“You’re probably tired of me asking, but… am I doing enough to prepare for the (272-mile) Long Trail?”
And the next day…
“How do I improve my conditioning so that I have more energy after playing pickleball or going for a long walk in the morning and doing kettlebell training in the afternoon?”
Those two questions were posed to me last week by two different TNT members. And while the goals might seem rather different, I answered them the same way—with a whiteboard drawing inspired by a recent StrongFirst newsletter.
Here’s what I drew, and how it answers both questions.
The graph itself and the left set of lines (A, B, C) are from the newsletter.
Line A represents aerobic metabolism: as pace increases, physiological markers—like heart rate, respiration rate, and blood lactate—climb at a steady, manageable rate.
Line C is the lactic (or anaerobic) threshold: the point at which aerobic metabolism can no longer meet the body’s energy demands and the system shifts predominantly to anaerobic pathways.
Line B, representing anaerobic metabolism, is what follows: those same markers spike sharply alongside a smaller increase in pace.
As long as effort is kept below the anaerobic threshold, it can be maintained for hours and repeated day after day almost indefinitely. In contrast, paces above the threshold can only be maintained for minutes.
So the primary question for racers, martial artists, hikers, or pickleballers then becomes: “How do I move line C farther right so that I can move faster or exert more effort without ‘burning out’?”
There are two answers to that question. But research has shown that one method is superior—and it’s not the one that most people pick.
Why improving VO₂ max seems like the right method
VO₂ max is a measurement of the maximum rate at which our bodies can take in and utilize oxygen during intense exercise. It’s effectively the ceiling of our aerobic systems.
Moving that ceiling higher means more aerobic capacity—which sounds exactly like what we’d want to improve for enhancing endurance for a chosen event. And most people do opt for this strategy.
But it turns out that it’s only a marginally effective one.
To see what I mean, look back at the graph and notice how line A extends a little beyond the anaerobic threshold (line C). That’s what training VO₂ max does: it enables our bodies to utilize slightly more oxygen, which pushes the threshold slightly farther along the pace/effort axis by delaying the onset of predominantly anaerobic metabolism.
The main drawback of the method, though, is that it keeps us on the same line. Meaning: any given pace still requires the same amount of energy to maintain—we’ve simply increased how far along the line we can go.
That’s where my addition—the right set of lines (D, E, F)—comes into play.
Why improving strength, speed, or power works better
When we get stronger—I’ll use “stronger” as shorthand for strength, speed, or power improvements from here forward—our bodies expend less energy at any given amount of effort. So the same racing or hiking pace, pickleball game, series of punches, or session full of swings that used to demand a certain physiological output now costs less—because that effort represents a smaller percentage of our total capacity.
The result is that line A drops down to become line D. Aerobic demand at any given effort decreases across the board.
That’s why line F (the new anaerobic threshold) ends up so much farther to the right than line C—or even a “VO₂ max-enhanced” C₂ connected to the end of line A. The threshold hasn’t just been nudged—the entire aerobic line has shifted downward.
Line E (anaerobic metabolism, same as line B) still kicks in at the same absolute physiological ceiling, meaning that our VO₂ max hasn’t changed. But we now reach that ceiling at a significantly greater amount of effort (or faster pace) because the aerobic system demand shifted downward so dramatically.
And that connects to how I answered the two questions that started this tip.
How I answered each member’s question
In the case of the member training to hike the Long Trail, I explained that she is, in fact, doing just fine. She’s regularly rucking (hiking with a weighted pack) to prepare her legs for the trail, training for strength (with an endurance lean) at TNT a few days each week, and getting in some other fitness-oriented activities.
And given that she’s far stronger than she was the last time she did a (much longer) long trail a few years ago, her threshold and aerobic capacity are both in a meaningfully different place than they were then. (She completed that longer trail, but it was challenging—which is at least partly the cause of her current apprehension.)
Whether she’s also experienced a modest VO₂ max bump along the way is almost beside the point—the mechanism that matters most has been improving for a while now.
In the case of the pickleball-playing member, I emphasized that continuing to challenge herself with slightly heavier kettlebells—and making sure to follow-up the effort with intentional nutrition and recovery habits—would be the best use of her time, particularly because she’s already improving her endurance simply by playing pickleball.
Putting it into practice
For TNT members, this is less a call to change anything and more an invitation to understand that what you’re currently doing during group training is already working to move the threshold. (I always write programs with this stuff in mind, but the current program is particularly geared toward doing so.)
Of course, if you want to accelerate the adaptations, the levers are straightforward: progressive load (which means occasionally picking up a slightly heavier bell), consistent nutrition, and adequate recovery. None of those are dramatic changes on their own, but together they add up.
For anyone who’s not (yet) a TNT member—particularly if you’re an endurance athlete who hasn’t spent much time training your strength—consider adding a couple days of strength work to your training regimen. And if you’re still on the fence about training strength over VO₂ max, the research is there if you want to dig in: