I had a great experience with EIM running solid races from 5k to 10k. I eventually drifted away from it because of a chronic injury that makes it difficult to run fast every day. However to answer your question, both EIM and Norwegian method share an (1) emphasis on quality volume at relaxed efforts, (2) focus on raising the anaerobic threshold, (3) development of running economy and reactivity as Klaas puts it, and (4) using a small amount of hard anaerobic work to sharpen for frequent racing.
They differ in…
- Modulation… the Norwegian method stacks the quality on 2-3 days per week with easy days in between. The quality days often have two sessions in one day coining the buzz phrase “double threshold.” EIM can also have double days for advanced athletes.
- Total volume… there’s a lot more easy running in the Norwegian method that can get to 100+ miles per week. I was in the 45-55 range on EIM.
- Workout design… while the intensities may be similar. The sessions in the Norwegian method have significantly less rest and higher volumes.
- Lactate guided… the Norwegian method encourages frequent lactate testing to control intensity while EIM uses effort, HR or power (stryd).
Bottom line… I think EIM is more realistic for most people due to the lower training volume! However, I think the Norwegian method may produce better fitness due to volume, daily modulation, and shorter rest bouts during the sessions. Now that I am healthy again, I am experimenting with a compromise between the two with 3-4 quality days per week at relaxed intensities (shorter rest) and a few easy days in between. Instead of the double runs in the Norwegian method, I use cross training to reduce injury risk!