Skating is so hard, after an hour of skating my g. maximus, g. medius, and hamstrings are just thrashed. Skiing hard for more than 10 minutes consecutively is quite possibly on of the most taxing things I have ever done. After and hour of skating I am fatigued, but satisfied knowing I "did something." I am always impressed by the winter biathletes. They ski around the course at what I am guessing to be between 80 and 90% of their max heart rate and then have to stop quickly and shoot 5 targets with a racing heart. Winter biathlon is insane, it't insane to go from an aerobic activity (skiing) to a tecnhical skill (shooting) it's really an amazing sport to watch. I have had some luck being able to ski without aggravation to my illiotibial band so I plan to emphasize that over the winter months and hopefully kick the itb soon.
Last year I built up to 2 hours and 45 minutes of skiing in one session and I would like to hit the 3 hour mark this winter. I figured that would pretty much thrash me as much as the long brick workouts that I cannot complete currently.