Sentence:  `` We could put up cribs on the second floor sleeping porch and turn the front bedroom into a playroom where it 's nice and sunny , but of course it would entail quite a bit of <WSD>running</WSD> up and down stairs and Chris said you were to be careful about that '' . 
Meaning of the word marked with <WSD> tags:  move fast by using one's feet, with one foot off the ground at any given time