Sentence:  After you have taken a breather , reverse the position of your <WSD>legs</WSD> so that the front thigh of the previous exercise is now to the rear , and the rear thigh now to the front , and perform the same movement in the same manner . 
Meaning of the word marked with <WSD> tags:  a human limb; commonly used to refer to a whole limb but technically only the part of the limb between the knee and ankle