Riverrunning (practitioners use one word) is the essential - and some would say most artful - form of kayaking. Whereas its derivative forms (described below under the headings of Creeking, Slalom, Playboating and Squirt boating) have evolved in response to the challenges posed by riverrunning, such as pushing the levels of difficulty and/or competing, riverrunning, of its own right, is more about combining one's paddling abilities and navigational skills with the movements and environments of rivers themselves. Important to a riverrunner is the experience and expression of the river in its continuity rather than, say, a penchant for its punctuated "vertical" features (e.g. standing waves, play-holes and waterfalls). As for kayak design, a "pure" riverrunning boat can be said to have "driving ability" - a blend of qualities that enables the paddler to make the most of the differential forces in the river's currents. For example, instead of spinning or pivoting the boat to change its direction, a riverrunner will drive the boat in such a way as to make use of the river's surface features (e.g. waves, holes and eddylines) thus conserving the boat's speed and momentum (this is in particular contrast to slalom racing, where, in the attempt to negotiate certain kinds of slalom gates, the boater will pivot the boat to change its direction, and by so doing, diminish the boat's speed and momentum.) A principal design characteristic of riverrunning kayaks (as well as for their closest cousin the slalom boat) is their comparatively longer length and narrower breadth (generally minimum 285 cm in length and maximum 63 cm in breadth). The longer length at the waterline not only helps to carry speed but the longer arcs thus created between stem and stern allow the boater to more efficiently and gracefully carve into, through and out of eddies and other currents.
Creeking is perhaps best thought of as a subcategory of river running, involving very technical and difficult rapids, typically in the Grade/Class IV to VI range. While people will differ on the definition, creeking generally involves higher gradient (approaching or in excess of 100 ft per mi (19 m per km)), and is likely to include running ledges, slides, and waterfalls on relatively small and tight rivers, though some will allow for very large and big volume rivers in their definition. Kayaks used for creeking usually have higher volume (more gallons or litres of displacement) and more rounded bow and stern, as these features provide an extra margin of safety against the likelihood of pinning (getting a kayak wedged in such a way that it cannot be removed without a mechanical advantage system, such as between rocks and/or underwater), and will resurface more quickly and controllably when coming off larger drops. Creek boats usually have increased "rocker," or rise, fore and aft of the cockpit for manoeuvrability. Extreme racing is a competitive form of this aspect of whitewater kayaking, in which kayakers race down steep sections and/or generally dangerous sections of whitewater.
Slalom is a technical competitive form of kayaking, and one of the whitewater events to appear in the Olympic Games. Racers attempt to make their way from the top to the bottom of a designated section of river as fast as possible, while correctly negotiating gates (a series of double-poles suspended vertically over the river). There are usually 18-25 gates in a race which must be navigated in sequential order. Green gates must be negotiated in a downstream direction, red gates in an upstream direction. The events are typically conducted on Grade/Class II to Grade/Class IV water, but the placement of the gates, and precision necessary to paddle them fast and "clean" (without touching a pole and adding 2 seconds to the total time), makes the moves much harder than the water's difficulty suggests. Pro level slalom competitions have specific length (350 cm (140 in) for kayaks - new rules), width, and weight requirements for the boats, which will be made out of kevlar/fibreglass/carbon fiber composites to be lightweight and have faster hull speed. Plastic whitewater kayaks can be used in citizen-level races.
Playboating, also known as Freestyle or Rodeo, is a more gymnastic and artistic kind of kayaking. While the other varieties of kayaking generally involve going from Point A to Point B, playboaters often stay in one spot in the river (usually in a hole, pourover or on a wave) where they work with and against the dynamic forces of the river to perform a variety of manoeuvres. These can include surfing, spinning, and various vertical moves (cartwheels, loops, blunts, pistol and donkey flips, and many others), spinning the boat on all possible axes of rotation. More recently, aerial moves have become accessible, where paddlers perform tricks having gained air from using the speed and bounce of the wave. Kayaks used for playboating generally have relatively low volume in the bow and stern, allowing the paddler to submerge the ends of the kayak with relative ease. Competitions for playboating or freestyle are sometimes called whitewater rodeo in the US, but more frequently just referred to as freestyle events in UK and Europe.
Squirt boating incorporates the use of low-volume boats to perform special moves in whitewater features. Squirt boating predates, and was critical to the foundation of, playboating. Squirt boats are often fairly long and flat, with low volume throughout the design. Because squirt boats are custom built to the paddlers weight, inseam, and personal preference, they are constructed with composite materials instead of plastic. Many squirt moves are intended to submerge all or part of the craft and paddler, such as the "mystery move," in which both the boat and the paddler submerge completely into the river's flow for several seconds and up to half a minute.