... Toronto London Auckland Sydney Mexico City New Delhi Hong Kong Buenos Aires What your muscles do? Muscles help your body move Fun Fact Hundreds of muscles help you take one step Muscles pull ... them a lot Muscles help you swim Muscles help you run Fun Fact Your heart and breathing muscles never get tired Muscles make your heart beat Muscles help you breathe Muscles let you smile ... to smile Muscles let you frown Fact Your stomach muscles work without you thinking about them Muscles help you swallow stomach Muscles push food through your body Fun Fact Bigger muscles can...