This is a quote from a research paper I found on Steve Magness's Twitter and the key part I've found is this section, which includes talk about Henrik Ingebrigsten from when he was considered a junior athlete.
HVLI = High Volume Low Intensity
[quote]
Irish runner Sonia O’Sullivan was the 1995 World
Champion in the 5000 m. In 1998, she won the long and
the shorter distance in the World Cross Country
Championships and became European champion over
5000 and 10,000 m. Between November 1994 and May
1995, O’Sullivan typically ran 160 km/week. The highest
volume reported for a single training week in this
period was 180 km. She typically ran two sessions per
day. During the competition period, the average weekly
training volume was reduced to 115–120 km/week.31
During the last three decades, international distance
running has been dominated by African runners. Billat
et al.27 studied the training program of Kenyan elite
runners during a training week in Europe in April
2002. In addition, the athletes’ training diaries over a
period of 8 weeks prior to this week were analyzed. The
sample (n ¼ 20) consisted of 7 women and 13 men. All
runners in the study had finished among the top 30 in
the Kenyan Cross Country Championships in 2002.
According to Billat et al.,27 these runners based their
training on either a ‘‘high volume and low intensity
model’’ (‘‘HVLI model’’) or a ‘‘low volume and high
intensity model’’ (‘‘LVHI model’’). Men (n ¼ 6) who
used the LVHI model ran 158 19 km/week and
women (n ¼ 6) who used this training model ran
127 +/- 8 km/week. Men (n ¼ 7) who followed a HVLI
model ran 174 17 km/week. These runners performed
10 to 16 running sessions per week during the reported
8–9 weeks.
The training volume reported for male HVLI-model
Kenyan male runners corresponds with the training
volume reported for the Norwegian female runner,
Susanne Wigene, who finished second in the 10,000 m
in the 2006 European Championships, running
30:32.22. In four different periods of the training year,
she ran an average of 160–180 km/week.24
According to Rabadan et al.,28 Spanish male middle
distance runners (n ¼ 40) at a national and international
level, during the period 2000–2008, ran 130–
140 km/week in the preparation period. During the
same period, male long distance runners (n ¼ 32) at
the same level, ran 160–180 km/week.
The average running volume for the 2012 European
1500 m champion Henrik Ingebrigtsen was 146 km/
week in November and December 2011, followed by
156 km/week during 10 weeks from 1 January to the
middle of March 2012, and 150 km/week from the
middle of March to the end of May.20
Training volume among young distance runners. A study of
four young Norwegian distance runners (age 17–19
years), who were second in the team competition in
the 2008 European Junior Cross Country
Championships (finishing 2nd, 10th, 16th, and 20th
place), ran in three different periods of the training
year an average of 132.5 (+/-25.9), 115.7 (+/-22.9), and
145 (+/-22.9) km/week.23 This is substantially more kilometers
per week than Esteve-Lanao et al.29 reported for
young Spanish runners over a training period of 6
months. These runners had an average running
volume of 70 km/week.
The primary distinction between the four Norwegian
juniors and the Spanish runners was the number of
kilometers run at a low intensity. In the study by
Esteve-Lanao et al.,29 it was found that the runners
who ran the most kilometers per week were those
who performed the best. This may be a contributing
factor to the fact that the Norwegians, despite being
younger than the Spaniards (17.8+/- 1 year vs. 23 +/- 2
years), performed better. The Norwegian runners
were closer to the world records over the distances
1500 and 5000 m than the Spanish runners.23 The two
juniors in the Norwegian study who ran the greatest
number of kilometer per week in 2008, three seasons
later (2011), became European champions for adolescents
(