The number that came back to haunt cycling
There is an invisible frontier in the history of the Tour de France's great climbs. For years it worked as a dividing line between the possible and the suspicious: about 6.10 W/kg of estimated power, sustained for 30 to 40 minutes of climbing. Before 2013, practically every ascent above this level belonged to a cyclist later confirmed as doped, in the era of EPO and blood manipulation. Then came a decade of silence, in which nobody came close. Now, between 2024 and 2025, four climbs by Tadej Pogacar and two by Jonas Vingegaard have crossed that line again.
The gap between the proven doping era and the presumably clean era, once about 14%, shrank to something near 6%. It is this shrinkage that reignites, every July, the same question: are these numbers humanly possible without doping?
Where this threshold comes from
The watts yardstick was born with French coach Antoine Vayer and engineer Frederic Portoleau. They popularized the idea of estimating a climb's power from the time, the elevation gain and the weight, normalizing everything for a standard 78 kg cyclist. On this scale, Vayer set provocative bands: above 410 standard watts the performance would be "suspicious", above 430 watts "miraculous" and above 450 watts "mutant". The logic is to treat power as an indirect indicator of doping, without depending on a blood test.
The weak point of this approach is exactly what it promises. The models used by Vayer and Portoleau require data that is almost never truly measured: frontal body area, air density, rolling resistance, mechanical efficiency and exact weight on the day. None of these values comes from a public power meter. They are inferred. That is why every number circulating in the debate carries a margin of error that rarely makes the headlines.
What clean physiology already delivers
Before shouting "impossible", it is worth remembering where the real biological frontier lies. Genuine elite cyclists have VO2max far above average: the men's peloton ceiling usually sits between 70 and 85 ml/kg/min. Pogacar reportedly recorded 89.4 in the laboratory, and there are reports of even higher values in other athletes. Vingegaard reportedly marked about 97 ml/kg/min as a junior, and Greg LeMond is historically cited at around 92.5 at his peak, although that number is disputed. Sustaining 5 to 6 W/kg cleanly is not science fiction for those with that engine.
Beyond the engine, a decade of legal gains has piled up. The so-called carbohydrate revolution took World Tour athletes from about 60 grams per hour to 100 to 120 grams per hour of intake during stages, something the literature associates with improved performance in long races. Add to that more aerodynamic bikes, wind tunnels, real-time power meters, weather forecasting and finer periodization. Estimates from within the sport itself speak of around 10% of gain from the machines alone since the EPO years.
The two sides of the line
On one side, the skeptics. For them, the shrinkage of the gap from 14% to 6% is too large to be explained by food and aerodynamics alone. If every performance above 6.10 W/kg before 2013 had a doped owner, they argue, returning to this territory demands the same skepticism, especially with gray practices like carbon monoxide and sodium bicarbonate on the table.
On the other side, those defending the current era. Travis Tygart, head of the United States anti-doping agency, sums up the thesis: today the bias favors the clean athlete, it is possible to win without cheating. On a Pyrenean climb, a doped Lance Armstrong at his peak did about 6 W/kg in 2004 and took almost six minutes more than Pogacar on the same mountain. The difference, they say, is the sum of legal gains plus much stricter controls: the biological passport, the whereabouts system and longitudinal profiles that did not exist in the 1990s.
What the best evidence really says
The honest answer is uncomfortable for both sides. Physiology, on its own, proves neither guilt nor innocence. Pogacar's and Vingegaard's numbers are plausible at the human biological limit, and that is exactly why they remain suspicious: they live in the zone where rare talent and illegal gain produce similar results on paper.
Three cautions help read the debate without falling into fair-weather fandom. First, almost every W/kg quoted is an estimate, not a measurement, and comes with error that changes the verdict. Second, comparing eras without discounting aerodynamics, nutrition and equipment artificially inflates suspicion. Third, absence of proof of doping is not proof of cleanliness, and a number at the human limit is not, by itself, a confession. What science delivers, in the end, is a range of uncertainty, not a verdict.
