficial aspect of group exercise is the informational support participants receive from the instructor. Many people fear the gym because they feel lost and don’t want to embarrass themselves. If you feel you can relate, then group training is an even better option for you. It’s a great opportunity to learn more about fitness through the clear instruction and supervision of a fitness instructor. If you’re tired of wandering around the gym wasting time and becoming bored, you can attend a cheerful group fitness class that’ll keep your workout on track. Don’t let fitness frighten you!

If you’re serious about wanting to live a healthy lifestyle, it’s extremely important to surround yourself with people who’ll provide you with the proper emotional support. I wouldn’t scold anyone for deciding to party on weekends and in turn I wouldn’t expect anyone to give offence to me for focusing on my health. Surround yourself with people who uplift, encourage and understand you! Make fitness even more fun by trying something new or any group fitness class, with a friend. Plan to go for a jog together. Then try a fun healthy restaurant or fresh juice bar! Fitness can be both fun and social!

Surrounding yourself with people who’ll provide you with respect and support can be very beneficial while working towards reaching health and fitness goals. First, decide to do it for yourself and work towards staying positive. Then make sure the people you surround yourself with are supportive. Don’t let negativity ruin your motivation.

6 . I come from a family that loves sports. My father coaches Little League baseball. My mother swims nearly every weekend. My brother is on his high-school basketball team, and I am the best hitter on my middle-school volleyball team. All of us have benefited(受益）from sports. One of the most common ways for kids to take part in sports is to join a team. Joining a sports team should be a school requirement.

Playing sports is good for both the body and mind. Everyone knows that exercise helps people stay fit. For example, swimming helps your heart work better and it also helps build muscle strength(肌肉力量）. In addition, school athletes(运动员） often have a healthy diet. I eat a lot of fruit and vegetables and avoid fatty foods because I must stay in great condition.

Being on a team allows students to enjoy a healthier social life. They often make more friends and can be some of the most popular kids in school. Since joining the basketball team, my brother has made friends with a lot of his tea mates and has showed more interest in spending time with them.

Kids who take part in school teams sometimes earn college scholarships(奖学金）. My brother's friend, Justin, played football in high school. His family did not have money to send him to college. However, a college invited him to play on its team. The college is paying for him to go to school. Joining a team turned out to be one of the best decisions he had ever made. Now he studies at a great college and plays on its football team Not every school athlete gets a college scholarship, but joining a school team-makes it possible.

Although some people may not like the idea of forcing students to join a school team, its many benefits such as keeping kids heal thy, new friendships, and possible scholarships cannot be denied(否认）.

7 . Is running a marathon (马拉松) under two hours possible? Will a human ever be able to run that fast? Now, the world record for the 42.195km (26.219 miles) distance is held by the Kenyan runner Eliud Kipchoge. His time of 2:01:39 hours was achieved at the Berlin Marathon of 2018.

But studies published in the past have come to the conclusion that running a marathon under 2 hours can be done. They even see a time of around 1:57 as the fastest a human can ever run. However, we may have to wait longer for this to happen.

To achieve an under two-hour marathon, an athlete would have to have the perfect body size and weight, the right running plans and of course, the right nutrition (营养). Today’s perfect runners come from Kenya and Ethiopia, countries that have dominated (占优势) long distance races for years. East African athletes have long legs and lungs that can take in lots of oxygen (氧). Training at high altitudes (海拔) gives them a strong heart. Ideal weather conditions with cool temperatures and no wind will also be needed to attempt such a mark. An extremely fast marathon would only be possible on flat city courses, like Berlin or London.

Since the beginning of the modern Olympic Games in 1896, athletes have tried to run long distance races as fast as possible. In 1900, the marathon world record was at around 3 hours. In the following 30 years, men were able to reach a mark of 2:30. But in the last 15 years, the world record has improved by only 3 minutes.

On the other side, some experts think that such fast performances will only be possible with the help of some medicine.

8 . There's more evidence that what's good for your heart is good for your head. A new study shows that people who run, swim or do other moderate intensity （中等强度）exercise have brains that look, on average, 10 years younger than the brains of couch potatoes.

“Our study showed that for older people, getting moderate intensity exercise may be protective, helping them keep their brains work better," said Dr. Clinton Wright of the University of Miami, who led the study. But it's not necessarily easy. Walking, golf, bowling and yoga don't count, and people need to start before they begin showing memory loss, Wright' s team reported in the journal Neurology.

The study of nearly 900 people who exercise regularly showed that 90 percent fell into the low-intensity group. These people are part of a larger group taking part in a bigger study called Northern Manhattan Study. They were asked how long and how often they exercised during the past two weeks. Five years later, they were tested for memory and thinking skills and got a brain MRI. Seven years after that, they took the memory and thinking tests again. The 10 percent who said they took part in moderate intensity exercise scored better on the tests. These included running, climbing, swimming, riding bicycles and so on.

“We found that those with moderate intensity activity had higher scores and slower decline than inactive people when comparing the results," the study team wrote.

Many studies have shown that exercise may not prevent Alzheimer's disease but may delay it. The findings fit in with a study that found two years of exercising, eating healthier food and brain training can promote people's memory function.

9 . Until quarantine (隔离期) ends, we are left picturing what sport we might do: working out at the gym, playing on a competitive sports team, swimming, biking, or rock climbing. However, we don’t often think of martial arts as possible activities; instead, we rule it out because we think it’s dangerous, uncommon, and even, impossible. Martial arts aren’t considered a sport, right?

Well, here’s some good news: you’re wrong! Martial arts aren’t much more common than people think, and you can start learning at any age. Practicing martial arts is a great way to keep in shape, both physically and mentally. They’re much less boring and much less arduous sport than they’re usually described as in movies, so do not worry that they need a lot of effort.

Martial arts generally require you to focus on the position and movement of every one of your legs and arms, sometimes even your breathing too. Think about it: when you leave the gym, your mental state has improved and you are much calmer. This is because you’ve only paid attention to one activity. It is a great way to clear your head. And practicing it can help you learn to stay more focused, which is the greatest advantage of martial arts training.

Martial arts also improve your coordination (协调性), and greatly improve your posture (姿势). I have personally seen students go from slouching (没精打采) to walking tall with their shoulders back in just a couple of months.

There are many styles and countless kinds of martial arts. Whichever one you like better, know that all of them are good choices.