Carrie came running into the house screaming at the top of her lungs, and collapsed at Laura's still moving feet. "What's the matter baby? What happened," Laura asked as she stooped down to look at the minor scrape on Carrie's knee. "Matty pushed me down on the swing," she said through stained lips. "He pushed me real hard." Carries put her head down in Laura's lap there in the kitchen floor. She swooped Carrie up with a little extra spin just for fun. "Let's go put a cool band aid on it, and you can go show him that all he did was get you a sticker," Laura said to her trying to cheer her up. Carries snuggled tighter to her mom as Laura flipped the bathroom light on. In the medicine cabinet, she always kept Hello Kitty and Power Ranger band aids, just in case of this happening. After cleaning the cut with antiseptic, and kissing her now happy little girl, Laura had put a hot pink band aid with Hello Kitty smiling brightly from Carrie's knee. It wasn't two minutes later that she was right out the door to show the boys how tough she was. 
Question: How did they get injured?
They were pushed down.