Adapting Norwegian Singles for a 50k ultra
I've not seen many reports about Ultramarathons using this approach, so here's my contribution!
Background: I have been using the NSM for about 18 months, but after about the first 6 months had stopped seeing improvements due to what I subsequently discovered was a pretty severe iron deficiency. I started taking iron in December, and set my eyes on a 50km with 1800m vert in May.
Training: As it’s not that much further than a marathon, once I was 12 weeks out from the race I started using the special marathon block, I adapted it to include one uphill treadmill session per week, where I would do the 10 or 12 minute intervals at 8% gradient and to HR instead of pace. About 1 month out I switched this to be a stair-stepper session with a weighted vest, to get some race specificity. My easy runs were almost always on the trails, my other Sub Threshold sessions on the road.
I initially planned on extending the long run out to 3 hours, but in the end, barring one 6 hour run that was a bit of a social excursion at easy pace, I kept the rest of my long runs to 2 hours. I felt comfortable doing this as I'm familiar with the distance already, and felt extending them was taking too much out of me for the rest of the week.
I also added strength training twice per week using the Tactical Barbell operator program - this is 2 sessions each covering squat, deadlift, chest press and pull up. I found this to be a good compromise - I knew I needed some strength training so my legs could handle the hilly terrain, but found leg specific sessions too fatiguing when combined with 3 running workouts per week.
Result: Overall, it worked really well. I finished in a bit over 6 hours in the top 15% of women and was able to maintain a decent pace at the end, rather than fading in the second half.
My weakest point was probably the technical descents - not something I can easily practice where I live, but doing some interim fell races would have helped me with that.
I also found some of the long rocky flat-ish sections a bit slow going. In retrospect I’d have kept up the uphill threshold sessions right until the end of the block, and perhaps switched out a flat sub-t for the stair-stepper in the last month instead.
So in summary, although the technical mountain running skills are things which ultimately need practice, the NSM marathon plan worked really well for building up the endurance on the flats and uphills that I needed for a 50k race. The load felt very manageable and I was really happy with the result.