The MicroCast

Got a question or a Hot or Not? Email ⁠[email protected]⁠.Want a coach who trains you as an individual, not an age group? Find 1:1 coaching and the Foothills community tier at microcosm-coaching.com.

Listener Joe is almost 38. He’s run on and off since he was 21, with long breaks, and he’s worried his potential is shrinking every year. His question: is his ceiling dropping faster than he can climb toward it? Zoë and TJ split the question in two: how far away is your ceiling, and how fast is it moving? For most amateur runners, the gap between where they are now and their potential is much bigger than anything age takes away. That’s especially true in the marathon and ultra.

They explain the physiology in plain terms. VO2 max levels off early and is mostly set by genetics. Threshold and running economy keep improving for years. Age mostly shrinks the engine, not how efficiently you use it. Before all that, TJ talks about coaching an athlete in person at Javelina Jundred and why the winner came from seven minutes back with 16 miles to go.

In this episode:

• Coaching at Javelina vs. crewing: using lap-by-lap data to adjust race strategy in real time
• Ego vs. effort: why starting conservatively prevents the late-race fade
• Training age vs. biological age, and why consistency matters more than birthdays
• Your engine (VO2 max), threshold, and running economy: which ones top out early and which keep improving
• How Paula Radcliffe’s economy improved about 15% while her VO2 max barely changed
• What age does take: max heart rate, fast-twitch muscle, power, and recovery
• Why a lot of what looks like aging is really training less consistently
• Why late starters can PR in their 40s and 50s
• Practical takeaways: string seasons together, build the foundation first, strength train, eat enough protein, and recover as hard as you train
• Why to be wary of fear-based marketing aimed at masters athletes

Every race costs something, and the bill usually comes in weeks, not days. Taper, race, recover, rebuild, and a “quick” 50K can quietly eat a month of training. In this episode, Zoë and TJ go through five rules for races that aren’t your main event: how to pick them, what to use them for, and how to race them without draining yourself before the race that matters most. Zoë also walks through her own 2027 season, and they answer a listener question about whether an online coach can really coach you without watching you run.

In this episode:

• Listener question: can a remote coach help if they never see you run? Why data and communication matter more than watching your form
• Why form is a weaker signal than you’d think, and when gait work belongs with a PT instead of a coach
• Zoë’s 2027 season: an off-season VO2 max block, Sean O’Brien 50K as a tune-up, Chianti as a B race, and Lavaredo and The Bear 100 as her A races
• Rule 1: Set intentions before you sign up. Is it a rehearsal, a fitness check, a hard training day, or just fun?
• Rule 2: Count the cost in weeks, not miles. Taper, muscle damage, refueling, and the hidden training you give up
• Rule 3: Adjust the taper and make recovery your top priority afterward
• Rule 4: Set process goals, not time goals, and don’t go to the well
• Rule 5: Treat it like a dress rehearsal: same fueling, gear, breakfast, and race plan
• A, B, and C races explained, and a simple exercise for planning your 2027 calendar
• Why your race plan should connect to a three-year vision, not just one season

Want help building a race season that actually supports your big goal? Book a free consultation at microcosm-coaching.com. Send your questions and Hot or Not topics to [email protected].

This is a replay of an episode about long runs while TJ is out of the office!

Want to train smarter, fuel better, and understand what your body actually needs? This episode unpacks the real science behind endurance training and fueling—no pseudoscience, no gimmicks.

Next, we tackle a listener question on calf cramps during long races, what causes them, how to respond in the moment, and how to prevent them through smarter training and fueling.

Finally, we close with a deep dive into metabolism for runners: ATP production, the limits of fat oxidation, how and why the “crossover point” matters, and why fasted or low-carb approaches can increase injury risk and reduce performance—especially for women.

⏱️ Timestamps00:00 – Intro & Boston 2026 webinar invite04:00 – Hot or Not: KT tape, dry needling, cupping, stretching vs. mobility22:00 – Listener Q: Calf cramps—on-course fixes and long-term prevention40:00 – Metabolism 101: fat vs. carb fueling, crossover point, LEA/RED-S risks

Subscribe for more evidence-based endurance coaching.Learn about 1:1 coaching at ⁠microcosm-coaching.com⁠ and follow ⁠@microcosmcoaching⁠ on Instagram.

Strides and VO2 max intervals both mean running fast, but they do completely different jobs. Strides are short and smooth, and they train the way you move. VO2 max intervals are long and brutal, and they train your heart. Mixing them up is one of the most common speed work mistakes we see as coaches.

In this episode, Zoë and TJ explain what each type of workout trains and how to structure both. They also cover the six mistakes that keep runners from getting the most out of their hard days. Before that, they answer a listener question on super shoes. A new 2026 study suggests that slower runners may benefit more than earlier research found.

In this episode:

• Meet Microcosm coach Kyle Jones, who specializes in masters athletes
• Zoë’s new science podcast with Nick Tiller, PhD: The Claims Department, launching October 15
• Listener question: when are you “fast enough” for super shoes?
• What the research says about super shoes at slower paces, including a 2026 ETH Zurich study of runners from 8:00 to 12:50 pace
• Nylon vs. carbon plates, lower-leg injury risk, and how to pick a pair
• Strides vs. VO2 max intervals: purpose, duration, and fatigue cost
• VO2 max, threshold, and running economy explained in plain language
• How to pace VO2 max intervals
• Why your watch’s VO2 max and threshold estimates aren’t reliable
• How to structure strides: length, recovery, effort, and where they go in your run
• 6 mistakes: running intervals too hard, stacking intensity, turning recovery into another interval, skipping strides, turning strides into a conditioning test, and chasing heart rate or pace numbers

Want a coach who knows the difference between 20 seconds and four minutes? Microcosm has roster spots open. Learn more at microcosm-coaching.com or email [email protected].

Coaching yourself? These are the five mistakes we see self-coached runners make most, and they're easier to fall into than you'd think. TJ and Zoë start with a listener question about the best time of day to train. Physiology gives late afternoon a small edge as core temperature and muscle readiness peak, but the real answer is whatever time lets you train consistently. They also cover running in the dark, why one missed workout doesn't matter, and whether evening runs wreck your sleep.

Then the list. First, copying the wrong model, including what the HERITAGE family study found when hundreds of people did the identical training program and got wildly different results. Second, the Franken-plan, where a podcast workout, a YouTube session, and a group track night get stitched together with nothing connecting them. Third, training your strengths instead of your limiters, and how to periodize hills, speed, and technical downhills months out from your goal race. Fourth, the planning fallacy, and the research on why we underestimate how long everything takes, even compared to our own worst-case guesses. Fifth, making big training decisions in the wrong emotional state, from post-DNF race sign-ups to the dangers of watching a Billy Yang film on a full stomach.

Plus, meet Microcosm coach Skylar, who works with road runners from the mile to the marathon.

Links
Foothills community ($10/month, coach calls + Slack community), code FOOTHILLS10: https://microcosm-coaching.com
Work with a Microcosm coach, including Coach Skylar: https://microcosm-coaching.com
Send us your questions and Hot or Nots: [email protected]

Lactic acid, static stretching, stability shoes, heel striking, 180 cadence, and icing everything: some running advice has not held up. Coaches Zoë Rom and TJ David cover six common myths, what the research actually shows, and why some of these ideas have stuck around for so long. Zoë also apologizes to everyone she sold motion-control shoes to in Northwest Arkansas.

Also in this episode:

• A listener asks why they feel wired and can't sleep after long runs. We cover what's going on in the nervous system, the caffeine you might be missing, and when this becomes a red flag.
• TJ gives an update on his health: he's been diagnosed with sarcoidosis after being misdiagnosed with HAPE at Leadville.
• Zoë recaps Mammoth Trailfest and shares a first look at next year's race plans.

Resources mentioned

• Cochrane Review (2022): running shoes for preventing lower limb injuries
• PEACE & LOVE framework for soft tissue injuries (Dubois & Esculier, BJSM)

Coaching: microcosm-coaching.com | Email: [email protected]
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Ready for your next ultra distance? Maybe. In this episode, we tackle the question of when to move up from the 50K to the 50 mile, 100K, 100 mile, and beyond, and why the "ladder" framing might be steering you wrong. Distance alone doesn't say much about what a race demands. A mountainous 50K can ask more of you than a runnable 50 miler, so we talk about how to size up a race by duration, terrain, and your own capacity.

We start with a listener question: should you practice run-walking during ultra training, especially on tired legs in high-volume weeks? We explain why power hiking is a race skill, why fixed run-walk ratios work well in training but poorly in races, and why extra walking can be stress without much stimulus.

From there, we cover how to identify your real weaknesses. That means separating a bad day from a pattern, finding root causes instead of symptoms, and deciding which limiters to address first. Spoiler: it's often fueling and hydration. We share practical approaches for improving speed, climbing, descending, durability, and your gut. We finish with the signs you're ready to move up, what does and doesn't change in training as races get longer, the special demands of 200 milers, and when it's better to wait.

Plus, meet Microcosm coach Kylee Van Horn: nearly 20 years of coaching across road, track, and trail, a registered dietitian's lens on fueling, and a hot take about why you can't cross-train your way to a 100 miler.

In this episode:

• Kylee Van Horn coach spotlight
• Listener question: should you practice run-walking?
• Power hiking vs. walking, and why fixed ratios fail on race day
• "Stress, not stimulus": the hidden cost of extra walking volume
• Why the ultra distance "ladder" is a myth
• How to find your weaknesses and root causes
• Prioritizing limiters: low-hanging fruit first
• Training for speed, climbing, descending, durability, and GI tolerance
• Signs you're ready to move up in distance
• Why 50K and 100 mile training look more similar than you think
• What makes 200 milers different
• When not to move up, and the six-year test

Want to work with Kylee or another Microcosm coach? We have roster spots available. Email [email protected] or visit microcosm-coaching.com.

If you liked this episode, subscribe, follow, and leave us a review. We read all four of them.

Zoë's article on Ability vs. Ambition

YDS Episode on "Racing Weight"

There's always a gap between where you are as an athlete and where you want to be. Zoë wrote about it for UltraSignup , "Closing the Gap Between Ability and Ambition", and this week TJ reads it back to her, days before she lines up at Run Rabbit Run 100 for the third time. They dig into Ira Glass's idea of "the gap," why admitting you want to be great feels so vulnerable, what "spiritual durability" actually means in a training context, and why the most successful athletes usually aren't the most talented — they're the ones willing to sit in that discomfort long enough to close it.

From there: why repeat a race you've already done well twice, why you technically can't (same course, different athlete, different river), how Zoë structures a year around two big hundreds using a rule of thirds, and how she's managing the comparison trap and her mental diet heading into a deeper field than she's ever raced.

Then a listener question that comes up constantly: "I'm training more than ever and I've gained weight instead of losing it. Is that normal?" Yes — and here's what the scale is actually measuring: glycogen and the water it binds, inflammation from tissue repair, blood volume, food in transit. Plus what the research really says about body weight and injury risk, and when weight change is worth a conversation with a doctor.

How many miles a week do you need to run to get better? It's the question coaches hear most, and the annoying answer is: enough to create an adaptation, not so much that you can't absorb it. The body doesn't experience a mileage total. A mile on a 14er and a mile on a track are completely different stresses, which is why time at effort is a better way to think about volume than distance.

TJ and Zoë break volume into four levers. How much: the difference between the minimum effective dose, the optimal dose, and the maximum recoverable dose, and why most runners should be asking about the middle one. How often: what 3, 4, 5, 6, and 7 days a week actually get you, and why frequency is the most overlooked tool for newer runners. How long: why 15 + 5 is not a 20-mile long run, and why the cost of a run doesn't rise in a straight line. And where: easy/hard distribution, the weekend-warrior trap, and why back-to-back long runs are a tool rather than an organizing principle. It all starts from the same place — the week you can actually repeat, found in your TrainingPeaks history, not the week you're proudest of.

First, TJ has an answer for what happened at Leadville. Then: a listener question about Nordic skiing all winter and protecting running fitness for a spring 50K, and Hot or Not on mocktails, aid station hydration mixes, and Tiger Balm.

Questions for a future episode: [email protected]

Coaching and community: https://microcosm-coaching.com

Leadville 100 week gave Microcosm both ends of the sport in a single day: coach TJ David's athlete McKendree Hickory won the women's race in her 100-mile debut, and TJ himself dropped at the Winfield turnaround after nearly fifty miles of not being able to breathe.

Zoë and TJ take both apart honestly. On the win: what five months of coaching actually changed, why TJ inferred McKendree was naturally durable from four years of training history, and how identifying two points of friction — pacing discipline and a reluctance to lean into discomfort late in races — mattered more than overhauling everything. She raced her dress rehearsals under fatigue, ran a conservative early pace by design, and degraded only 8.25 percent over a hundred miles at altitude, where ten to fifteen is considered excellent.

On the DNF: the difference between confidence and self-efficacy, why protecting mental bandwidth during race week is a training variable, and what it's like when a heart rate that should read 114 reads 140 at mile ten. TJ walks through the internal argument, the broken poles on Hope Pass, the decision at Winfield, and how he's processing a race he trained two years for.

Plus a listener question up front: can you build a Boston qualifier on a treadmill, and what has to happen outside anyway.

Questions for a future episode: [email protected]

Coaching and community: https://microcosm-coaching.com