Better Adventure Training, Part 2 – Base Endurance

Base Endurance. The key input to success as an adventure racer. No other effort requires as much time, no other effort generates as much benefit. Adventure racing is an endurance sport and as such, excelling at it requires that you be a great endurance athlete. Let’s define what I’m talking about when I say “base endurance”.

Base – Cornerstone, fundamental, elemental. Upon which all other things are built. Think of the Biblical parable of the house built on sand and the house built on stone – one washing away, the other remains indefinitely. We want to be made of stone, unbreakable and everlasting. To achieve such a strong foundation, we’ll have to put in a lot of work in order to achieve an effortless level of high aerobic function.

okay, granted, she’s singing about “bass” not “base”, but it’s close enough

Endurance – The capacity to continue. Keep going. Persist. Try and try again. Not quit. Many people hear “endurance athlete” and in their minds, equate that to being something who excels in aerobic physical exertion. Having excellent aerobic fitness is certainly a large part of endurance, but it isn’t synonymous. There’s more to endurance that just having the ability to shuttle oxygen-rich blood to your muscles. There’s a skill part and a mental part as well. The skill part of endurance is the application of your excellent aerobic fitness to the sport in question. You can have good aerobic fitness by Jazzercise (but…why would you ever want that??) but when you smack dab in the middle of a 72-hour AR, it makes a whole lot more sense to be able to comfortably mountain bike for hours on end. The mental aspect is the psychological capability to keep going, to not slow down or throw in the towel.

That probably sounds a bit intimidating. But let me ask you this one question:  Are you a human?


Fantastic, you’re already pre-disposed to be a fabulous endurance athlete. We are tailor-made to move long distances at a steady pace. Our feet, with their high quantity of bones and high density of muscles, are designed to accommodate tremendous levels of shock from striking the ground repeatedly (i.e., running). Our (mostly) hairless bodies work like a giant cooling system, letting us shed excess heat generated from exertion in the form of sweat. Our cardiovascular system is built to pump enormous amounts of oxygen-enriched blood to farthest reaches of our musculature. And we carry tens of thousands of spare calories on our bodies in the form of fat cells. So trust me when I say that we’re all born for endurance excellence. The trick is just getting out of your own way so that your body is maximized at it.


this guy is 44 years old and just led his team to a crushing victory at the AR world championship.
this guy is 44 years old and just led his team to a crushing victory at the AR world championship. Damn.

Let’s talk about some of the critical factors that differentiate the pros from those of us who are…um…not quite at the pro level (…cough). To better understand what makes me not as good as someone like Ian Adamson or Nathan Fa’avae, we need to take a look a what makes someone at endurance, which means we need to understand energy systems.

Speaking broadly, there 3 three systems through which the body converts stored energy and uses it to power effort. These 3 systems, or pathways, are ATP-phosphocreatine, glycolytic, and aerobic/oxidative. The body utilizes all 3 systems all the time but shifts the degree to which a system is dominate based on the type of demand placed upon the body. ATP/PC is for high-intensity efforts, typically 10 seconds or less. Glycolytic is the middle road, covering efforts that last from 10 seconds to at most 2 minutes. Oxidative covers everything longer than 2 minutes. Let’s use a few popular Olympic sports as examples to better illustrate.

ATP/PC = 100-meter sprint, throwing sports (javelin, hammer, etc.), jumping sports (long jump, pole vault). Sports that demand 100% effort instantaneously.

Glycolytic = 800 meter sprint, 100-meter swim. Sports that demand a very high output longer than you can hold your breath, but over in 2 minutes or less.

Oxidative = Marathon, soccer, hockey, handball, cycling, literally just about everything. Sports that aren’t over in a few minutes, long duration, repetitive efforts.


human metabolic energy systems by subset. Credit Ideafit

So you can easily see that when a sport like Adventure Racing requires its athletes to race for days on end, we’re definitely in the aerobic/oxidative pathway. Our versions of a “sprint” is a race that only last 6 hours. But there are some important caveats to know before you get all excited and ignore sprinting for the rest of your endurance career.

  1. All 3 energy systems are always playing a part. It just varies in the percentage that the system dominates. So if you’re doing something like a power clean or 100m sprint, you may be 80% ATP, 10% glycolytic, and 10% oxidative. But if you’re hiking up a steep hill for an hour, it may be more like 70% oxidative, 20% glycolytic, and 10% ATP. The important thing here is to remember that you cannot exclusively train oxidative despite it being the dominant energy system for adventure racing. You’d be leaving 30% of potential energy on the table.
  2. You’ll often find yourself having to switch from oxidative to the other 2 systems as dominate when the time calls for it. Ever found yourself pulling your teammate up a hill because they’re too weak to continue? Or hauling ass away from a particularly nasty wildlife encounter? Or just going hard as possible in an all-out sprint because it’s neck and neck with another team? We’ve all been there, and in order to get better at adventure racing, you’ll need to fully optimize ALL 3 energy systems.

Endurance athletes must endure. To do so, we spend the large majority of our time in the aerobic/oxidative phase, both in racing and in training.

Becoming as effective and efficient as possible in this energy system is the holy grail of Better Adventure Racing.

Races aren’t won by the best sprinters, no matter how fast the leaders go at the start of the race. A navigation error can easily surpass the total amount of time you spend in a race with ATP/Creatine as the dominate energy pathway. Making yourself the most effective and efficient athlete in the oxidative metabolic pathway is the core input for improved performance. Mic drop.

wait, I'm not done yet, come back!
wait, I’m not done yet, come back!

A good analogy that I’ve heard in various versions is that of an engine. If you think of your body as a car and your body’s energy conversion capability as the engine (aka your metabolism), then you can imagine that the 3 metabolic pathways each representing a portion of the 8 cylinders. ATP is worth 2 cylinders, glycogen is 3 cylinders, and oxidative is 5 cylinders. When you put the pedal to the floor to accelerate as fast as possible, you’re telling your engine to use all 8 cylinders, maximizing the energy expended in exchange for top speed and acceleration. But when you’re just cruising, you’re just using 4-5 cylinders, as maintaining a constant speed and not needing to accelerate your mass, so you don’t have to burn a ton of energy. Here’s the critical thing – whether you’re cruising and only using 4 cylinders or hauling ass and firing on all 8 cylinders, those 4-5 oxidative cylinders are always being used.  They are your workhorses, and therefore, the quality of those cylinders have a tremendous impact on the ability of the vehicle (that’s you), far more than those 2 ATP cylinders that only get used on occasion. So where are you going to spend your time training? Pretty obvious that the best return on investment is the ol’ slow and steady oxidative.

How do we get better then, now knowing what it is that we want to get better at? By following the principles laid out in the first article (AR-specific training, Minimum Effective Dose, Healthy Until You Can’t, and Stay on Target) while we go out and train. Luckily, there’s already a popular training methodology that dovetails quite nicely with our BAR principles. Enter the Maffetone Method.

The Maffetone Method, named after Phil Maffetone, endurance physiologist extraordinaire, can be boiled down to a simple equation that allows you to calculate what’s called the “Maximum Aerobic Function”, or MAF. It is 180 – Your Age. Then add 5 if you’re in great shape without injuries in the past 2 years, subtract 5 if you’re coming back from an injury, and subtract 10 if you’re on prescription drugs.

Me as an example: 180 – 32 = 148 +5 (good shape, injury free for 2 years) = 153.

That number is my MAF threshold. Now whenever I train, I don’t (or at least try my best) let my heartbeat exceed that number. It’s that simple. Perfect? No,  but it’s a great general guideline that enables everyone to draw a line in the sand and say “no further”. For me, 153 represents that absolute maximum my heart rate can go before I’m crossing over into destructive quasi-anaerobic training that only hinders future progress known as the “Grey Zone”, “Black Hole Training”, or “Junk miles”.

Grey zone training is when you’re pushing too hard to recover adequately in the normal time frame (24-48 hours) but not hard enough to spike the body’s cortisol and create a cascading effect of super compensation. It’s like a luke warm workout, and it’s a total waste of time. Avoid at all cost.

I measure how good my aerobic function is by conducting a “MAF Test” every month or two. The MAF Test is a 2-mile run for time while at my MAF threshold. In my last MAF Test, I averaged a 8:10 mile over the 2 miles, which is respectable, but not nearly as good as I want it to be. The goal is to get faster and faster all the while staying at or below my MAF. This is the clearest measurement that my body is adapting and becoming better at aerobic efforts.

By setting an upper limit to my exertion during a workout, I prevent unnecessary stress from entering my body. MAF lets me continuously get into the “zone of discomfort” I discussed previously while not going too far into the pain cave (aka junk miles). I’m able to accumulate slight amounts of stress to my body to encourage it to continue to adapt and improve its aerobic function, without going too far and hurting myself. And to be sure, it can often be tough to force myself to stick this program, especially when I’m feeling great and just want to rip up the trail. But achieving the goals I’ve set for myself requires a long-term approach and a lot of discipline. If I want to stay in the game and continue to improve, I have to do so in a methodical, incremental way that my body can absorb. batman-base-meme


Trust me, I fully appreciate how hard it is to give up the “full throttle” style of training. In my 20s, I was a die-hard Crossfitter, doing 3 workouts a day. Even as I got older and mellowed out a bit, it was hard for me to admit that not needing my workouts collapsed in a pool of my sweat wasn’t the best path to adventure racing greatness. But letting yourself to get sucked in by the siren call of “more” is the start down the road to ruin.

As we’ve discussed, getting good at adventure racing is a multi-year effort, as it truly takes that long to accumulate the training effects necessary to make you a high-performance ultra endurance athlete. There are no shortcuts to the top, but there are plenty of false trails that will lead you back down to the bottom. You need to grind. You must stick to the plan.

There is a perpetual battle that must be waged by those of us who are active and training, and that is the battle of sticking with the plan. We are always bombarded by attacks on our attention, with “new” whiz-bang exercises and programs (cough… pot calling the kettle black…cough). The risk posed by this constant influx is that it distracts us from what really matters. Let’s face it, we humans are not particularly good at eliminating distractions or sticking with plans once we start, if we ever get around to actually starting…. With so many articles and advertisements urging us to “try these 10 exercises to burn more fat” or “this minor change to your workout with LITERALLY CHANGE YOUR LIFE!!!!”, it’s near impossible to stay the course. It’s made worse for adventure racers, because we LIKE shortcuts by nature, and always trying to do too much, to begin with (like being world-class at multiple sports).

I get it, I click on those advertisements too. But it’s always a letdown. Even if they actually have content of substantive value (and that’s a BIG if), I almost never implement them. Maybe I’ll do it once or twice, but then quickly forget them and revert to my old methods. It’s human instinct to choose what’s new and shining and for the purposes of becoming a good adventure racer, it’s not what we need to do. Even if it’s what we want to do.

Need vs. Want. It’s sometimes tough to tell the difference. I WANT to do the 10 exercises that will burn more fat. I NEED to be better at adventure racing to achieve my goal of a national championship. To do that I NEED to stick to the plan. Allow me to better illustrate with a recent conversation between me and my 3-year-old daughter Avery.

Avery: I need goldfish

Me: No, you want goldfish. You need to eat your broccoli

Avery: No, I need goldfish

Me: Why do you NEED goldfish?



Avery: Because I WANT it

We want to quickly gain fitness so we can be competitive, but also not have to spend much time gaining it. Hence the popularity of Crossfit Endurance and other programs that emphasize quick gains through training in power and intensity. And frankly, if your goal is to make it through an AR, then you could be well served by them. But for those of us who have an endurance season with multiple races, often close together, “hacking” your way to be fit enough to survive an AR isn’t going to cut it. Remember, we’re looking to COMPETE, not just complete. We know from studies of marathoners and Ironman triathletes that at least 95% of a race is conducted in the aerobic zone. AR is much the same. Training in the anaerobic zone is to train for 5% of your race. There’s merit there, for sure, which is discussed in length in the BAR-HIIT article, but this is about the 95%. You WANT to gain fitness by doing a few hill sprints or a Tabata squat session because it only takes a few minutes and you feel exhilarated afterward from the hormone rush. But you NEED to be an endurance athlete and that means spending time out on the trails.

safe to say that Mark Allen knows what the hell he’s talking about


Mark Allen, the greatest triathlete of all time (fact), says it plainly – smart endurance training is maximizing the accumulation of stress needed to exhibit improvement while minimizing extraneous damage. Sounds a lot like our principle for the Minimum Effective Dose, doesn’t it?

Or as world-famous strength coach Dan John puts it, “the plan is to keep the plan the plan”.

Okay, convinced now? Ready to talk details? Sweet.

Here’s how I’m getting better at base endurance in the coming year:

Phase 1 (Oct-Feb): Base


Phase 1 focuses on developing my aerobic capacity, slowly increasing the metabolic function of my body to maximize its ability to get faster and faster at the same maximum heart rate. Achieving this requires dedication and discipline as disruptions in the training schedule (namely, going above MAF threshold) will degrade my recovery. So every time I feel like I should “push it” just a little bit, because hey, why not, that moves me into the grey zone, wasting precious training time on exercise that is too much for my body to recover from within 24 hours but not enough to push me to a level that truly stresses the body to new levels.

I do this by spending 3-4 of my workouts during the week either running or biking below MAF threshold. Because of my commute to work, my workouts are limited to 1 hour, so either I run with my dogs on the roads near my house, or I bike in the early evenings if I leave work early (if my boss ever reads this, I’m joking). On Saturdays, I’m usually able to get in a 2-3 hour trail run or mountain bike, which allows me to train at an extended duration, testing nutrition plans, and tiring out my dogs. It can be a challenge to keep myself below my MAF threshold (trying to hike up a mountain tends to spike the heart rate…), but it’s crucial so that the long run doesn’t utter destroy me. On occasion, my long Saturday training will be replaced by a race, which obviously takes my heart rate well past MAF threshold, but hey, I’m not perfect, and I consider the races (trail runs, duathlons, biathlons, winter ARs) as great opportunities to measure my improvement.

Phase 2 (Mar-May): Build

Phase 2 focuses on sprinkling in some intense training sessions where I exceed MAF, sometimes going all the way up 90% of my max heart rate. These typically take the form of hill sprints, Tabata sprints on a treadmill, assault bike intervals, or intervals out on the trail. The important thing to remember in phase 2 is that the high-intensity workouts only occur sporadically (maybe 1 every 2 weeks or so) and otherwise I continue to incrementally improve my base endurance. I only substitute 1 base endurance workout for a high-intensity workout and only do so once I’ve proven (via repeated MAF tests) that my body is successfully adapting and improving its aerobic function. The higher intensity workouts are always followed by a rest day, but thankfully provide a wonderful break from the sometimes monotonous aerobic workouts that form the majority of my training time.

Phase 3 (Jun-Sep): Perform

Finally, Phase 3 occurs during the primary “adventure racing season”, between May and September. Because the adventure races (as well as the many other sports) come fast and furious, my otherwise disciplined training program is often disrupted by having to perform at race speed 2-4 times a month. This makes training less about trying to get better and more about ensuring that I’m ready to rock on race day. When a break does occur, I create microprograms, a 2-3 week training cycle focused on improving the metabolic zone that I’ve observed is weakest in past races (surprise! It’s going to be oxidative!). But I’m often going easy on my morning runs with the dogs and out on the trails only to work on technique instead of logging miles.


notice how base endurance is at the bottom of the pyramid, holding it all up? yeah…


Well, that about wraps up Base Endurance. Hopefully, I’m impressed upon you the reader the importance of

  1. Training a lot in the oxidative metabolic pathway
  2. Using the MAF method to ensure you are staying at a level of intensity that will cause slow and steady improvement and not harm your overall efforts
  3. Convinced you that sticking to the plan is the crucial

I’m sure there are plenty of follow-up questions, especially about when it’s okay to add a little top-end speed, but have no fear, those articles are still coming up!

Wait, hold up. Did you answer no to the “are you human?” question at the top of the article?