Their knees are not as sore and hips don't bother them as much, whatever muscle functions they used to keep the ski carving are now being done by the increased side cut and shorter length of the ski. Intermediate skiers who are stuck at that level can turn easier and improve their ability faster with the deeper carving action that shape skis can provide. Many experts initially resisted the shape ski, but are now realizing that these skis can do things that their old skis just couldn't. This is evident in the fact that World Cup ski racers are slalom racing in 170 cm skis. This was unheard of even five years ago.
All skis have had some shape but the new breed of skis has more.
The shape of a ski is basically the difference between the width of the ski at the tip, the waist, and the tail. This shape is commonly referred to as side cut. One of the biggest misconceptions is that shape skis are the same. This is definitely not the case, since shape skis come in many different dimensions. The trick to getting the most out of these new skis is to pick a ski that has a shape that will lend itself to improving your technique, considering the terrain and your style of skiing.