Running and cycling use technology but an old school log is the best. Yes my fancy watch paired with my phone can tell me my heart rate, pace and max speed but it doesn't allow me to put in my mood. Do I run better on days that I don't have to work? What about my blood sugar, do I run best when my blood sugar is in or out of range. I can also keep track of my resting heart rate and how I slept the night before. All of this may seem like over kill but I believe this is the best way to approach training for the next race I have no matter the distance.
When I ran the New York City marathon in 2013 I was prepared physically but not mentally, when I ran my first 50k a few months back I felt I was prepared mentally but not as much physically. I'm hoping that a running log will help me be ready both mentally and physically.