Note to reader: Question edited for better clarity.
Hey Wyatt, I'm training for my first 100-miler in June and am curious about your thoughts on volume versus quality as I know you've experimented with both approaches. Do I need to run lots of miles or will quality with some long runs sprinkled in do the trick? - JL
Great question and one I get quite a bit, which is why I've decided to post this question and my answer. The short answer is, there's no one specific approach to training for a 100-miler that works for everyone. There are some tried-and-true elements of training for 100s, such as the long run, but by and large what you do beyond that comes down to what works for you and only you. And you need to tailor your training to the specific challenges of the race (mountains and hills v. flat, trail v. pavement, cold v. hot, altitude v. sea level, etc.). If you're training for Rocky Raccoon, there's not much need to hit the mountain trails. If you're training for Hardrock, you're not doing yourself any favors training on a sidewalk. You get the idea.
I know guys who have trained for and won 100-milers running 140 miles a week with a ton of quality (track intervals, tempos) sprinkled in. Mark Godale comes to mind. Back in his prime, the dude would crank out 5:20 mile repeats and killer tempos every week, all while doing doubles just about every day (an approach I took in 2008 and 2009 and it seemed to work for me). I know guys who have trained for and done well in 100s running half those miles. Lucho comes to mind, though know that Lucho built a huge base over a period of several years as a professional triathlete. And, though I don't know him personally, I have heard Bob Africa takes a less-is-more approach to big undertakings like Leadman.
I have done well in 100s after running 100-110 miles a week for weeks on end (Burning River 2007, Mohican 2008, Mohican 2009). I have run 100+ miles a week training for a 100 and not done well (Leadville 2010). I have tried lots of approaches over the years, rationalizing to myself why each should work, and experienced varying results. Lately, it's mostly been mediocrity. What I have ultimately come to realize for myself, based on trial and error, is that I thrive on volume. I need lots of mileage and tons of aerobic work, with some quality like tempos and hill repeats every so often (a few times a month) just to stimulate different systems. Big volume pays off for me especially in the latter miles of 100s. The best race I've had in a few years (Leadville Marathon 2013) I came into having mostly run in my aerobic zones, with some fast stuff here and there (mostly fast finishes), for the previous two months. The reason I didn't break 20 hours at Leadville in 2013, or come damn close to it, was that my stomach went south and my ankle was still jacked from an injury. But I am convinced that the aerobic stuff I did all summer had me in amazing shape when I lined up for that race.
Anyway, the key, I think, is to listen to your body and train as hard as you can without breaking yourself down. Getting to the starting line of a 100-miler healthy is half the battle. So, if you need it, take Monday off after running 40 miles over the weekend (just an example). Don't feel like you have to go out and grind through the mileage day in and day out even if you're feeling horrible--and definitely don't do fast stuff or go super long if you're feeling crappy (been there, done that and it's a road you don't want to go down, especially when you're old like I am). The key is to adapt to what you're doing with your training. Just remember that your body will tell you how it's responding and rest is how your body gets stronger. The gains come not when you're piling on the miles but when your eyes are closed and you're asleep. You run 30 miles and then the next day you rest/do light active recovery stuff so your body can recover and make gains from those 30 miles. The same goes with tempos, hills, intervals, etc.
As far as quality, I believe quality and volume are what make a great marathoner. I've long been skeptical of quality's helpfulness in training for 100s. But it depends on how you define "quality." Anyway, in 100s, you're mostly aerobic (zone 2, maybe even zone 1). If you "go anaerobic" in a 100 for a long period, that's not good because it'll result in muscle breakdown. You need to stay aerobic and burn fat in 100s. So it makes sense to me to do most of your training in an aerobic, fat-burning state and get super efficient. With that said, I'm not convinced long tempo runs of 12 miles at 6:30 pace (just an example) really have a big payoff in 100s when that pace may be twice as fast as what you're doing on race day. Sure, long tempos will help with strength and speed (huge in the marathon) and they'll induce some adaptations, but in 100s you're running significantly slower, so why not log most of your miles at that pace especially when it's inducing fat-burning--which you need when going the distance? Don't do everything at aerobic effort--you'll go stale--but aerobic efforts are the bread and butter of your training.
In conclusion, to succeed in 100s (and it feels strange to me to be giving this kind of advice when I have a checkered recent past as far as 100s), I think you need to be aerobically fit and efficient and have logged a handful of very long efforts in the neighborhood of 30+ miles with maybe back-to-back 20s run at some point. Log most of your miles in an aerobic state. Do tempo runs, intervals, fartleks, fast finishes and hills a few times a month (but remember to train specific to the course's challenges) to keep the adaptation process going. But the bread and butter are those aerobic efforts. Just know that stress and niggles are to be taken seriously. Stress of life, work, family stuff, etc., doesn't get talked about nearly enough but it will hinder recovery and undermine the quality of your sleep. Sleep is huge, as evidenced by elite marathoners often sleeping 12 hours a day. So if you have a super-stressful week going, maybe back off the mileage. And definitely listen to the niggles--ice them, massage them, rest them.