In fishing rods, the action is an index that describes the amount of flexion of the shaft subjected to an effort and indirectly, the speed with which the shaft will return to its natural position. It is predominantly influenced by two aspects; the type of material used and the construction choice. In fact, we know that carbon is more rigid than glass fiber and that constructive choices such as the distribution of the material fibers, the length or section of the elements that make up the stem, the number of elements or the type of rings (bridge rings single or double), etc .. can greatly modify the action of the rod.

The action is sometimes described by the terms SLOW, MEDIUM, FAST and EXTRA FAST and possible combinations, while other times (especially in carp fishing or tuna rods) it is indicated in pounds (lb) and is called Test Curve (TC). A SLOW action rod is a very soft rod whose blank flexes a lot and will take longer to return to its normal position. If we were to express the SLOW action in LBS it would correspond to a low poundage to indicate that with little pressure the shaft begins to flex. Be careful not to confuse the action of the rod with casting power or optimal casting weight. The two do not always have a direct relationship.

The action of the rod therefore tells us how much and how the barrel of the rod flexes when subjected to an effort such as casting or fighting with the fish.