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Pacing on the bike: How best to manage power

What is the best way to manage energy? Pedal steadily or with acceleration, accelerate on the flat or uphill? Whether you prefer short or long distance, we have tips that will make you faster on any route.

At the start of every race, there is no lack of energy. Or at least, almost. But does it make sense to push to the maximum right away? Or is it better to hold back a little and only give it your all afterwards? And what happens when the course rises and falls, when the wind blows sometimes from in front and sometimes from behind? Where do you use power most effectively?

Pacing is the English term for the division of speed. The art of optimally distributing power is a decisive factor in any cycling discipline. The right pacing becomes particularly evident in time trials, when no opponent can interfere with one’s calculations and no wake can distort the result. In this context, ‘time trial’ also includes mountain marathons or stage races such as the Transalp, which are formally a series of (mountain) time trials and are therefore subject to pacing strategies. The common denominator is to achieve the best possible time over the respective distance.

Physiology

How far do you get if you start with a sprint and then give it your all? About 1,000 metres. After 90 seconds at the most, you will be hanging from the handlebars, exhausted and panting, with cemented legs. If you wanted to keep pedalling, you would have to set a very relaxed pace before you could push again. You could achieve an optimal time over 1,000 metres, but not over longer distances.

The rapid decline after such a short time is in stark contrast to the ability to pedal relatively fast for many hours. The reason is the extreme dynamics of the human motor. Much higher power can be achieved for a short time than for a long time, but this also leads more quickly to a loss of power, due to the different methods of energy supply.

An essential element of pacing is therefore experience. It is necessary to develop an idea of how long one can sustain a certain level of intensity. The brain plays the most important role in pacing. It is here that all the information provided by the body’s numerous sensors (heartbeat, breathing, muscle condition, temperature, etc.) flows together. The result is the perceived effort.

The South African sports scientist Ross Tucker has developed a model that explains how the body unconsciously finds the right rhythm. According to Tucker’s model, expected and perceived effort are constantly compared on the basis of experience. In the process, the expectation is adjusted to the remaining distance to the goal. Basic rule: avoid total collapse!

It is a race on a razor’s edge: just an extra tick and you go too far, one tick less and you fall short. When the goal is in sight and the end of the effort comes, the body releases all its resources for the last effort.

Intensive sport is a play on the body’s protective mechanisms. The feeling of exertion should prevent putting ourselves in danger. The body always tries to hold back reserves for a real emergency. In addition to physiological limits and the will to overcome them, there is also the pure physics of riding. It describes what external forces act on the rider and what consequences, for example, energy consumption has.

The physics

A central role in cycling is played by air resistance, which increases disproportionately with speed (twice the speed requires eight times the power) – in contrast to uphill resistance, which increases linearly with speed.

This has consequences for energy expenditure and brings us to our first example: a 20 km time trial, of which the first 15 km are flat, while the last 5 km have an average gradient of 7%. Let us assume that our athlete can produce an average of 300 W over this distance. What pace is optimal from an energy point of view?

It is possible to calculate the energy expenditure for different scenarios. Let’s compare an effort of 300 W with 285 W for the flat part of the route and 325 W for the uphill part. Result: with the slower start, the cyclist reaches the finish line 30 seconds faster with the same average power! The prerequisite is the ability to maintain a power of 7% above the average power for the time of the climb – this is realistic, but also depends on the training conditions of the athlete.

The situation is less clear on a winding course with headwind and tailwind. With a headwind and tailwind of 7 km/h each, there is hardly any disadvantage compared to a forced strategy if you use the same amount of power: in this case you can only gain a second if you pedal harder into the headwind (310 W) than with the tailwind (287 W).

However, if you invest more energy in the tailwind than in the headwind, you lose time. Intuitively, most athletes will automatically ride stronger against the wind, especially since with a headwind you stay below your intended speed. In this case, therefore, there is the danger of ‘overpacing’, i.e. investing too much power in the headwind section.

On downhill runs, too, it is not advisable to unleash a lot of power. It is better to accelerate correctly at the start of the descent. The final speed that can be reached depends strongly on the initial speed with which one tackles the descent. If you are able to accelerate up the hill, you can tackle a reasonably steep descent with the same speed as an athlete who climbs the hill more slowly and then pedals continuously at high power (greater air resistance when pedalling). The total energy expenditure is lower for the athlete who accelerates at the right time.

The recovery obtained in this way can be used to accelerate again with more force in the next section, where it counts: uphill or after a bend. The following time trial example illustrates this. For the same overall performance, a cyclist gains 19 seconds over a competitor in the last kilometre of an individual time trial, thanks to a better pace!

pacing Fahrrad 2PEAKThe last kilometre of a time trial: both riders produce an almost identical average power of 400 W. They have the same weight and cover the same distance, mostly uphill. However, runner 2 is 19 seconds faster in the short section! The reason for this result is revealed by the documentation of the pedalling: the recording starts at the top of a hill. After a short descent (speed increases in blue), it climbs steadily to the finish.

Cyclist 1 fails to accelerate correctly on the ridge (1). On the descent, he tries to increase speed too late (2). The result is a low top speed of only 47 km/h on the descent.

Cyclist 2 does better: he accelerates harder at the beginning (3) and then accelerates continuously and in a controlled manner. Top speed: 55 km/h (4) (better timing, better aerodynamics). Rider 2 then picks up much more speed on the climb, which he conquers with 483 watts and 39 km/h. Rider 1 invests 495 W in the ascent, but is unable to make up the speed disadvantage and only climbs at 34.6 km/h.

On short courses and especially on technical courses with many ‘bends’, where there is a lot of acceleration, it is not uniform power that leads to the best overall time, but a skilful mix of acceleration and measured speed.

Long distances

In principle, the pace is easier over long distances than over short distances, which require more dynamism. The longer the distance, the more important the question of long-term energy supply becomes, which requires as constant a performance as possible. In extreme cases, this ‘steady state’ can be maintained for days, for example during efforts such as the Race Across America.

If you face a long marathon, the ideal is to choose your pace so that the mix of carbohydrates (stored and ingested) and fat is sufficient until the end of the race. The pace should be well below the threshold level (where 100 % carbohydrates would be burnt). All actions that put a strain on carbohydrate reserves – sustained maximum pace or harmful time spikes within a minute – are counterproductive. Therefore, the advice is to cycle mostly close to the threshold.

Pace aids are heart rate monitors (which presuppose knowledge of the threshold heart rate) or power meters. It is worth keeping an eye on the devices, especially at the start of long distances. This is because our sense of effort plays tricks on us at this stage.

When all stores are full, there is a feeling that the effort is much less hard than during the race. The fact that the muscles are consuming more glycogen than is useful for overall balance is not perceived by the senses. In order to use resources as efficiently as possible, you must therefore restrain yourself in the beginning. This requires a certain discipline: if during the Transalp you pedal strictly following the power meter, several (sometimes dozens!) cyclists will leave you behind on each climb. However, you will see them again before the end of the climb and often overtake them.

In a stage race, the situation is aggravated by the fact that the race is not over after one day. Performance data from the Transalp show that rides in the highest performance zone pay for at least the next day, and therefore you lose more time overall if you overshoot the pace even once. The ideal pace does not refer to a mountain or a day, but to the whole week!

Road race

When opponents and the slipstream come into play, the pace becomes more complicated. Now you have to adapt your actions to the larger picture. If you want to do well in a road race, however, there is one golden rule: hide! Cyclists who stand with their noses to the wind from the start cannot win, at least over long distances. Energy reserves are limited and in the final stages of a road race glycogen reserves are absolutely necessary. Therefore, the first motto is to conserve them as much as possible. At least if you are able to sprint.

If you are more of a breakaway type, at some point you will have to come out and play your card. But don’t do it half-heartedly, but with charisma, so that the effort is worth it. Otherwise, precious energy is simply wasted.

Conclusion

With the right race planning, you can save time. In principle, the body has a very fine sensor system with which you can properly regulate the pace. However, aids such as power meters and wristwatches can help you in many situations to get a more objective picture of the situation and thus constantly fine-tune your body feel.

Rhythm tips:
  • Accelerate briefly and strongly on the ridges and start the descent with as much speed as possible, and then pedal more easily.
  • Pedal a little harder uphill than on the flat, pedal harder against the wind than with the wind.
  • On uneven time trials, accelerate briefly and hard around bends.
  • Take a lot of speed on climbs.
  • On long distances, keep your heart rate under control and always stay below the threshold level.

 

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