When athletes talk about improving next season, the conversation often turns to getting stronger, raising threshold, or producing more power. Those can all be worthwhile goals, but before deciding how to pursue them, we need to consider what the athlete is preparing for. An improvement in a training metric is useful only to the extent that it supports the demands of the race.
For an Ironman athlete, those demands extend well beyond producing higher watts on a test. We need the ability to sustain appropriate output for hours, manage the energy cost of that output, absorb nutrition, and arrive at the marathon prepared to run. An athlete can improve short-duration power without significantly improving any of those things. The training has produced an adaptation, but whether it is the adaptation we need is another question.
A recent Triathlon Magazine article about Sam Long’s Kona preparation brought this into focus. Working with Parker Spencer, Long addressed his VLaMax, carbohydrate use, and race execution in preparation for the specific demands of Ironman. What interested me most was the decision behind that work: an athlete who was already exceptionally fit was identifying which physiological changes would make him better at the distance he wanted to race.
That is where I start when considering an athlete’s preparation. What is the end goal, what does that event require, and which adaptations will help us meet those demands?
Where VLaMax Came From
Although VLaMax has become more visible in endurance sport, its origins go back several decades. In the early 1970s, physician Alois Mader was the leading sports doctor at SC Chemie Halle in East Germany, the home club of swimmer Kornelia Ender. Working with chemist Peter Haase, he developed a method for measuring lactate from just 20 microliters of blood collected from the earlobe. Mader later described using those samples in 1973 to predict some of Ender’s future performances. She went on to win four Olympic gold medals in Montreal in 1976.
Mader’s interest extended beyond identifying an athlete’s threshold to understanding what determined it. In 1984, he developed a mathematical model of human energy metabolism that included the maximal rate of lactate production in working muscle, the property now described as VLaMax. The model considered threshold in relation to both glycolytic lactate production and the aerobic system’s ability to use and clear lactate. This helped explain why athletes with similar VO₂max values could have different thresholds.
Since muscle lactate production cannot be measured directly through a routine test in a living athlete, Mader proposed a practical estimate in 1994. Athletes performed a short, maximal sprint, with blood lactate measured before and afterward to calculate its rate of accumulation. That approach has been refined and debated over the following decades. More recently, metabolic profiling software has brought the concept into wider use in professional cycling and triathlon; Mader himself served on the advisory board of one of those companies.
What VLaMax Tells Us, and What It Does Not
VLaMax describes maximal glycolytic lactate production rate. In practical terms, it helps us consider an athlete’s capacity to produce energy rapidly through the breakdown of carbohydrate. That capacity supports short, powerful efforts, but it also has implications for how the athlete produces energy at sustained intensities.
The aerobic and glycolytic systems work together. Aerobic metabolism uses oxygen to produce energy from fat and carbohydrate, while glycolysis can supply energy rapidly without directly requiring oxygen. VO₂max describes the upper limit of oxygen uptake; VLaMax describes a different aspect of the athlete’s metabolic capacity. Knowing one does not give us a complete understanding of the other, or of the athlete’s ability to sustain Ironman output.
It is also important to understand what a VLaMax test measures. A common protocol uses a 10- to 15-second maximal sprint and blood sampling to estimate the rate of lactate accumulation. Blood lactate reflects production, movement between tissues, and clearance, so the result is an estimate of the underlying muscle property rather than a direct measurement of it.
The protocol and the athlete’s preparation matter. Sprint duration, warm-up, starting lactate, and sampling times can all influence the result. One cycling study found variation approaching 19 percent between repeated tests in the same athletes, which means a small change may reflect testing variability rather than a meaningful adaptation. Consistency in testing conditions is essential if we want to use the information to guide training.
None of this makes lactate something we need to eliminate. The heart, slow-twitch muscle fibers, and other tissues use it as fuel. The relevant question is how the athlete’s metabolic systems interact and whether that profile supports the event.
Why VLaMax Matters for Ironman
Within Mader’s model, a higher VLaMax is associated with greater carbohydrate use at a given power and a lower threshold when other factors remain equal. A lower VLaMax can favor sustained output with a lower carbohydrate cost, while a higher VLaMax supports the ability to produce power quickly. The value of either profile depends on what we are asking the athlete to do.
Short-course racing can require repeated accelerations, responses to other athletes, and high power after abrupt changes in pace. Ironman requires an athlete to sustain work over eight, twelve, or sixteen hours while managing a finite capacity to store, consume, and absorb fuel. Both athletes benefit from strong aerobic development, but the balance of abilities they need is different.
Research gives us reason to examine that balance. In a study of 182 cyclists and triathletes, higher sprint-test lactate rates were associated with lower power at both lactate thresholds, even after accounting for aerobic capacity and efficiency. As an observational study, it cannot establish that lowering VLaMax will cause threshold to improve. It does support looking beyond VO₂max when trying to understand an athlete’s endurance profile.
For an Ironman athlete, the potential benefit is practical. If the carbohydrate cost of producing race power decreases while aerobic capacity is maintained, that output becomes less metabolically demanding. This may help preserve fuel availability, reduce the pressure to consume carbohydrate at a rate the gut struggles to tolerate, and support the run that follows.
That possibility does not justify automatically increasing race power or reducing carbohydrate intake. Those decisions still need to be supported by the athlete’s responses in training. A metabolic profile can help explain what we see, but it does not replace the work of establishing sustainable pacing and effective fueling.
Consider the athlete whose short-duration cycling power continues to improve while their ability to hold steady power late in a long ride remains unchanged. More hard intervals may improve an ability they already possess without addressing what limits their race. They may need greater aerobic endurance, fatigue resistance, better fueling, or more time becoming comfortable and effective in the aero position. The most useful improvement for that athlete may show up four or five hours into a ride rather than in a fresh power test.
What Long’s Kona Preparation Illustrates
Spencer began working with Long as a metabolic testing consultant approximately two months before Kona. Using a portable metabolic analyzer, blood lactate testing, and INSCYD profiling software, he assessed Long’s physiology and found that, despite Long’s reputation on the bike, his running profile was stronger. Their work also addressed the cost of the substantial surges Long had been using to pass other athletes.
In Kona, Long took a more controlled approach, with much of his passing occurring in the final 30 miles of the bike. He produced his highest Ironman race power and followed it with a 2:42:57 marathon, finishing sixth in his debut. Over approximately six weeks of preparation, his estimated VLaMax decreased by 43 percent, power at FatMax increased by 16 percent, and estimated maximal lactate steady-state power increased by nearly 10 percent. His VO₂max changed very little.
Those reported changes illustrate how performance can improve through changes in the way an athlete sustains and fuels output, even when maximal aerobic capacity remains relatively stable. They also need to be understood in context: this was a highly trained professional, supported by frequent testing and able to commit fully to the preparation.
Specific Preparation Involves Trade-Offs
The glycolytic capacity that contributes to carbohydrate demand also supports sprinting, surging, closing gaps, and producing high power over short periods. As preparation becomes more focused on sustained endurance, some of those shorter efforts may become less impressive. Sprint performance, one-minute power, five-minute power, or short running efforts may plateau or decline while the athlete becomes better prepared for a long race.
Spencer described the reduction in Long’s VLaMax as an example of the different demands of 70.3 and Ironman racing, and why performing well at both can be challenging. A 70.3 is raced closer to threshold and can place greater value on higher-intensity output. Ironman places a greater emphasis on sustaining work economically over a much longer day. Long’s decision to skip the 70.3 World Championship in Nice reflected his commitment to Kona preparation.
For age-group athletes, the same consideration belongs in season planning. We need to decide which event takes priority and allow the training to move toward its demands. Preparing to be at our best for a fast 70.3 while also trying to optimize Ironman performance within the same block can involve competing priorities. That does not make either goal inappropriate, but it does require us to understand what we are asking of the athlete.
Adaptation Requires Time and Continued Attention
Long’s changes occurred quickly enough that Spencer expressed surprise at their magnitude. That should not become an expectation for an age-group athlete balancing training with work, family, and limited recovery. Some metabolic markers can change within a training block, while deeper aerobic development, including changes in mitochondrial and capillary capacity, accumulates over months and years.
The adaptations also depend on the training we continue to do. Returning to frequent surges, hard group rides, and repeated high-intensity efforts changes the stimulus again. A focused block needs enough time to produce a response, and its value should be assessed through the athlete’s ability to perform the work required by the event, alongside any testing we use.
How This Has Changed My Coaching
Considering VLaMax has been one of the more significant changes in my coaching approach over the past two years. Improving aerobic capacity, threshold, strength, and speed remains valuable, but I now consider those qualities more specifically in relation to the athlete’s event. How long will they be working? At what intensity? What will the fuel demands be, and where has their performance tended to break down?
Starting with those questions has helped me prepare athletes with greater precision and has improved our results. General fitness still matters, but we need to understand how an improvement will carry over to the race. A higher number on a test means more when we can explain how it supports the athlete’s ability to execute that event.
This perspective also helps explain why athletes can struggle when moving between distances. After spending months preparing to sustain economical output for an Ironman, an athlete may find the demands of a fast 70.3 or Olympic-distance race less familiar. Their body has adapted to the work we have emphasized. Expecting every performance quality to remain equally developed overlooks the specificity of that preparation.
As athletes prepare with increasing specificity, there is less room to assume that being generally fit will allow us to perform equally well across every distance. If the goal is a strong Ironman, the training needs to reflect what a strong Ironman requires.
Accepting the Cost of the Adaptation
Athletes often want the benefits of specific preparation while remaining reluctant to accept its trade-offs. An athlete preparing for a 50K may develop greater economy, fat utilization, and durability while finding short, hard efforts more difficult. If that preparation reduces glycolytic capacity, a decline in short-duration power can be consistent with the direction of the training.
We still need to assess changes thoughtfully rather than dismissing every decline as expected. But we also need to evaluate fitness in relation to the goal. We cannot maximize every quality simultaneously, particularly with limited time and recovery. Part of preparing well is identifying which abilities matter most and accepting that others may receive less attention during that period.
Where VO₂max Work Fits
Ironman preparation can include high-intensity training. A higher aerobic ceiling can support endurance performance, and shorter, intense intervals have a place at appropriate points in the season. The question is how that work fits within the larger preparation and what it costs the athlete.
If a training approach improves VO₂max while also increasing glycolytic capacity, we need to consider the overall effect on the athlete’s endurance goal. We also need to consider whether the work and its recovery demands are limiting the aerobic development at and below the first lactate threshold, or LT1, that supports prolonged output and substantial fat oxidation.
This is where the athlete’s profile matters. A better five-minute power number may represent useful progress for one athlete and do little to address another athlete’s Ironman limiter. I want to understand whether the work is improving the qualities we need without taking too much away from the training that supports them.
Why Many Age-Group Athletes May Benefit From a Lower VLaMax
My view is that many age-group athletes preparing for Ironman would benefit from reducing VLaMax, particularly when their training has consistently emphasized intensity. Busy athletes understandably gravitate toward shorter sessions that feel productive, “time crunched training”. Group rides, hard finishes, and demanding intervals provide immediate evidence of effort, while controlled aerobic training can feel insufficient by comparison.
Over time, that pattern repeatedly develops the ability to produce harder efforts, sometimes at the expense of the sustained aerobic work the athlete needs. The training that supports Ironman performance is often less immediately satisfying: longer, controlled sessions that can be repeated consistently and absorbed without compromising the rest of the week.
An athlete’s willingness to do that work matters. We need enough consistency and patience to evaluate its effect on sustained output, even when the session itself does not produce a new personal best or leave the athlete feeling exhausted.
Applying This to Training
There is no established workout that reliably lowers VLaMax in every experienced triathlete. Research offers useful observations, and coaches have practical approaches, but the evidence does not support treating any single session as a guaranteed intervention. The starting point remains the athlete’s profile, training history, available recovery, and race limitations.
1. Develop Aerobic Volume You Can Consistently Absorb
A review of the research found that greater low-intensity training volume tended to reduce VLaMax, although the number of studies was limited and individual responses varied. For an athlete, applying that information may mean improving the consistency of easy training, gradually extending rides, or adding an endurance session they can recover from.
It may also mean reducing the intensity of existing sessions so that more useful work fits within the week. A controlled two-hour ride might progress to two and a half hours before additional duration is considered. If easy days routinely become moderate days, adjusting that pattern may be more productive than immediately adding more training. We need to understand whether the current workload is producing the intended adaptation before increasing it.
2. Build Sustained Output Through Controlled Intervals
Longer efforts below threshold can help accumulate sustained work and practice the execution required on race day. Depending on the athlete’s preparation, examples might include three 15-minute or two 25-minute blocks below the second lactate threshold, with easy riding between efforts. The appropriate intensity should be set for the athlete rather than assumed from formulas – an athlete’s true threshold and “FTP” can look very different.
These sessions are coaching tools rather than proven VLaMax-lowering protocols. They allow us to observe breathing, perceived effort, heart rate, fueling, and the ability to remain in position. Progression can come from spending more time at a controlled output before increasing power. An athlete who fades substantially is providing information about the sustainability of the effort; forcing a higher number in the final interval does not resolve that limitation.
A small six-month study of experienced athletes preparing for a Race Across America relay found a reduction in VLaMax alongside an increase in critical power. Their preparation included substantial low- and moderate-intensity training. The findings suggest that the profile can change, but they do not identify which component of the training produced the change.
3. Account for All of Your High-Intensity Work
The training plan does not always capture the full amount of intensity an athlete completes. Accelerating over hills, responding to a group ride, pushing the finish, and adding unplanned surges all contribute to the workload. Each effort needs to be considered within the week, particularly when it increases recovery demands or reduces the quality and consistency of aerobic training.
The relationship between sprint training and VLaMax is also more complex than assuming that every hard effort raises it. One six-week study found that four to six 30-second maximal sprints, performed three times per week, reduced measured VLaMax. The participants were recreationally active men rather than trained cyclists, so the findings are not a prescription for Ironman preparation. They do demonstrate why we need to be careful about drawing universal conclusions from a training label or one protocol. Individuals vary.
I want intensity to address an identifiable need. If its main effect is making the week more difficult while interfering with the work most relevant to the race, we need to reconsider its place.
4. Give Low-Cadence Work a Specific Purpose
Some coaches use sustained, moderately hard, big-gear riding with the intention of lowering VLaMax, but direct evidence for that effect remains limited. At a given power, reducing cadence increases the force required per pedal stroke. That mechanical change does not, on its own, establish that the session will produce the metabolic adaptation we want. One study in highly trained veteran cyclists found no performance advantage from low-cadence intervals.
5. Keep Strength Training in Context
Some strength interventions have increased VLaMax in studies (specifically, circuit-style training), but that does not establish that strength training is detrimental to Ironman performance. Its value depends on the program, timing, dose, and athlete. We need to decide when to develop strength and when to maintain it with a smaller workload that fits alongside endurance preparation.
If a heavy lower-body session repeatedly compromises key endurance sessions, the program needs adjustment. Strength training should be evaluated by its contribution to the athlete’s overall preparation, including the recovery it requires.
Fueling and Recovery Support the Adaptation
A metabolic metric can create the temptation to manipulate the conditions that influence it. With VLaMax, carbohydrate availability is an obvious example. A pilot study found that lower carbohydrate intake combined with glycogen-depleting exercise before testing reduced measured VLaMax. That does not establish an improvement in endurance physiology; lower glycogen availability can reduce lactate production during the sprint test itself.
Restricting carbohydrate simply to obtain a lower result undermines the usefulness of the assessment. We need to fuel the training being prescribed, practice race nutrition, and arrive at repeat tests under comparable conditions. Even when carbohydrate cost at race intensity decreases, race-day fueling remains necessary. Changes in intake should be guided by the athlete’s demonstrated needs and tolerance.
Sleep and recovery belong in this discussion because they support the ability to absorb training consistently. They are not established methods for directly lowering VLaMax, but inadequate recovery limits the work an athlete can sustain. Meals, sleep, and the arrangement of demanding sessions need to support the training rather than leave the athlete repeatedly carrying fatigue into the next week.
Evaluating Whether the Preparation Is Working
The most useful assessment remains the athlete’s ability to meet the demands of the race. Can they sustain appropriate power later in a long ride? Can they remain in position and tolerate their fueling plan? Can they begin the run with the effort under control? Those outcomes give a metabolic test its practical context.
Repeat testing can help explain changes when the protocol and preparation are consistent, but a lower VLaMax is not the only route to better endurance performance. One athlete may improve through aerobic development without a meaningful change in VLaMax. Another may benefit from reducing glycolytic contribution. A third may need better pacing and fueling before their existing fitness can translate into a better race.
Our job is to identify what the athlete needs and direct the available time and recovery toward it. That requires looking beyond the metrics that are easiest to celebrate and considering whether the preparation is improving the athlete’s ability to perform for the specific event and across the entire event.
For many Ironman athletes, becoming better prepared may involve accepting less impressive short-duration efforts in exchange for output they can sustain later in the day. If the goal is to ride well and still be able to run, we need to give that adaptation the time and attention it requires. Ironman is a game of patience – in training and on race day.
The temptation for coaches and athletes is to always chase a bigger engine. VLaMax asks us to think about how we build it, and to make sure our training targets the metabolic demands of race day.
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About Elizabeth Waterstraat
Elizabeth Waterstraat is the founder and head coach of Multisport Mastery, established in 2007. A USA Triathlon Level III Coach with 20 years of coaching experience and 26 years as an endurance athlete, Elizabeth works with athletes ranging from first-time triathletes to national champions and world championship qualifiers. Her coaching approach emphasizes individualized training, athlete education, consistency, and long-term development.
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