To my mind the key difference here is the word 'race'.
Your body will definitely be stressed differently if it's spending a lot of time near (above/below) lactate threshold as might be the case in a long bike race.
In the cycling world that might be called power zone 4(ish).
You'll probably also have to throw in a number of VO2max efforts for small hills; zone 5.
In the case of hiking with a 20Kg pack, in a non-race situation, for 8 hours a day I would guess you'll mostly spend your time at a lower heart rate doing tempo work, which would mostly be zone 2.
This is somewhat similar to the long, slow, steady training winter bike training that was popular before current practices of interval based training became popular. It is designed to improve muscular mitochondrial density.
Another way to put it, if the through-hike had been a race against the clock the hiker might have been much more degraded by the end of the race because he wouldn't be able to pace himself the same way.
I'm not a qualified sports scientist so would very much appreciate someone with more knowledge than me clarifying or correcting anything I've written.
Your body will definitely be stressed differently if it's spending a lot of time near (above/below) lactate threshold as might be the case in a long bike race.
In the cycling world that might be called power zone 4(ish).
You'll probably also have to throw in a number of VO2max efforts for small hills; zone 5.
In the case of hiking with a 20Kg pack, in a non-race situation, for 8 hours a day I would guess you'll mostly spend your time at a lower heart rate doing tempo work, which would mostly be zone 2.
This is somewhat similar to the long, slow, steady training winter bike training that was popular before current practices of interval based training became popular. It is designed to improve muscular mitochondrial density.
Another way to put it, if the through-hike had been a race against the clock the hiker might have been much more degraded by the end of the race because he wouldn't be able to pace himself the same way.
I'm not a qualified sports scientist so would very much appreciate someone with more knowledge than me clarifying or correcting anything I've written.