ABOARD NORWEGIAN BREAKAWAY (AP) — I’d been at sea on Norwegian Cruise Line’s new ship, Norwegian Breakaway, for more than 14 hours but I didn’t feel the ship moving until I tried to do a dance move with the Rockettes.Yes, the Rockettes, of Radio City Christmas Spectacular fame, those lithe and lovely young women known for a perfectly synchronized kick line. The Rockettes are the godmothers for the ship, and a dozen of them performed their famous moves at the ship’s christening last week in New York.Several of them then accompanied the ship on an inaugural cruise to nowhere, out to sea and back in two days, and they hosted a fitness class for passengers designed by their athletic trainer, Elaine Winslow, herself a former Rockette.A confession: I’ve only seen the Rockettes at Radio City Music Hall once, in second grade, and the last time I took an exercise class was before I was of legal drinking age. Could there be a better candidate to participate in a Rockettes fitness class than me, an out-of-shape 50-something who can’t even call herself a fan?All I can say is, I went in a cynic and came out an admirer. The Rockettes are not only perfect, and beautiful, but they are kind, gracious and fun, so much so that despite my two left feet and inability to follow their moves with any accuracy or grace, I had a total blast and would do the class again in a minute.Winslow divided the class of mostly middle-aged women — none of whom looked like gonzo Jane Fonda types to me — into two groups: regular and moderate. I hightailed it over to the moderate side and tried to follow along as we learned the exercises one by one, then did them in sequence to music. My group stayed in place while the other group moved across the floor.While I don’t work out, I’m not a total couch potato. I can walk a few miles at a brisk pace with no trouble. So I didn’t find the exercises — mostly gentle stretches and bends — impossible, but I couldn’t do them as fast or as well as my classmates. I certainly couldn’t do them as well as the dancers, who stood among us demonstrating and inquiring periodically with a dazzling smile if we were all feeling OK.Winslow led the class at the front of the room, noting among other things that the secret to all those kicks is in the hip muscles, which must be warmed up and strengthened to do the hundreds of kicks a day required when the Christmas show is in season.Future cruisers should know that the classes will not be offered on every sailing, but only when the Rockettes are on the ship. Two Rockettes are sailing on each of Norwegian Breakaway’s first six trips, and then on the first cruise of each month thereafter, and they will host the classes when they’re onboard.And no, we did not attempt the famous eye-high kick — where the dancers move their legs so high and so fast that their feet are practically at eye-level. But we were taught a related move I could not master: Balancing back on the left heel, with toes in the air, we were told to kick the right foot up — not high, but enough so that every time I tried it, I nearly fell down.Not only was this impossible for me, but I suddenly noticed that in addition to my lack of coordination, the floor seemed to be moving beneath my feet. Oh right, I suddenly realized, I’m on a cruise ship, on the ocean. And I’m trying to do a dance move with the Rockettes. No wonder I was feeling dizzy!No harm done though. I walked out after an hour with a grin on my face and a notch in my belt: I survived a fitness class with the Rockettes, and I had fun doing it.