Think about you start pedaling from the beginning of Stage 17 of this yr’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’ve got 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 may not even be capable of 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 journey. And Stage 17 is only one of 21 levels that have to be accomplished within the 23 days of the tour.
I’m a sports activities physicist, and I’ve modeled the Tour de France for almost 20 years utilizing terrain information — like what I described for Stage 17 — 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 is measured in hours as a substitute of days. The rationale they’re in a position to do what the remainder of us can solely dream of is that these athletes can produce monumental quantities of energy. Energy is the speed at which cyclists burn power and the power 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 Massive Macs.
Biking Is a Sport of Watts
To make a bicycle transfer, a Tour de France rider transfers power from his muscular tissues, by way of the bicycle and to the wheels that push again on the bottom. The quicker a rider can put out power, the better the ability. This fee of power switch is usually measured in watts. Tour de France cyclists are able to producing monumental 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 execs 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 the entire power a Tour de France bicycle owner places into his bike will get become 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 combat gravity whereas climbing.
I incorporate the entire 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 almost all leisure cyclists could be blissful if they may produce 300 watts for simply 20 minutes!
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McDonald’s
Turning Meals Into Miles
So the place do these cyclists get all this power from? Meals, in fact!
However your muscular tissues, like all machine, cannot convert 100% of meals power immediately into power output — muscular tissues could be anyplace between 2 % environment friendly when used for actions like swimming and 40 % environment friendly within the coronary heart. In my mannequin, I take advantage of a mean effectivity of 20 %. Understanding this effectivity in addition to the power 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 throughout the race — or a mean of almost 6,000 energy per stage. On a number of the tougher mountain levels — like this yr’s Stage 17 — racers will burn shut to eight,000 energy. To make up for these large power losses, riders eat delectable treats resembling jam rolls, power bars and mouthwatering "jels" so they do not waste power chewing.
Final yr’s winner, Tadej Pogačar, weighs solely 146 kilos (66 kilograms). Tour de France cyclists haven’t got a lot fats to burn for power. They should hold placing meals power into their our bodies to allow them to put out power at what looks as if a superhuman fee. So this yr, whereas watching a stage of the Tour de France, notice what number of occasions the cyclists eat — now you recognize the rationale for all that snacking.
This text is republished from The Dialog below a Inventive Commons license. You’ll find the unique 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.
