Imagine. The Tour is well underway this time in France and is approaching July 14th. You are at the beginning of the twelfth stage, a mountain stage … Your first task will be to cover 33.2 kilometers to the Col du Galibier, in the French Alps, gaining approximately 1,305 meters of elevation gain.
But this is only the first of the three great climbs of your day, with a total of approximately 3,050 meters of elevation gain. Because then you will face the top of the Croix-de-Fer pass and finish the 165.1-kilometer stage on the famous Alpe d’Huez climb with its twenty-one winding turns.
Even at my best, I might not be able to finish this twelfth stage. Even less to do so in a time that would approach the five and a few hours it will take the winner to cross the finish line. And this twelfth stage is just one of twenty-one to be completed during the twenty-four days of the Tour.
I am a sports physicist and have been modeling the Tour de France for almost two decades using terrain data, such as the one given here for stage 12, and the laws of physics and physiology. But I still can’t fully understand the physical skills needed to complete the world’s most famous cycling race.
Only a small sports elite is able to complete a stage of the Tour de France in a time that is measured in hours, not days … The reason they are able to do what the rest of us can only dream of is that these athletes can produce large amounts. of power.
Power is the speed at which cyclists are able to burn energy, and the energy they burn comes from the food they eat. During the Tour de France, the winning cyclist will burn the equivalent of about 210 Big Macs (about 550 kcal per sandwich).
To advance a bicycle, a Tour de France runner (like any cyclist) transfers, through the bicycle, the energy of his muscles to the wheels that push the ground and propel it. The faster a runner is able to produce energy, the greater its power. This energy transfer rate is usually measured in watts.
Tour de France cyclists are able to generate huge amounts of energy over incredibly long periods of time compared to most people.
For about twenty minutes, a recreational cyclist in good physical condition can consistently produce between 250 and 300 watts. Tour de France cyclists can produce more than 400 watts during the same period. These professionals are even able to reach 1,000 watts for short periods of time, such as on a steep climb, about enough power to run a microwave oven.
But not all the energy a cyclist puts on his bike is transformed 100% into forward motion. There are losses: these athletes have to fight air resistance and friction losses between their wheels and the road. And if you have the help of gravity in the descents, you have to fight it in the sometimes exhausting climbs.
To power and rotate my model, I incorporate all the physics associated with rider power, as well as the effects of gravity, air resistance, and friction. With all of this, I estimate that a typical Tour de France winner would have to deliver an average of about 325 watts during the roughly eighty hours of racing. Remember that most recreational cyclists are happy when they manage to produce 300 watts for just twenty minutes!
Turns food into miles
So where do these exceptional cyclists get all this energy from? The food, of course!
But their muscles, like ours and like any other machine, cannot convert 100% of the energy of food into energy produced. Again, there is loss. Muscles can perform between 2% for activities such as swimming and 40% for the heart (which is also a muscle).
In my model, I use an average efficiency of 20%. Knowing this efficiency, as well as the energy production needed to win the Tour, I can estimate how much food the winning cyclist needs.
On average, the most successful cyclists on the Tour, those able to complete the twenty-one stages in the best times, will burn about 120,000 calories during the race, or an average of almost 6,000 calories per stage. But in some of the toughest mountain stages, like this year’s famous twelfth stage, the slide is close to 8,000 calories!
To make up for these huge energy losses, runners eat delicious delicacies such as jams, energy bars and tasty jellies … so as not to waste energy chewing them.
Tadej Pogačar, who won the 2020 and 2021 editions of the Tour de France, weighs only 66 kilos. In fact, what’s striking about their sharp silhouettes is that these cyclists don’t have too much fat to burn to generate energy. Without reservations, they must therefore provide energy (food) continuously to their body in order to be able to expend it almost immediately, at a rate that seems superhuman.
This year, looking at a stage of the Tour de France, look at the number of times cyclists eat; now you know the reason for all this snack.
This article is republished from The Conversation under a Creative Commons license. Read the original article.