### The Physics of Everesting: Can a Tailwind Really Make a Difference?
In recent times, the cycling community has experienced a rise in interest regarding a demanding challenge referred to as “everesting.” The idea is straightforward yet intimidating: cyclists ascend and descend a hill repeatedly until their cumulative elevation gain matches that of Mount Everest—8,848 meters (approximately 5.5 miles). While this challenge has captured the attention of numerous enthusiasts, a fresh debate has arisen about whether a significant tailwind can markedly enhance a rider’s performance time. Physicist Martin Bier from East Carolina University has explored this topic in a recent publication in the *American Journal of Physics*, and his conclusions might astonish you.
#### What is Everesting?
The term “everesting” emanates from George Mallory, the grandson of the renowned British mountaineer George Mallory, who was involved in early 20th-century Mount Everest expeditions. In 1994, the younger Mallory prepared for his individual Everest endeavor by cycling up and down Mount Donna Buang in Australia until he ascended the height equivalent to Everest.
Fast forward to 2014, when Australian cyclist Andy van Bergen elevated the concept to a worldwide scale by organizing “everesting” events where participants could select a hill close to their residences and monitor their progress online. The challenge gained further momentum during the COVID-19 pandemic as lockdowns restricted other avenues for physical activity.
For the majority of cyclists, accomplishing an everesting attempt requires more than 20 hours. However, professional cyclists can complete the challenge much quicker. Irish cyclist Ronan McLaughlin set a benchmark in July 2020, finishing the challenge in just 7 hours, 4 minutes, and 41 seconds. He later surpassed his own record in March 2021, completing it in 6 hours, 40 minutes, and 54 seconds on the same hill—Mamore Gap in Ireland.
#### The Role of Wind: Does It Truly Assist?
McLaughlin’s second record-setting ride in 2021 experienced a tailwind of roughly 12 mph (5.4 m/s), igniting speculation within the cycling community. Could the tailwind have been pivotal to his enhanced performance time? Some even posited that the everesting regulations should be amended to restrict the wind speeds permitted for record-setting attempts.
To investigate this, Bier assessed McLaughlin’s rides through the lens of physics, concentrating on the wind’s effects on both the ascents and descents of the route. The Mamore Gap route spans 810 meters with a 117-meter elevation gain, and McLaughlin completed 76 laps to meet the required elevation.
#### The Bicyclist’s Paradox
Bier’s examination centers around a concept known as the “bicyclist’s paradox,” which frequently arises in physics discussions. The paradox postulates that if a cyclist travels up a hill and descends back down, with no net change in elevation, the speeds should offset each other. However, this does not hold true in reality, primarily because of air resistance.
When ascending, air resistance is minimally influential, allowing cyclists to concentrate on maximizing their power output. Conversely, during descents, air resistance becomes considerably more impactful. The force of air friction escalates with the square of the cyclist’s speed, indicating that doubling one’s speed demands four times the power, and tripling it necessitates nine times the power. This results in a scenario where the cyclist’s downhill velocity is constrained by air resistance, despite exerting less effort.
Bier discovered that while a tailwind may offer some advantage during the ascents, the resultant headwind during the descents poses a much greater negative consequence. Indeed, the headwind adds approximately 12 seconds to each lap due to the time required to accelerate to terminal speed on the descent.
#### The Impact of Lap Length
One of Bier’s significant observations is that the hill’s length substantially influences the overall time. On McLaughlin’s route, each lap was relatively brief, necessitating 76 instances of acceleration downhill. If the hill had been twice as long, he would have needed to accelerate downhill only 30 times, potentially saving him over seven minutes in total. Bier characterized the additional 12 seconds per lap as “the cost incurred for a shorter lap.”
#### Physiological Factors
Bier’s model primarily concentrated on the physics of wind and air resistance, yet he recognized that physiological aspects also contribute to everesting performance. McLaughlin’s record-setting ride consisted of five-minute laps, with four minutes allocated for climbing and one minute for descending. The brief downhill segments offered regular recovery intervals, enabling McLaughlin to sustain a higher power output during ascents than he could have maintained continuously.
Bier proposes that there may be an ideal time frame for alternating between effort and rest, which could differ from athlete to athlete.
