I'm currently trying to run a fast half marathon, and if that goes well, plan to move up to the marathon.
I find it easy and feel like I get something out of interspersed progression runs over hills during the week (along with the occasional faster 10 miler over flat ground as well).
Currently, I'm mainly just doing progression runs (over flat ground and rolling hills) along with a long run a week. However, I feel like I should start adding in some workouts if I want to race well/mimic some race pace work. Would one fartlek type workout a week (3 min on, 2 min off, 5 min on/5 min off, etc.) be enough, along with progression runs and a long run? Right now, if I'm feeling good, most of my runs are progression runs where I pick it up after a few miles and finish fast.
I find it mentally easier to do these (as well as non stop fartlek workouts on occasion), but would it be worth it to include specific interval workouts? Or can I build enough strength with these workouts (running 80-100 mpw with doubles)?