The concept of starting turns fore and finishing aft is well known and it can be seen in many montages of racers that it is used very often. It also surfaced in the iconoclastic turn thread.
It has been discuss from time to time here on epic, but I don't think there has been so much discussion around the reasons for finishing aft.
A few reasons I can think of are
--The concept of crossing paths. When the skis cross the path of the CoM the skis they kind of cut in front of the CoM if they are still edge locked. If you keep the skis engaged during this phase it is unavoidable they they are loaded aft. Basically it allows the skis to be engaged in a larger part of the turn and the float comes quite naturally.
--Biomechanical reason. If you imagine a plane defined by three points, the center of the ankle, knee and hip joints respectively. The sideways bending moment in the knee is proportioanl to the distance of the force vector emanating from the ski and this plane. This means that if for example you are using pure knee angulation and the force vector passes through the hip and ankle there is no sideways bending moment. If you are very much forward towards the end of the turn, when the forces can build very quickly, it can be really bad for the knee.
--Retraction. If you are using retraction to finish the turn it is quite natural that the pressure moves aft, since the knee moves forward when you start to retract. If you retract fast this does not matter because then there is no load and hence fore/aft is irrelevant. However, in racing it is quite common to flex a little towards the end of the turn and knee-angulate, in order to kick-start the vaulting effect. This is easier if you allow a little aft, and it can also be biomechanically sound for the above reason.
--Bumps. This can be similar to the fore-aft shuffling you do in bumps (back-pedaling) but its a virtual bump. If you master it outside the bumps it comes quite naturally when you encounter real bumps.
--Rotation state. Since the force from the ski is no longer aligned with the intertia force (CoM..) the rotational state will change, and this can be used to your advantage.
--Pivot. If you need to pivot more than the inherent pivot (the one caused by the two paths in a fast transition) before the next turn, e.g. to drop some speed or other reason. If you are aft towards the end of the previous turn a pivoting will turn this aft state into CoM inclination, i.e. you will engage the next turn much faster than if you pivot from a centered state.
--Automatic turns. It can be used to initate a turn. Read all about it in the automatic turn thread.
Do you agree with the above reasons, and do you have any more reasons why finishing aft can be good?
Perhaps reasons why it can be bad?