Originally Posted by CTKook
Uhh...again, no. It does not depend on where and what you ski in the way you think. Taking as a given that you obviously ski super-gnarly stuff, the balance involved in, say, recovering on one ski is different from the balance involved in balancing on one foot in sneakers. The balance involved in, say, skating on one inline skate can be pretty similar, which is one reason why good skaters, although they still need to learn to ski, can cross over more quickly than most. If you were saying you went to a tramp gym, or a specialized facility like Woodward at Copper, to work on body awareness while in the air, then yes that transfers well, as well. Even for unpredictable cliff drops and such, since "variable" drops seem to be part of your skiing day.
I think you're mixing up practicing your skill with physical preparation. Skill is of course a huge component of what we do in a sport like skiing. And it is largely what determines who succeeds and who doesn't.
Physical preparation helps those with skill to be able to keep exhibiting the skill. This is why most top athletes in most sports spend time in the gym preparing for their sport. There are performance benefits as well but injury prevention/risk reduction is the bigger reason. Career longevity is another way to look at it.
For those with less skill, physical preparation can also help hide some of what's missing. But improving skill will do so as well.
For all, proper preparation can also help to reduce the time it takes at the beginning of the season to adapt to the demands of skiing. Strength, flexibility and power training (including plyos) are critical for this. The fourth piece of the puzzle in terms of physical preparation is conditioning. That's what allows you to potentially ski all day without getting winded. This can be accomplished in many ways, including running, biking, and skating.
I would agree that mountain biking and skating also help train for the skill of skiing in addition to conditioning. But they do not fit the bill in terms of strength power and flexibility.
PS - a little clarification on what constitutes a plyometric: technically plyometrics are movements that are pre-loaded. Typically they are jumps (2 leg), hops (1 leg to same leg) or bounds (1 leg to opposite leg), but there can be upper body plyometrics as well such as plyo pushups and medicine ball throws. Some movements are referred to as plyos but actually are not. Hopping onto a bosu is not technically a plyo, unless one is hoping on and off again with no delay. I am guilty of misusing the term plyo as I use the term for hops where my client must stick the landing before doing another. I refer to it as a "phase 1 plyo" and do it to work proprioception (balance), but in all honesty, they are not plyos: they are hops. Continuous hops would be plyos.