Muscle fibers

Muscle fibers are like tiny, stretchy ropes inside our muscles that help us move our bodies. Think of a rubber band that you can stretch and pull. Each muscle in your body has lots of these tiny fibers that work together to make you move.

There are two different types of muscle fibers: slow-twitch and fast-twitch. Slow-twitch fibers are great for things like running long distances, while fast-twitch fibers are useful for sprinting or lifting heavy weights.

When you exercise or use your muscles, these tiny fibers get bigger and stronger. It's like building a bridge or a tower out of blocks - the more blocks you stack together, the stronger and taller your tower becomes.

Overall, muscle fibers are super important for helping us move and stay active, and they come in different types to help us with different kinds of activities.