What makes muscles grow? - Jeffrey Siegel?

Muscles grow when they work hard and get proper rest, just like a toy that gets stronger after playing and sleeping.

Imagine your muscles are like little superheroes who fight battles every day, when you run, jump, or lift things. Each time they fight, they get tiny injuries called microtears. These aren’t bad, in fact, they’re part of how muscles grow!

After the battle (or workout), your muscles need to rest so they can heal and become bigger and stronger. It’s like when you fall off your bike, you get a little scrape, then you rest and it gets better. Your muscles do something similar: they repair the microtears, and in the process, they grow.

Think of it as building a treehouse. Every time you add a new part (like a ladder or a roof), it makes your treehouse bigger, just like how muscles get bigger when they work hard and rest well.