premise: She had a little tape recorder , and turned it on to play the same music as before . Though I was still dizzy , I began to dance again , only slightly more aware of how goofy I looked because I could see my shadow dancing with me on the sand . The song went on and on , and I started getting tired . I said , " It 's like the Red Shoes , is n't it ? " What 's a possible reason the writer started getting tired ?
hypothesis: Because dancing is a physical activity .