MOD NOTE: The following post and its replies were split off from another thread as a tangent discussion.
Interesting issue, which measure of physical fitness best correlates with skiing performance. Maybe we should do this here.
I can say this: Elite skiers - have talked casually to a couple of U.S. Ski Team members and have done some research - spend a lot of time doing stuff like squats, box jumps, eccentric movements, foot work. Eg, anaerobic work on explosive movements. Yes, core strength is part of their cycle. But in all honesty, they already have that covered or they wouldn't be there. And obviously, they replicate their race day movements by skiing most all year round.
OK, we are not elite skiers, by a long shot. So does that mean we all need more core strength and aerobic conditioning? Maybe. In fact, no doubt if we want to live long and prosper.
But here's a couple of things: First, specialists are falling out of love with "core strength" as a universal solution for sports performance even as gym trainers have made it their mantra. New research indicates that habitual replication of movements involved in the sport itself, e.g., practicing the sport, or segments of the sport, produces better outcomes than just taking care of "the core."
Which incidentally is not particularly associated with crunches, even oblique crunches. Most of us here have soft bellies, but it's not killing our turns. Just our hearts. Better to work on our erector spinae and psoas major and multifidi and gluteus medius and small muscles of the pelvic floor. A bosu ball and some planks and Superman postures would seem to do a lot of the trick, then throw in some squats.
Not arguing that core strength is a bad thing, it's a great thing. But concentrating on it may be more about look after other issues than about getting better as a skier.
Second, the impact of different exercises depends on our level. A middle aged intermediate may benefit more from core exercises than a middle aged advanced. Put another way, if you're advanced, your core is probably good enough for skiing, at least. Just like a member of the US Ski Team is not going to gain much from extra running or more box jumps. They're already really really good at that.
Third, alpine skiing is not an aerobic sport. Sorry. I know many of us get winded, especially if we race. That's another issue, probably also related to our hours per day of sitting and our risk of heart attack. But any sports physiology text of the last 50 years will show that while Nordic is probably the most aerobic sport in existence, it doesn't rub off. We're down there with tennis and other moderate MaxVO2 activities. (By way of explanation, MaxVO2 is the amount of oxygen, in liters/kg body weight/minute, we can use. Sports that are continuous, not intermittent, and use more total muscle groups have the highest.) So while jogging or treadmills or otherwise building up our aerobics will probably improve beginning and intermediate skiers, it will have less of an effect as our skill set improves. Which will, of course, allow us to use less energy while skiing.
Last, I didn't show and tell about my presses to suggest it was the definitive measurement. Or that I was exceptional. I'm sure many here do better. And maybe a shuttle run would be more telling. Or squats instead of presses. But I'd guess that a difference in slope performance would be more about legs than other parts of the body because of what we don't notice more than what we do. We won't notice our thighs being so toasted at the end of that mogul field that we're losing form. We won't notice fall offs in our abilities to maintain steady edge pressure after lunch.
Metaphor time: I was struck by grainy black and white videos I saw last night of Ali in an early fight, right after he won Gold and went pro. The first 3-4 rounds were just him jabbing at the other guy's head. Over and over, almost casually. Rarely the body. That straight long jab that opponents said looked innocuous but was like being hit by a piston, over and over. As Mailer said, a "surgical attack." Along about the fourth, his opponent began to act subtly different; his counters were not as crisp, his reflexes were blunted, his arms were beginning to look awkward in the breaks after the clinch. So Ali would do that thing those of us who are old enough will remember. He would put his gloved left hand on the head of the other guy, like he was testing the dough. Leave it there for a second. Assaying concussive damage. Then he would speed up. By the 6th or 7th, the referee would stop the fight with a TKO; too many of those jabs were landing too easily. He did it the same way against Foreman, incidentally, same gentle patting with the jab hand when he came off the ropes, finished with Rope-A-Dope, and started landing big counters.
So for me, that's what legs are all about when I ski. (And to extend the metaphor, Ali always said that his power really came from his legs; recall he used to train hip deep in swimming pools.) I'm an old guy, can't get in shape quickly. Unless I do those presses and squats and and hikes in the summer and early fall, I spend the winter slowing down in the fourth round, almost insensibly, working harder and harder to do the same thing that was easy in the first round. And that's when my back begins to hurt, incidentally; if my legs are getting tired, I compensate by too much lean, too much upper body compensation.
YMMV, and I'm sure it does.