Originally Posted by tdk6
So what you are saying is that to increase speed we can use the trampoline turn and when we simply want to keep our tracktion we use a retraction turn.
This sounds good. However, correct me if Im wrong but wether Im skiing on a race track or outside the gates I have no problems keeping my speed up. Very seldome I need to gain more speed. To me skiing is more about slowing down. Good edging technique and straighter line serves for speed while brushing/skidding/steering and rounder line serves for maintaining speed or slowing down.
Can it be that the increased tracktion as the pulse hits the snow is what matters and to achieve this you can approach the task two ways: the trampoline turn or the retraction turn.
The retraciton turn transition fuels on the puls that is a result of skis turning and turn forces building up. The trampoline turn again creates the puls with a man made muscle effort.
Ultimately a good skier should be able to perform both I think but which path serves for a better learning path? Pros and cons of both? Also consider other skiing than purely carving.
If you're racing, it's more likely you'll be looking to increase speed. If you're free skiing, there are more times that you'll be looking to control speed.
Within both of these generalizations, there is lots of room for variation. In a race course, a racer may want to generate lots of speed, but skill and strength factors may limit what is actually achievable (and the course set may influence what is advisable). When free skiing, a skier may still be looking for opportunities to drop into the fall line and accelerate.
If you focus on the biomechanics, a trampoline turn and a retraction turn have a lot in common.
There are two critical differences which determine whether your outcome is more speed or less speed: timing and amount of force.
1. Timing: when do you flex, and when do you extend, relative to your position in the turn and relative to intended direction of travel? Flex up to the apex of the turn, and extend from the apex to be able to generate the most speed in your new direction of travel. Continue to flex right through the apex of the turn, past the direction change, and you will have absorbed and dissipated much of the energy carried into the turn, and consequently dumped speed along the way.
2. Amount of force: how much do you flex, and how strongly do you extend? Flex just a little, and you don't have as much range to extend, and you won't have much force to add to the turn. Flex more deeply (but not too deeply of course) and you'll be in a position to push back strongly with your extension to gain speed. If you extend more slowly, the energy dissipates and the direction change drops your speed. Or, leave it in the middle -- just enough force to maintain a consistent speed.
Thinking about the trampoline analogy again, dropping down low, and then pushing up strongly when the trampoline is at its maximum deflection is how you get the most height. This corresponds to increasing your speed on skis.
If you keep flexing, past the maximum deflection of the mat and on the way up again, then your flexing is absorbing energy and your height reduces. This corresponds to decreasing your speed on skis with a retraction move.
I'm thinking of this in a carving framework. If you bring in skidding, that's just another way of dissipating energy and ultimately reducing speed. The impulse effect is still there, but the skidding adds another limiting factor.