Martin Beer
Recently, many avid cyclists have joined the “Everest climbing” trend. This is a type of cycling that involves climbing up and down the same mountain trail over and over again until the total distance climbed is 100km. Everest: 8,848 meters or about 5.5 miles. There has been some discussion recently about whether a strong tailwind helps a rider improve their time. However, it seems that this is not the case. New Paper Physicist Martin Beer of East Carolina University in North Carolina published the findings in the American Journal of Physics.
The word “Everesting” was coined in the 1920s after George Mallory, the grandson of the legendary mountaineer. George Mallory He took part in the first three British Everest expeditions. Mallory the Junior was preparing for his Everest attempt in 1994 and his training included multiple weekends cycling up Mount Donna Buan in Australia before summiting Everest.
Two decades later, another Australian cycling enthusiast, Andy van Bergen, began organising a global “Everest” event, where cyclists would pick a hill close to home and record each other’s progress online. The event became hugely popular after the COVID-19 pandemic led to global lockdowns in 2020.
Beer says that it would typically take an averagely fit cyclist more than 20 hours to complete such a feat, but professionals can do it much faster. For example, Irish cyclist Ronan McLaughlin completed the challenge on July 30, 2020 in 7 hours, 4 minutes and 41 seconds, and then improved his own record on the same hill (Mamore Gap, Ireland) in March 2021, completing the challenge in 6 hours, 40 minutes and 54 seconds.
Beer used McLaughlin’s record-setting ride for his analysis. The route McLaughlin used was an 810-meter road section, including a 117-meter climb. While the wind was not very strong on McLaughlin’s first attempt in 2020, on his second ride in 2021 he had a tailwind of about 12 mph (or 5.4 m/s). The significant improvement in his time has led to much “qualitative speculation” in the cycling community about the extent to which the tailwind contributed to his “Everest” record, with some considering whether a rule change is needed to limit the wind speed allowed to determine future Everest records.
The cyclist’s paradox
Beer points out in his paper that the same tailwind would have been a headwind on McLaughlin’s descent. So the question is whether the impact of a strong tailwind going uphill was greater than the headwind going downhill. In physics education, there’s a concept known as the “bicyclist’s paradox.” When cycling uphill and downhill, with no net change in elevation, one might intuitively expect that the uphill and downhill speeds should cancel each other out.
In reality, this isn’t the case – mainly due to aerodynamics. Indeed, aerodynamics is a negligible factor when cycling uphill. That’s why experienced cyclists try to double their power output/speed when cycling uphill. However, the force of aerodynamics grows as the square of your speed. To double your speed, you need four times the force, to triple your speed, nine times the force. Beer says“It will cause chaos”
Beer found that while a tailwind might help a little on the way uphill, a headwind has a big effect on the way downhill. In fact, it takes longer to accelerate up to terminal velocity on the way downhill, which adds about 12 seconds to your lap time. Running longer laps could potentially improve your time to summit Everest. For example, summiting Everest on a hill twice as long as McLaughlin’s Mamoa Gap route would require just 30 downhill accelerations instead of 76, adding just over seven minutes to your time. Beer described the 12-second increase as “the price you pay for a shorter lap.”
In building his model, Beer did not take into account physiological factors, particularly the fact that McLaughlin’s record-breaking race was a five-minute lap, four of which were uphill and one minute downhill. “Because of periodic rest periods, power output during a four-minute bout may be higher than the power output that could be sustained uninterrupted,” Beer wrote. “There is likely an optimal time interval if each bout is followed by a rest period of approximately one-quarter of the exercise time. Moreover, optimal intervals may vary from athlete to athlete.”
But “overall, there is no physical justification for altering the rules of Everest to limit permissible wind speeds,” Beer concluded. “The controlled analysis ultimately tells us that the most intuitive way to improve time on Everest – losing weight and increasing power – is indeed the most effective way. There is no clever way to circumvent the necessary diet and exercise.”
American Journal of Physics, 2024. DOI: 10.1119/5.0131679 (About DOIs)
