Kids need to exercise for health just like adults do. But just 50 percent of boys and less than 34 percent of girls ages 12 to 15 are adequately fit, according to the Center of Diseases Control and Prevention.
I’m mother of 14-year-old twins who love exercise and sports. In fact, my son got 3rd place in the Karate World Championships and my daughter is a very good tennis player. But was this easy? Yes and no. My husband and I like to practice different sports and disciplines; we do karate, lift weights together and run. So my advice is to set a good example. When my kids turned 4, I introduced them to different sports so that they could follow the one that they like the most. We firmly believe that young people involved in sports are more confident and develop discipline. Also some research suggests that can help your kids to fight off diseases.
When teens start going out to party, sports and exercise routines can be the key to balance their lifestyle. Teens involved in sports are more disciplined and develop healthier habits, and sometimes prefer to get to sleep early and eat healthy rather than going out to party. Practicing exercise also helps to release tension and stress, increase energy and prevent obesity. 
Here are some easy ways to get your kids to love exercise.
1. Parents are role models, so be active and set a good example. Practice sports and show your kids the benefits. Let them know the importance of exercise for your health and life.
2. Be a family team. Practice sports that can be enjoyed by the entire family, and be partners! Play soccer, play tennis, do push-ups, run, play with a ball, walk in a park … be creative and motivate them to have a fit lifestyle. Also create goals and awards! This healthy competitive motivation will help get them interested.
3. Use physical activity in daily life. Bike or walk to and from school, try the stairs instead of the elevator, walk to the grocery store, walk the dog, etc.
4. Go to a sports match. The enthusiasm is a good way to show your kids that sports can be fun! Go see a professional soccer game, basketball game, baseball game, tennis tournament, etc. Try to identify a sport that connects with your kids.
5. Play games. Invite their friends and dance, run, play hide and seek. You don’t need a lot of equipment to get your kids moving and make it fun.
6. Make it a habit. Schedule workouts, select sport activity classes, or have them join a league or after-school activity.
7. Find sports that can be fun for them. Swimming, skating, rope jumping, hiking, climbing, gym, riding horses, Wii— there are many fit exercise options. Keep trying different things until they find something they like.
8. Kids love it when their parents play or exercise with them! It’s also a good way to spend quality time together: talk, play and sweat!
9. Don’t push them, but find a sport that they are comfortable and happy with. Don’t decide for them!
10. Talk with your pediatrician. Ask your pediatrician about what type of exercise is recommended, and have him or her explain to your child the importance of being active.
References
*The Center for Disease Control and Prevention.
http://www.webmd.com/parenting/features/kid-fitness-when-your-child-wont-exercise
