We can define insurance as protection against a possible eventuality. In fantasy football, the most common form of insurance employed is the practice of "handcuffing" running backs. This investing strategy is the practice of acquiring the direct backup, or the handcuff in fantasy vernacular, to a starting running back.
Accuracy guru John Paulsen of 4for4.com efficiently details the intricacies of handcuffing tailbacks:
Handcuffing RBs is not an exact science. The importance of a handcuff depends on several factors, including the value of the starter in question, the durability of the starter, the talent (and price) of the handcuff, the overall clarity of the backfield situation and the roster size of your league.