SherpaJim,
As a conditioning specialist, I recommend that people do weighted hiking (or, in your case, weighted stair climbing work) 1-2x a week, but since you have not had any knee, ankle or hip problems, you might try the following for variety (and to challenge the muscles differently, to prevent any overuse injuries and keep your workouts fresh): 1) 1x/wk, do stair stepping (machine) with 40-50#; 2) 1x/wk, go outside to a steep hill and climb it (up and down, for intervals) with your weighted pack; 3) 1x/wk, go on a distance hike over more gradual terrain (longer than 45 minutes if you like, e.g. on weekends, and heavier if you like). That gives you the 3 times a week for endurance pack work. I'd also vary the weight, particularly in the off season, then ramp back up to the 50-60# closer to the time you'll need that particular level of endurance. That will give you more variety, recovery time, and also free up more time to do other things -- like get ready for ski season, for example. As always, if you begin to feel any strains in ankles, knees, hips, or lower back, then back off on the weight, frequency (maybe 2x/week would be optimal) or distance. Happy training!
Courtenay Schurman, CSCS
