“Tour de France riders Oliver Naesen of Belgium and Michael Schär of Switzerland should eat continuously to replenish the vitality they burn. Tim de Waele/Getty Photos
Think about you start pedaling from the beginning of Stage 17 of this 12 months’s Tour de France. First, you’d bike roughly 70 miles (112 kilometers) with a gradual improve in elevation of round 1,300 ft (400 meters). However you have but to hit the enjoyable half: the Hautes-Pyrénées mountains.
Over the subsequent 40 miles (64 kilometers) you would need to climb three mountain peaks with a web improve of a mile (1.6 kilometers) in elevation. On the fittest day of my life, I won’t even have the ability to end Stage 17 — a lot much less do it in something remotely near the 5 hours or so the winner will take to complete the experience. And Stage 17 is only one of 21 levels that should be accomplished within the 23 days of the tour.
I’m a sports activities physicist, and I’ve modeled the Tour de Francefor practically twenty years utilizing terrain knowledge — like what I described for Stage 17 — and the legal guidelines of physics. However I nonetheless can not fathom the bodily capabilities wanted to finish the world’s most well-known bike race. Solely an elite few people are able to finishing a Tour de France stage in a time that is measured in hours as a substitute of days. The rationale they’re capable of do what the remainder of us can solely dream of is that these athletes can produce huge quantities of energy. Energy is the speed at which cyclists burn vitality and the vitality they burn comes from the meals they eat. And over the course of the Tour de France, the profitable bicycle owner will burn the equal of roughly 210 Large Macs.
Biking Is a Sport of Watts
To make a bicycle transfer, a Tour de France rider transfers vitality from his muscular tissues, via the bicycle and to the wheels that push again on the bottom. The quicker a rider can put out vitality, the larger the facility. This charge of vitality switch is commonly measured in watts. Tour de France cyclists are able to producing huge quantities of energy for extremely lengthy intervals of time in comparison with most individuals.
For about 20 minutes, a match leisure bicycle owner can persistently put out 250 watts to 300 watts. Tour de France cyclists can produce over 400 watts for a similar time interval. These professionals are even able to hitting 1,000 wattsfor brief bursts of time on a steep uphill — roughly sufficient energy to run a microwave oven.
However not all the vitality a Tour de France bicycle owner places into his bike will get was ahead movement. Cyclists battle air resistance and frictional losses between their wheels and the highway. They get assist from gravity on downhills however they should struggle gravity whereas climbing.
I incorporate all the physics related to bicycle owner energy output in addition to the consequences of gravity, air resistance and friction into my mannequin. Utilizing all that, I estimate {that a} typical Tour de France winner must put out a mean of about 325 watts over the roughly 80 hours of the race. Recall that the majority leisure cyclists could be completely satisfied if they may produce 300 watts for simply 20 minutes!
“In the course of the course of the Tour de France, the profitable bicycle owner will burn the equal energy of roughly 210 Large Macs.McDonald’s
Turning Meals Into Miles
So the place do these cyclists get all this vitality from? Meals, after all!
However your muscular tissues, like several machine, cannot convert 100 p.c of meals vitality straight into vitality output — muscular tissues could be anyplace between 2 p.c environment friendly when used for actions like swimming and 40 p.c environment friendly within the coronary heart. In my mannequin, I exploit a mean effectivity of 20 p.c. Realizing this effectivity in addition to the vitality output wanted to win the Tour de France, I can then estimate how a lot meals the profitable bicycle owner wants.
Prime Tour de France cyclists who full all 21 levels burn about 120,000 energy in the course of the race — or a mean of practically 6,000 energy per stage. On among the harder mountain levels — like this 12 months’s Stage 17 — racers will burn shut to eight,000 energy. To make up for these large vitality losses, riders eat delectable treats akin to jam rolls, vitality bars and mouthwatering "jels" so they do not waste vitality chewing.
Final 12 months’s winner, Tadej Pogačar, weighs solely 146 kilos (66 kilograms). Tour de France cyclists haven’t got a lot fats to burn for vitality. They should preserve placing meals vitality into their our bodies to allow them to put out vitality at what looks like a superhuman charge. So this 12 months, whereas watching a stage of the Tour de France, word what number of occasions the cyclists eat — now you realize the explanation for all that snacking.
This text is republished from The Dialog beneath a Inventive Commons license. You will discover the authentic article right here.
John Eric Goff is a professor of physics on the College of Lynchburg the place he researches the physics of sports activities.