a book or walking down the stairs. But what about using them for harder stuff, like taking long bike rides or climbing a tree? That's where exercise comes in: it makes your muscles get stronger and sometimes larger. As your muscles get stronger, you can do more active things for longer periods of time and strong muscles also help protect you from injuries when you exercise, because they give better support to your joints (where your bones meet). (Schmitt p. 179)
             Exercise makes you flexible. Can you touch your toes easily without yelling "ouch"? Most kids are pretty flexible, which means that they can bend and stretch their bodies without too much trouble. But as people get older they tend to get less flexible, so that's why it's important to exercise when you're a kid - so you can stay flexible. Plus, when you're flexible, you can be more active without having to worry about getting sprains and strained muscles. Luckily, it's easy to find things to do for good flexibility. Tumbling and gymnastics are great ways to become more flexible as are yoga and dancing, especially ballet. And for fans of karate, tae kwon do, and other martial arts, you're in luck: these sports are great for flexibility - you'll be feeling fine and having fun! (Schmitt p. 627)
             Exercise makes you feel good. Exercising is a most excellent way to feel happy, whether you're exercising on your own or with a group. If you've had a tough day at school, a fight with your friend, or just feel kind of blue, exercising can help you feel better. That's because when you exercise, your body can release endorphins, chemicals that create a happy feeling in your brain. Plus, when you're breathing deeply during exercise and bringing more air into your lungs, your brain appreciates the extra oxygen. And when you're active and running around, sometimes it's hard to think about just what was bothering you. Exercise can make you feel better about yourself, too. W...