In the old days (about ten years ago), we really did not know much about snowboard technique. Our understanding of technique came from knowledge that was borrowed from other sports, namely skiing. This did not seem to matter for many top riders, they just rode. They rode with each other, and pushed each other to new limits. Equipment was changing each season and technique was changing with it.
As a technician trying to understand what was going on, this was very difficult because the best riders did not always understand what they were doing. They just did it. The way they described what they felt did not always jive with what we saw on video. The models we used for understanding ski technique did not always work when analyzing snowboard technique. Technicians were creating new theories almost everyday to explain technique.
Maybe the most significant of these theories was that of pressuring an edge, or controlling pressure along an edge. This idea not only explains one of the major differences between skiing and snowboarding, but is a cornerstone of modern snowboard technique.
This is the idea; a snowboarder can edge and pressure a snowboard using the common edge and pressure control movements, but they can also control the pressure and edge along the length of the board. They do this by using their feet, ankles, and knees independently from each other. Edge changes and adjustments to edge angle do not have to occur with both feet at the same time, the same is true for changes in pressure. Lets look at how we apply this to different situations and levels of riders.
Lets start with a basic heel side side-slip. If edge and pressure are held equal with both feet the board will slip straight down the fall line. If we change the amount of edge with one of our feet things change. If we edge less with the front foot, the nose of the board will seek the fall line and start to move down the hill. In a heel side slip it is like stepping on the gas pedal. Whichever foot you step on the gas pedal with that will be the end of the board that wants to find the fall line. This is significant in that this movement allows us to control the board and initiate turns without gross movements of our center of mass. We can stay balanced on both feet. In the old days we thought this had to be done with weight shifts from foot to foot.
When linking turns edge movements are initiated with the front foot and followed with the back foot. This allows us to start the turn with more pressure on the edge at the front of the board and finish the turn with more pressure on the edge at the tail of the board without disturbing our balance. Taken to the extreme we could even finish the turn on the back of the board while beginning a new turn on the front. This ability to twist the board gives us a wide range of options to control the pressure along the edge, and the best part is we do not have to mess with our center of gravity to make it happen.
Exploring this idea further, it is not even necessary that the back foot follow the movements of the front foot. The front and back foot can edge opposite of each other. This can be helpful when making very short radius turns, such as in the bumps or on steep terrain. The front foot can hold an edge while the back foot helps the board come around.
This technique is used by most top riders. It is used in a wide variety if situations with the only differences being in timing and degree of edging. In powder it is not really needed but does not really hurt either. For alpine racers with narrow boards and extreme stance angles it does not work because edge movements are more lateral, but for most of us this is the way to ride.