Sentence:  On the kick-off, Cochran ran the ball back to the thirty-eight-yard line. It took only seventeen plays, most of them off tackle plunges, before Houlahan slid over the line on a <WSD>crossback</WSD> for the touchdown. 
Meaning of the word marked with <WSD> tags:  A play in which the player with the ball crosses to one side of the field and then doubles back to the other.