What's Cool In Road Cycling

Le Tour Toolbox – Checking the Engine

The beauty of cycling is that we can ride pretty much the same things as the pros, and also ride the same routes as them. If only we had their engine to go with it. Here are some things to look at from a physiological perspective as the vortex that is Le Tour sucks us ever tighter into its grip…

The Human Food Processor
The amount of energy expenditure is simply astounding. In a classic study in 1989, scientists closely tracked the energy consumption and expenditure of 5 cyclists during the Tour (1). The typical Tour rider consumed a daily average of 24.7 MJ of energy (6000 Kcal), peaking at 32.4 MJ (7700 Kcal). In contrast, the average daily caloric intake for a young adult male is about 2,000 – 2,500 Kcal. To give this some perspective, gorging on a big massive turkey dinner that leaves you absolutely bursting at the seams and wanting to do nothing but nap is probably 3,500 Kcal. Just the physical ability to consume and process 3 – 4 times more calories than a normal individual for weeks upon weeks, without contracting gastrointestinal problems, is an amazing feat in itself.

Nobody who tries diet fads like Atkins is going to survive at Le Tour. The average breakdown of protein, carbohydrates, and fats of the five riders were 15, 62, and 23%, respectively, pretty much identical to a “normal” athletic diet. I’ll blast Atkins and other diet fads some other day, but at the heart of those diets, regardless of the window dressing like “carbs are bad” or “zone” that they put over it, is hypocaloric energy consumption well below typical requirements. This makes it especially difficult to recover from strenuous efforts in training or competition.

In order to consume so many calories, up to 49% of the energy intake occurred on the bike itself in the form of carbo-electrolyte drinks and food, resulting in a high proportion of the daily total of carbohydrates being consumed on the road. This is essential because carbohydrates are the most readily-processed fuel you can ingest, and a constant intake spares the use of your very limited glycogen (the storage form of carbohydrates in your body) stores. Once your glycogen supplies are depleted, you’re running literally on fumes – the carbohydrates that you’re ingesting – with no safety net before the dreaded “bonk” hits. The old adage of “drink before you’re thirsty, eat before you’re hungry” definitely applies, because time is required to process the food and drink before it gets into your system.

Straight to the Heart
Polar, the heart rate monitor people, has a
website showing heart rate profiles of select riders
during the 2003 Tour (they’re promising to update it throughout this year’s event, so check it out!). The neat one for me was Servais Knaven (Quick-Step Davitamon) during his winning ride to Bordeaux in Stage 17. After literally all day (the break formed in the first kilometer!) in a break of 10 riders , the 2001 Roubaix winner broke away from his companions and soloed home the last 18 km.

What stuck out for me was how Knaven’s heart rate profile remained soooooooo low for the entire duration of the break, staying at about 140 bpm even while averaging over 50 km/h over the first hour and a total average of >46 km/h over the 180 km stage. The smoothness of the HR profile is likely due to a very smoothly operating breakway group, short pulls at the front, and also probably a slight tailwind, such that major spikes while at the head of the break were not evident. Regardless, the low HR during such a sustained break is still a sign of amazing fitness and a testament to hours and hours of endurance and tempo training.

The other fascinating segment of the HR profile was during the final 18 km solo move, where the HR instantly leapt to about 180 bpm and stayed there the entire final move. Obviously there is simply nowhere to hide when you’re in a do-or-die solo move, and Knaven pegged his effort right at his threshold for a very painful 20+ minutes.

The ability to make these extreme efforts after 160 km of racing is what separates the pros from even top-level amateurs. While most of us can feel our batteries running low after a certain number of kilometers in our legs, the pros will often train specifically for these late efforts by timing their intervals or motorpacing efforts for the later parts of their ride. As one elite swim coach I work with likes to say, “the fastest swimmers slows down the least.” He follows the same principles with his swimmers, putting the most emphasis (psychologically, physiologically and technically) on the intervals at the back end of the workouts.

Le Tour Toolbox!
Your Toolbox crew has a slate of Tour features coming up over July to put you into proper overdose mode. Next week, Frank “Papa FasCat” Overton will have a special feature on aerodynamics and Lance’s F-One project. Bruce will be talking with the pros about the intricacies of stage racing.

As for me, I’ll be smack dab roadside of Le Tour itself to put all my theory into practice following the race and dragging my carcass over the Pyrenees and Alps! Stay tuned for both Toolbox and roadside articles over July, and make sure you get out on the bike in between gorging on Le Tour!

1. Saris, W.H. et al. Study on food intake and energy expenditure during extreme sustained exercise: the Tour de France. Int. J. Sports Med. 10: S26-31, 1989.

About Stephen:
Stephen Cheung is an Associate Professor of Kinesiology at Dalhousie University in Halifax, Nova Scotia, Canada, and is rationing himself to only one serving of poutine (French fries, gravy, and cheese curd!) and tiramisu a day in hopes of surviving the Tour. His company, Podium Performance, also provides elite sport science and training support to provincial and national-level athletes in a number of sports. He can be reached for comments or coaching inquiries at [email protected].

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