Since the beginning of the 20th century, three-week tour races have been extremely demanding. Compared to the old days, the current trend is toward shorter, more intense daily stages. In the years to come, it is expected that the average amount of time a cyclist spends in zone 3 per stage will be more than 30 min.
Physiological Demands of the Different Phases of Tour Races
In general, three-week tour races have three main competition requirements: flat and long parcours (usually ridden at high speeds inside a large group of riders), individual time trials (40 to 60 km over level terrain), and uphill cycling (high mountain passes).
Every tour race includes seven or more flat stages of about 200 km, lasting four to five hours. Most of the time, cyclists ride in large groups of 150 to 200 cyclists. This considerably reduces the major force—air resistance—to be overcome in this type of terrain. As a result, the energy requirement of cycling can be decreased by as much as 40% (McCole et al. 1990), making the overall exercise intensity low to moderate. The proportion of the total stage time spent in zone 3 barely reaches 5% (Lucia, Hoyos et al. 1999).
A great mastery of technical skills (such as drafting or the ability to avoid crashes) would seem most important in this type of stage, in which most riders are able to finish within the same time. In fact, these stages usually do not determine the final outcome of a tour race.
The high average speeds (approximately 45 kph) at which riders are able to cover these stages require that they push high gears (53 X 12 to 11) during long periods. This inevitably results in some muscle damage. Previous research has reported increased levels of muscle damage markers during cycling tour races (Mena, Maynar, and Campillo 1996). This phenomenon may have a negative impact on performance during the second part of a three-week race, during which accumulated muscle fatigue may considerably limit performance in the phases of competition that determine the winner—the time trials and high mountain passes.
Tour races typically include three time trials (TT) performed over overall flat terrains: a short, opening TT of 5 to 10 km and two long TT of 40 to 60 km. This phase of the competition usually influences the final outcome of the race.
Air resistance is the main force that the cyclist encounters during TT. Thus, aerodynamic factors (the cyclist’s riding posture, the size of the frontal wheels, etc.) play a major role (Lucia, Hoyos, and Chicharro 2000a).
Those who seek top performance (average velocity of 50 kph) must tolerate high constant workloads, mostly in zone 3, during the entire 60 min of the TT (Lucia, Hoyos et al. 1999). Some authors have estimated that the mean absolute power output sustained during long TT averages 350 W, although TT specialists probably generate much higher power outputs (greater than 400 W) (Padilla et al. 2000).
Some mass-start stages of approximately 200 km (the so-called high mountain stages) include three to five mountain passes of 5 to 10% mean gradient, and thus require cycling uphill during several 30- to 60-min periods over a total time of five to six hours.
When climbing at low speeds (about 20 kph), the cyclist must mainly overcome the force of gravity (Swain 1994). Because of its effects on gravity-induced resistance, body mass has a major influence on climbing performance. A high power-output-to-body-mass ratio at maximal or near-maximal intensities (6 or more W/kg) is necessary for professional road riders (Lucia, Hoyos, and Chicharro 2000a; Padilla et al. 1999).
In addition, rolling resistance resulting from the interaction between the bicycle tires and the road surface increases considerably at lower riding speeds and on the rough road surfaces of most mountain routes (Lucia, Hoyos, and Chicharro 2000a). To overcome these forces, cyclists frequently switch from the conventional sitting position to a less economic standing posture to exert more force on the pedals. Climbing specialists perform high mountain ascents at intensities in zones 2 and 3 (Fernández-García et al. 2000; Lucia, Hoyos et al. 1999). Because of team requirements, however, some riders are not required to perform maximally during high mountain stages.
This is an excerpt from High-Tech Cycling.