It's almost Field Day! But Natalie's team isn't ready for the big race. Their muscles get tired easily. Ms. Starr teaches them about aerobic and anaerobic exercise. They learn some stretching exercises too. Now they're full of energy. Can they win the beach ball relay?

Gina Bellisario is the author of fiction and nonfiction books for young readers (and the grown-ups who read to them). She lives with her husband and their twin young readers in Park Ridge, Illinois.