I have always done most of my miles on the roads/railtrail/smooth surfaces, but I've been thinking about experimenting on the trails. I have done some trail running in the past, but in my area the trails are pretty darn technical (single track, rocky, uneven). My pace is dramatically slower on these trails, but I'm wondering if there is value to me doing a portion of training on them. I typically train between 6:40-7:20 on my regular runs, but I'll average like 9:00 miles on the trails.
What I've considered doing is leaving the Garmin at home on trail days, and running by time/effort. So, if I want to get 8miles for the day and that would usually take me 55-60minutes, I will just run for 55-60minutes even though I know I won't cover 8 miles on the trails and just hope I'm getting the same aerobic workout.
Are there any opinions out there on this?