An archery bow includes a cam assembly rotatably supported at a pivot axis on a limb of the bow. The cam assembly includes a primary string feed-out which operates to feed out a length of a bowstring as the bow is drawn. The cam assembly includes a control system associated with a secondary string feed-out. The control system is operative, during the time the bow is being drawn and the primary string is being fed out, to control the effective length of a secondary portion of the string such that during an initial portion of the draw of the bow, the effective length of that secondary portion decreases and so that during a subsequent portion of the draw, the effective length increases. The controller thereby operates to modify the force draw profile of the bow so as to increase the amount of energy stored therein during the initial portion of the draw.