Sentence:  Tim felt himself lowered a few inches, his feet finding the ground again, and, as Debuffier's hand reared back to deliver a paralyzing blow to the head, Tim rotated in, Green Beret style, a <WSD>downstriking</WSD> punch to the groin, quick and hard like a bear river-plunging for fish. 
Meaning of the word marked with <WSD> tags:  To strike from above.