I spoke with the rep for skier's edge at the ski show last week. They've always intrigued me and so I stop by and try it, and then see the price and go home and jump over boxes.
They have a new attachment called the QS5 and it is a U-shaped rail that clamps onto the rails that are there. It also involves a new carriage. It makes the machine virtually silent and extremely smooth from side to side. It's a definite change and upgrade.
Whether you use poles or that bar he would tell people to start like this: stand in the center at the top of the bump, now tip your feet from one side to the other gently and shift your balance gently from one foot to the other as you do it. You should be slightly flexed as you do this. As it starts to rock from side to side keep flexed so your body stays relatively centered and the legs extend as the carriage rolls back and forth under you. At first you can allow your body to travel with the carriage a bit so you build some momentum. when you really want to burn your legs up, see if you can keep your body and hips centered and let the legs extend rapidly out, then back in as you flex, and then out on the other side. You can counter balance over the feet if possible, but the legs will be flying back and forth and the torso is calm and stable. think of keeping your belly button in the same place. You may have to pick up the pace so that the legs are able to extend and retract quickly, or the body will ride along on the carriage from side to side. (doing that simulates the larger radius turns.)
For another challenge, do it on one leg, side to side. The switch legs after awhile (I imagine it won't be too long.)
It really does burn your legs and get you panting quickly. Let us know if it affects your skiing and stamina.
have fun,
Icanski
ps, you can probably order the CD from them and they may even have an online demo you can watch.