On Fridays, I'll do a short outdoor run (three to five miles) or take another indoor treadmill class. In addition to Precision Run, I sometimes take a class at Mile High Run Club. It's a similar class format with intervals of inclines and speeds. I've been taking the High 45 class on Fridays, which is 45 minutes. And while 45 minutes can seem boring on the treadmill, the intervals make it go by fast. I usually clock around 3.5 miles during a High 45 class (there are plenty of walking breaks throughout). There are also outdoor run groups organised through Mile High Run Club, which I haven't joined yet but plan to.