I have a question for all of you experienced ultra runners out there. For years in my training I have used a rest week in my training. My current schedule has me building for 3 weeks and the 4th week is my rest week. On my rest week I cut my highest mileage in 1/2. How many of you out there do a rest week? If so what do you do? Also I am using my rest week as a rest from running but not training. I am currently filling in the extra time with cross training activities like more biking and skiing. Does this negate the purpose of the rest week? Should I be decreasing my actively overall not just my running. Thanks for the input.

I usually cut back to about 50% of my average for the cycle... usually 4-5 weeks on, then a week 'off'. My training is pretty unscientific though, I mostly just run when I want (and pick runs that sound interesting) while trying to follow some rough training guidelines. If somebody is putting on an interesting group run that happens to fall on a rest week, I'll do it anyway and rest the following week, etc.