Experts checked over 417,000 kids in 20 countries. They found kids have less muscle strength and flexibility than 40 years ago. Many kids also have more body fat now. Experts did this big study.

Doctors say playing and exercise keep hearts and bodies healthy. Over 75% of European teens do not move enough daily. Experts say schools and cities must help kids exercise daily. It helps them stay healthy. Exercise is very important.

Some hard words are: health, muscle strength, and flexibility. These words are about how strong and fit you are.

You can watch the original video in Level 3.