It happens more than you’d think. A young cyclist approaches his coach, excited that he nearly matched the wattage that so-and-so put out on a finishing climb at the Tour. It’s right there in his training data: he’s the next Bradley Wiggins! As a coach, I never want to hurt that enthusiasm; but every time, I feel the need to respond with “go race two weeks straight and then see if you can repeat your Tour-level climb.”
It’s an easy trap and I’ve been caught in it myself. Last year, watching the USA Pro Challenge in 2012, I timed Rory Sutherland’s winning ride up Flagstaff. Gleefully, I slapped on my race wheels a few days later and pinned the climb. I stopped my clock at a respectfully close time, nearly on par with Jens Voigt. It must have been the “Shut Up Legs!” chalked across the road. I felt a huge sense of excitement — which lasted until a few weeks later when I did a five-hour ride and then climbed Flagstaff on more equal terms with Sutherland. He would have been showered and changed by the time I crossed the finish line.
As Sutherland explains it, “at the pro level, it doesn’t matter how hard you can climb in the first 30 minutes, except to hang on. The race is at the end.” Sutherland and his physiologist, Iñigo San Millan, did a lot of work to prepare for that stage. His finishing climb was impressive in its own right, but more impressive was the stamina they built to get there. It took “such an effort to get in the break, stay in the break, and then actually have something left for the climb.”
Coaches often talk about a phenomenon called “cardiac drift.” The idea is that if you sat on a trainer at a set resistance for several hours, your power would be steady, but your heart rate wouldn’t. It would slowly rise over the course of the ride. The physiology behind cardiac drift is complex, but basically our hearts have a progressively harder time delivering blood to our working muscles.
At the same time, another effect is going on called “progressive recruitment.” Each of our muscles is composed of many fibers. However, we rarely use all of those fibers. Riding at a steady, easy tempo you may only use 40 percent of the available fibers in your quadriceps. This means that 60 percent are staying relatively rested until they are needed for that town-line sprint or short, steep climb. As we ride, fibers fatigue and weaken. They can’t produce the same power, so more and more fibers are recruited for the same effort.
Cardiac drift and progressive recruitment are key parts of a larger concept that I refer to as “sustainability.” It’s why you can start a ride at a stunning wattage for a given heart rate, but finish four hours later at the same heart rate and a wattage your grandmother would mock.
Sustainability doesn’t show up on most physiology tests, or even on Strava, but it can win as many races as a good sprint and here’s why. Imagine you and another rider look like twins in a lactate test or hill climb time trial. But, you have better sustainability. At the start of a race you’d both be sitting at the same heart rate using 50 percent of your fibers to stay in the field. You’d be even. But over two hours, your rival would start experiencing much greater drift. By the time you are 10 minutes from the finish, your rival is riding 10 beats per minute higher and using a lot more fibers. You’re now the stronger rider and are going to win the race.
Training the drift
Even at extremely high power outputs, pros like Sutherland don’t experience the same rise in heart rate of amateur cyclists. So, if you’re drifting like a “Fast and Furious” movie, here are a few ideas to improve you sustainability.
Intervals and slow riding are both good at training cardiac drift. Time on the bike, especially during the winter months, makes the biggest and most important difference.
As you get closer to the season, push the last hour of your ride when the fibers are struggling. Cardiac drift makes it important to do your long rides by heart rate, not power. A wattage that puts you in the right zone at the start can be a near time trial wattage by the end of a fatiguing ride.
Weight training improves the resistance of muscle fibers and delays recruitment when riding. Weights or plyometrics will help you in the third hour of your big race. Put an emphasis on working your hip flexors and core — they fatigue first.
Low-cadence riding recruits more fibers and fatigues them faster. If you enjoy feeling like your legs are lead bricks then grind out your next race. Otherwise, train at a high cadence (90 to 100rpm), and race there as well.
Protect your muscles
It’s those final 30 to 40 percent of muscle fibers that win the race. Protect them. Avoid unnecessary efforts and even let yourself slip a bit on climbs in the first half of the race.
Team time trials
These are great during the base phase. Find some flat roads with two or three friends. Do four to eight TTT intervals of 8 to 10 minutes at near race pace. Every interval should be the same pace and each rider should limit his or her pulls to 30 seconds.
These are great intervals to do as the start of the season draws near. Find a 5- to 10-minute climb. Do five to six repeats of the climb at just below your threshold heart rate. The trick is to do the same time with every interval.
As Sutherland points out, “a lot (of sustainability) comes from racing. Before a big race I may be able to last three hours. After I recover from the race, I can last four.” Race smart at important races, but use a few training races or weekday throw-downs to race hard. Attack, cover moves, and get your legs screaming. Then teach them to keep going.
Trevor Connor is a long-time cycling coach and researches both exercise physiology and nutrition at Colorado State University