What causes muscle weakness?

Muscle weakness happens when your muscles can't work as hard or as long as they usually do.

Imagine your muscles are like little engines inside your body. When you run, jump, or even sit up, these engines need fuel to keep going. If they don’t get enough fuel, they slow down, and that’s when you feel weak.

Sometimes, your muscles can't take in the fuel they need. It's like trying to fill up a toy car with gas but having a tiny straw, it just takes too long. This can happen if your body has trouble moving food into your muscles.

Other times, the engines themselves get tired, just like you after playing all day. That’s why when you’re sick or not sleeping enough, your muscles feel weaker. They need rest to recharge.

So muscle weakness is like a sleepy engine, it can't do its job as well until it gets more fuel or some time to rest.