Any idea what Runna is Based on?

I had been using the app Runna quite a bit until I got more serious and read Daniel’s and Pfitz marathon books.

Currently still using Runna (kind of) to build into Pfitz’s 18/55 in December.

It got me thinking, what’s the philosophy behind Runnas training.

It seems kind of lower on the volume but higher on the intensity. There seems to be nearly always 2 workouts in the week.

A session around lactate threshold and then an interval type workout where it’s all out.

I used it for a half and hit the target it estimated but I felt like even the easy runs were a lot of faster days. More out of curiosity than anything.

I’ll probably stick to the 18/55 come marathon time even though Runna has marathon plans. The former just seems more tried and tested.