How to Change Your VLaMax (And What Actually Moves the Needle)
- Taj Krieger
- Mar 8
- 7 min read
Most coaches treat VLaMax like a fixed trait — something you test, note down, and then work around. That's wrong, and it's costing athletes months of misdirected training.
VLaMax is trainable. It responds to stimulus the same way VO2max and LT1 do. If your number is too high and it's suppressing fat oxidation, pushing your heart rate up in Zone 2, and capping your threshold power, you can lower it. If it's too low and you're getting dropped every time the race accelerates, you can raise it. But the training that moves it in each direction is not just "different." It's the opposite. Doing the wrong type will actively move you further from your goal.
Here's what the INSCYD research says actually works, the mechanism behind it, and how to know which direction you need to go.
The Number You Should Know Before You Read This
Research using INSCYD data found that VO2max explains roughly 20% of the performance gap between amateur and professional cyclists. VLaMax accounts for 75%.
That's not a knock on VO2max — it matters. But it means that if you've been optimizing your training around your aerobic capacity while your VLaMax sits at the wrong value for your event, you're ignoring the bigger lever. Most athletes have never had their VLaMax measured.
Why "Just Do More Zone 2" Doesn't Work on Its Own
When athletes find out their VLaMax is high, the instinct is to pile on easy mileage. The problem is that "easy" is doing a lot of work in that sentence — and the definition of easy matters precisely.
Zone 2 calculated from 55–65% of FTP is not the same as Zone 2 set from your actual LT1. For an athlete with a VLaMax of 0.7 mmol/L/s, their LT1 might sit at 58% of FTP — meaning any work at "Zone 2" per the standard formula is already above their aerobic threshold, stimulating glycolysis rather than suppressing it. You think you're building aerobic base. Physiologically, you're doing the opposite.
There's a second problem even if you have your LT1 correctly identified: training that is too easy doesn't recruit the fast-twitch muscle fibers that need to de-adapt. Lowering VLaMax means reducing the glycolytic enzyme activity in your type II fibers. Those fibers have a higher recruitment threshold — they don't respond to work that never taxes them.
The actual lowering stimulus requires a specific intensity window. And it's not pure Zone 2
What VLaMax Actually Responds To
VLaMax is a measure of your maximal glycolytic rate — how fast your muscles can produce lactate through anaerobic metabolism. It's determined by your glycolytic enzyme activity, primarily phosphofructokinase (PFK), concentrated in fast-twitch muscle fibers. Your training history has set this number. Changing it means giving those fibers a new, consistent stimulus over several months.
Two primary levers control it:
High-intensity work raises VLaMax. Maximal or near-maximal efforts recruit type II fibers and upregulate the glycolytic enzymes that drive lactate production. Even short efforts — the INSCYD research indicates as little as 5 seconds of high-intensity work activates glycolysis enough to send an adaptation signal. The more you train this system, the more capable it becomes.
The right intensity with the right structure lowers VLaMax. Not pure Zone 1 — mid-range work above base endurance, below anaerobic threshold, combined with specific structural elements. The intensity needs to be high enough to recruit the targeted fast-twitch fibers, but not high enough to upregulate glycolytic capacity. This is a narrower window than most athletes expect.
The implication: every training block is either raising or lowering your VLaMax. Whether that's intentional is a different question.
Protocol 1: Lowering VLaMax (Road Racing, Gran Fondo, Sustained Power Events)
Who this applies to: Cyclists with VLaMax above 0.5 mmol/L/s whose performance ceiling is fat oxidation, Zone 2 economy, and threshold power. Common profile: serious road racer or gran fondo rider who does everything "right" and still plateaus.
Timeline: 10–16 weeks minimum. First measurable changes typically appear at 6–8 weeks. Full VLaMax reduction potential takes several months of consistent execution — there's no shortcut.
The core stimulus: Mid-range intensity — above your aerobic base, below your anaerobic threshold — paired with low cadence to force higher torque and recruit the fast-twitch fibers you're targeting. This is not the long, easy ride; it's a structured effort in the moderate intensity zone that requires discipline to stay in.
The protocol:
Intensity anchor: Sessions should sit between LT1 and LT2 — not below LT1, and not at threshold. Specifically: combine this intensity with reduced cadence (55–70 rpm) to increase mechanical load and fiber recruitment without spiking glycolytic rate. A practical session format: 4 × 20 minutes at target intensity and low cadence, with full recovery between blocks. Repeat this structure multiple times per week within longer rides.
Avoid all surges: Even 5 seconds of high-intensity effort provides enough glycolytic activation to partially cancel the adaptation signal. In the lowering phase, no sprint out of corners, no punchy climbs, no accelerations. This is the rule most athletes break without realizing it.
Glycogen management: Train key sessions without fully replenishing glycogen beforehand. Not depleted — that impairs performance and adaptation. But not fully topped up either. Starting a mid-intensity session with lowered glycogen stores reduces glycolytic fuel availability, accelerates fat pathway reliance, and amplifies the VLaMax de-adaptation signal.
Training frequency: This adaptation requires a recurring stimulus. Minimum 5–6 sessions per week — not because volume alone drives adaptation, but because VLaMax reduction specifically does not respond to a "weekend warrior" pattern. The signal needs to be repeated.
Weekly structure example:
Monday: Off or easy spin 45 min
Tuesday: 3 hr ride — 4 × 20 min mid-intensity, low cadence (60 rpm), moderate carb intake
Wednesday: 60 min easy + optional strength
Thursday: 3–4 hr ride — 4 × 20 min mid-intensity blocks, low cadence, lower carb pre-ride
Friday: Off
Saturday: 4–5 hr endurance ride — mid-intensity blocks embedded throughout
Sunday: 2–3 hr easy
What to track: Power output and heart rate at a fixed moderate intensity. As VLaMax drops and fat oxidation improves, you'll either hold the same power at a lower heart rate or produce more power at the same heart rate. This is the real-time signal that the adaptation is working.
Retest at 10–12 weeks with INSCYD. A reduction of 0.05–0.15 mmol/L/s is realistic in this window with consistent execution.
Protocol 2: Raising VLaMax (Criterium, Track, Repeated Maximal Surges)
Who this applies to: Cyclists with VLaMax below 0.3 mmol/L/s who need to be competitive in races decided by repeated short accelerations. A low-VLaMax athlete has exceptional aerobic economy — they can ride endurance all day — but gets gapped every time the race accelerates.
Timeline: 6–10 weeks. VLaMax responds faster to high-intensity stimulus than it does to aerobic base work. The glycolytic enzymes upregulate relatively quickly under the right signal.
The core stimulus: Maximum glycolytic activation, repeated multiple times per week, with sufficient recovery between efforts for the system to fully reset — meaning pH normalizes — before the next effort begins.
The protocol:
Gym training: One of the most effective and underused tools for raising VLaMax. The mechanism is direct: resistance exercise targeting major cycling muscles at 12–30 seconds per set, continuous repetitions (no rest within a set), medium-to-high load, stopping before failure. Going to failure drops muscle pH too far and actually reduces the glycolytic training effect. Keep the sets to the 12–30 second window — shorter sets undershoot, longer sets can't sustain peak glycolytic activation.
Sprint and interval training: 10–30 second efforts at just below maximum power, with full recovery between efforts (3–5 min minimum — enough for blood lactate and pH to normalize). The criterion is not time — it's that the next effort must be as powerful as the first. If power degrades across sets, recovery was insufficient. 2–3 sessions per week is the target.
Everything else: easy only. Any training outside the maximal glycolytic sessions must be genuinely low intensity. Mid-range efforts — tempo, sweetspot, threshold — are known to de-adapt VLaMax. They send the opposite signal. During a VLaMax raising block, there is no middle ground: sessions are either maximal glycolytic work or easy aerobic maintenance.
Stay fully carb-fueled: Low-carb or high-fat nutrition decreases glycolytic enzyme activity in the muscle. For a VLaMax raising block, glycogen stores should be fully topped up before every session. The adaptation depends on the glycolytic system being maximally available during training.
Volume: Reduce total endurance volume 20–30% during this phase. Competing adaptations cancel each other out. More aerobic base volume alongside this protocol reduces the glycolytic signal.
Weekly structure example:
Monday: Off or easy spin 45 min
Tuesday: Gym — 3 × [4 × 20s leg press/squats, continuous reps, not to failure]
Wednesday: Easy aerobic 60 min
Thursday: Sprint intervals — 8 × 20s near-max, 4 min full rest between
Friday: Off
Saturday: Race simulation or criterium — repeated maximal surges
Sunday: Easy aerobic 60–90 min
Retest at 8 weeks. An increase of 0.1–0.2 mmol/L/s is achievable with genuinely maximal sessions and consistent frequency.
What INSCYD Adds to This Process
Both protocols can be approximated from first principles. What INSCYD adds is precision — and the ability to confirm the adaptation actually occurred.
Without testing, you're estimating your LT1 (the critical anchor for Protocol 1), working from a guessed VLaMax baseline, and assuming the protocol worked without confirmation. A 12-week block executed at the wrong intensity produces no meaningful change. You won't find out until the race.
With an INSCYD test before the block, you get your exact LT1 to anchor intensity correctly, your actual VLaMax as the baseline, your FatMax and CarbMax for race-day planning, and a reference point to retest against. At 10–12 weeks, a second test tells you exactly what moved, what didn't, and what to adjust before your target event.
Most athletes run one training block and hope for the best. Testing before and after removes the guesswork from every block you build from this point forward.
The Takeaway
VLaMax is not a fixed trait. It's a training variable — one that most coaches either ignore or treat as something that can't be changed. If your number is too high, a targeted mid-intensity block with the right structural elements and glycogen management will lower it over 10–16 weeks. If it's too low, maximal short efforts in the gym and on the bike will raise it in 6–10 weeks.
The protocol that works depends on which direction you need to go. And the only way to know that with certainty is to measure it.
If you want to know your actual VLaMax rather than estimating it, the INSCYD Test gives you the full metabolic picture — VLaMax, VO2max, LT1, FatMax, and CarbMax — in a single 90-minute session.
Download the FREE protocol here!
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