The fourth-graders at Cape Horn-Skye Elementary in Washougal start their day with squats.The kids hold bright blue rubber stability balls over their heads and slowly squat toward the ground. They giggle during the first couple. By the fourth, though, they’re moaning about their sore legs.“Feel the burn,” teased Alice Yang, their teacher.Next, the abdominal crunches.With their bottoms on the ball and their feet on the ground, the kids lean back until their bodies are flat, count to three, then sit up. After a handful of crunches, the kids bounce on the balls for a few seconds to shake out the wiggles.Then it’s time to get to work.The kids roll their balls up to their desks, take a seat and get started on the day’s first lesson: identifying U.S. states from flashcards.About a month ago, the kids in Yang’s class swapped their hard metal chairs for squishy rubber stability balls. So far, the change is getting rave reviews.“It gives us more fluency and helps our brains,” said 10-year-old Alexis Perry. “It’s really cool having them.”Yang said she got the idea while researching ways to help restless students.This year, Yang said, she has many active kids who sometimes struggled to stay focused throughout the school day. They would get up to get a drink of water or sharpen their pencil or do anything, really, other than stay in their seat, she said.