Sentence:  Mr. Claude is a <WSD>specialist</WSD> in torso development and he has long favored the now famous Weider Push-Pull Super-Set technique in which one exercise of the Super-Set is a pressing or `` pushing '' movement which accents one sector of a muscle group in a specific way , followed by a `` pulling '' exercise which works the opposing sector of the same muscle group . 
Meaning of the word marked with <WSD> tags:  an expert who is devoted to one occupation or branch of learning