Think about you start pedaling from the begin of Stage 12 of this yr’s Tour de France. Your very first activity can be to bike roughly 20.6 miles (33.2 km) as much as the height of Col du Galibier within the French Alps whereas gaining round 4,281 ft (1,305 m) of elevation. However that is solely the primary of three massive climbs in your day. Subsequent you face the height of Col de la Croix de Fer after which finish the 102.6-mile (165.1-km) stage by taking up the well-known Alpe d’Huez climb with its 21 serpentine turns.
On the fittest day of my life, I won’t even be capable to end Stage 12—a lot much less do it in something remotely near the 5 hours or so the winner will take to complete the journey. And Stage 12 is only one of 21 levels that have to be accomplished within the 24 days of the tour.
I’m a sports activities physicist, and I’ve modeled the Tour de France for practically twenty years utilizing terrain information—like what I described for Stage 12 – and the legal guidelines of physics. However I nonetheless can’t 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’s measured in hours as an alternative of days. The explanation 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 successful bike 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 muscle tissues, by means of the bicycle and to the wheels that push again on the bottom. The sooner a rider can put out vitality, the better the facility. This price of vitality switch is usually measured in watts. Tour de France cyclists are able to producing huge quantities of energy for extremely lengthy durations of time in comparison with most individuals.
For about 20 minutes, a match leisure bike 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 watts for 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 bike owner places into his bike will get become ahead movement. Cyclists battle air resistance and frictional losses between their wheels and the street. They get assist from gravity on downhills however they must battle gravity whereas climbing.
I incorporate all the physics related to bike owner energy output in addition to the results 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 almost all leisure cyclists can be pleased if they may produce 300 watts for simply 20 minutes!
Turning meals into miles
So the place do these cyclists get all this vitality from? Meals, after all!
However your muscle tissues, like all machine, can’t convert one hundred pc of meals vitality immediately into vitality output—muscle tissues may 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. Figuring out this effectivity in addition to the vitality output wanted to win the Tour de France, I can then estimate how a lot meals the successful bike 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 yr’s Stage 12—racers will burn shut to eight,000 energy. To make up for these large vitality losses, riders eat delectable treats corresponding to jam rolls, vitality bars, and mouthwatering “gels” so that they don’t waste vitality chewing.
Tadej Pogačar received each the 2021 and 2020 Tour de France and weighs solely 146 kilos (66 kilograms). Tour de France cyclists don’t have a lot fats to burn for vitality. They must hold placing meals vitality into their our bodies to allow them to put out vitality at what looks as if a superhuman price. So this yr, whereas watching a stage of the Tour de France, notice what number of instances the cyclists eat—now you understand the explanation for all that snacking.
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