I started doing MAF with Jeffing, then the last 2 runs I ran straight through, keeping my heart rate between 110 and 130. The MAF with Jeffing was a better pace, but it could have been a number of other things. I did my first trail running using MAF. 6.2 miles around Cooperβs Reservoir in Sutherlin ,Oregon. It was beautiful. Iβm not sore or tired, didnβt need a nap, and Iβm still up at 11pm! Iβm excited about this.