Once upon a time, in a cozy little town, there was a boy named Timmy who loved to play and jump around. One sunny morning, he woke up feeling funny in his legs and arms; they were very, very sore.

Timmy tried to leap out of bed as he always did, but this time he wobbled and let out a 'Yikes!' His muscles felt like they had been turned into wiggly noodles while he was sleeping.

The night before, Timmy had been on a grand adventure at the playground, climbing like a monkey and running faster than a speeding rocket. 'That must be it!' he exclaimed. 'I have super muscles now!'

Timmy's mom heard the ruckus and came to check on him. She explained that what Timmy was feeling was something called muscle soreness, and it happened when they played a lot!

'Your muscles are growing stronger,' she said, giving him a gentle hug. 'But since they're not used to so much superhero work, they need a bit of rest.'

Timmy spent the day reading his favorite comics and telling his teddy bears about his mighty muscles. He imagined himself as a superhero, saving the day and lifting really heavy things with ease.

The next morning, Timmy felt much better. His muscles weren't ouchy anymore. He jumped out of bed, ready for new adventures, knowing that his muscles were just a little bit mightier than before.