Originally Posted by Ghost
Just for the record, although I've been stuck in the land of small hills for a while, I've also skied both east and west; Tremblant and Jay Peak (EAST) are also about 2100 vertical feet, and I've skied both many times at just about as fast as they can be skied, and never felt the need to stop halfway down. I've never felt making it to the bottom was an a challenge. I am genuinely curious as to what the failure mechanism is, for folks who need to stop in the middle of a run. The resorts provide chair lifts for resting. It don't take that long to get to the bottom. Why would you need a rest so soon?
I find it depends on the group. Sometimes it's social as was noted above.
Beyond that, I find those who don't ski as well tend to need to stop more. Probably because they're fighting the hill vs skiing it (the psychology that Bud talks about in TAPP thread).
And then for some it's a fitness thing of course.
Personally I have no trouble skiing top to bottom at Tremblant when I'm skiing cruisers, but I tend to ski bumps as much as possible. I'd bet that I'm in as good or better shape than most, but I can't ski Expo top to bottom all day. I can for a few runs but then I get tired. Now I do view bumps as a more anaerobic version of skiing - much like people can't sprint forever.
I do agree that there is an endurance element to skiing, and mountain biking is a great way to fill that part of the need - it's got a great combination of bursts of effort with a long sustained effort. But it's only part of optimal training. You need strength. You need power. You need mobility. If you were going to do just mountain biking as training, and then go into lots of days on snow in the winter then do yourself a favour and make sure you are getting some hip flexor and pec stretches in as well as some upper back and glute work, because you're spending a lot of time in flexion, which is not a nice way to treat your back, hips and shoulders. This is even more important if you also have a desk job.
Inline skating is also a great tool to get the endurance/energy system development for skiing, and works the glutes nicely as external rotators, which is ideal for skiers. But again - adding some a base of strength is always a good thing. If you were going to pick a single strengthening exercise to do, deadlift. Just make sure you do it with good form. It doesn't have to be crazy heavy.
One last thing - here's a nice little warmup exercise that I love for skiers - it's a progression of a single-leg Romanian deadlift with added hip flexion and external rotation and a nice balance element: