Sentence:  It is made up of tumbling , which might be said to start with a somersault , run through such stunts as headstands , handstands , <WSD>cartwheels</WSD> , backbends , and culminate in nearly impossible combinations of aerial flips and twists and apparatus work . 
Meaning of the word marked with <WSD> tags:  acrobatic revolutions with the body turned sideways and the arms and legs outstretched like the spokes of a wheel