This morning I bagged one of my local favs....Grotto Mountain. Well, technically I didn't get to the total top, just the false summit. It's where I generally go. From the Alpine Club Canada clubhouse it's a major vertical climb. much of the hike is serious steep. It's good training for rando racing bootpacking because of its equivalent steepness.
A hike such as this without poles would be much harder....both up and down. Going up I generally double pole it really leaning over and reefing on those poles. On the descent it keeps your speed in check and is a good back up in case the ankle starts rolling over.
A friend recently commented that he couldn't bring himself to run with poles after observing all the "Nordic Walkers" at the ski hill where he works. Granted, the new fad has its fair share of "cherry pickers" (those that really aren't using the poles but pluck them ahead anyway), but the guys that do it right really use their arms.
Here's a video of some jr. athletes bounding....some good, some not so good: http://www.youtube.com/watch?v=shmGa1XgPh8
The bottom line is that xc & skimo are quadrepedal sports, using all 4 limbs. As such, it places a higher demand on the cardio system (why xc skiers record such unworldly VO2 values). So we've got to train this way.
While in line for some lunch in Italy for the skimo Euro champs last year Dave D. and myself talked a bit to the Austrian delegation leaders. One of them commented that they used to just mountain bike all summer, but with their new coach- a former nat'l team xc skier, they were radically changing things. Mountain biking has a couple of serious limitations. First, it's not quadrepedal and second, it's not weight bearing. In the 80's a few of my xc friends would bike a lot, but take their saddles off (making it weight bearing). It was a whole new workout!!! Try it, you'll see the difference (just make sure you don't mistakenly sit down onto the seat post....ouch!!