Toddlerobics

Talk about putting readers through their paces-a brisk rhyming text urges kids out of their armchairs and onto the floor for a swift, nifty workout: ""Lift that rattle in the air-shake it, shake it, everywhere!"" Showing eight toddlers as they clap and stamp and stretch and twirl, Newcome's (Rosie Goes Exploring) tidy watercolor and crayon compositions stress the children's fun and their friendship. Endpapers introduce each member of this ethnically diverse class by name, from Alphonse to Vikram, thereby personalizing the reader's various vicarious gym partners. With activities like ""wriggle your toes, crawl like a cat, now lie down and stretch out flat,"" kids will happily join in. Ages 2-4. (Apr.)