Fast action rods have a stiffer tip section that bends mainly in the upper third or quarter of the rod. This provides greater sensitivity and allows for quick hook sets, making them suitable for techniques that require precision and responsiveness, such as jigging or worm fishing. Moderate action rods have a more gradual bend throughout the rod's length, offering a more forgiving and flexible feel. They excel in techniques that require better lure control, such as crankbait fishing.