The expression is understood as " not to assign " , " do not accept a defeat ( before someone ) ". It comes from a competition of strength and endurance known as tug of war, where the contenders feel front supporting two separate rights elbows on a table and taking their hands trying to take with force the opponent to his left forearm. Who resists is which never ceases to twist his arm, and wins who manages to twist the arm of the other.
