Why are responses to an attack in a cycling race immediate?

Question

There may be a trivial, or merely a psychological, answer to this question.

When someone with ambitions to win the race attacks, i.e. sprints ahead of their group, those also aspiring to win the race immediately respond to the attack.

If the race has hundreds (or thousands) of kilometres remaining — as is often the case — why the rush? Why does the response have to come at a timing chosen by the attacker? Perhaps the attacker felt a sudden rush of power in their legs, which may well be a unique fluke to their physiology (or their state of mind at that moment, or their specific perfect nutrition that morning, etc), and responders are not at their peaks at that very moment. Could they not bide their time, and attack later ("surreptitiously")? (With every rider wearing headphones, no attack can ever actually be surreptitious — but a gradual rather than a sudden attack would come close.)

I understand that they're often attempting to draft off the leader, which greatly reduces their power needs to maintain the same speed and remain close to the leader. Is there any other, deeper reason why the response to attacks is always so swift?

Disclaimer: I've never raced, which is perhaps why the answer may be trivial or just psychological. (I'm starting to suspect that reaching the upper limits of one's ability—or DNA—can only be achieved through racing — and so for example there is no point bemoaning that at a certain level of group riding it's all about racing, as racing and training are two sides of the same coin — but that's an entirely different topic.)

Edit

To be very specific, why did Jonas Vingegaard immediately respond to Tadej Pogačar's attack during TdF 2024? They're still in Stage 2, and JV has thousands of kilometres to catch up.

Answer 1

This answer considers only General Classification (GC) contestants in a stage race, like Tour de France. If you want to win the GC, for every other rider finishing the race, you must beat them in at least one stage (it does not have to be the same stage for every other rider, though, i.e. you don’t need to win any stage, but you must beat each of your rivals in at least one stage). So when somebody in the GC contest attacks, the others have to make a choice: do I follow or do I let him go. If you let him go, you must win the time back in some other stage, i.e. you must attack in some other stage so that he does not follow you (or you must win the time in time trial). Attacking is always harder than following, due to the drafting effect, so if you let him go now, you must do more work in some later part of the race to win the time back. Hence, if you can, it’s almost always a good idea to follow just from pure “watts spend” point of view.

And there are also the other riders contesting for the GC. Especially in the early phases of a grand tour, the time gaps between the top riders are very small. Winning some time against the others might be very useful if on a later stage you get a mechanical or simply have a bad day. Or maybe you think you are better time trialist than the attacker, but by joining his attack, you both can distance even better time trialist thus giving you some safety margin (something which was believed to be the case between Tadej Pogačar (the attacker), Jonas Vingegaard (the follower), and Remco Evenepoel (who could not immediately follow) in 2024 TdF stage 2). And if everybody follows the attack, as often happens, everybody does the same extra work (except the first attacker, who does more work, again due to the drafting).

As Weiwen Ng mentions, there’s also the psychological effect. The attacker might get a psychological boost knowing that you don’t seem to be able to follow them. And conversely, it might hurt you and your teammates’ morale if you get dropped. Professional endurance sports are very much about your mental strength and how deep you can push yourself. You don’t typically want to give your opponent any advantage on the mental side, either.

There are cases when you don’t want to follow, though. If you can’t, you can’t, and you should aim to minimise your losses. In 2023 TdF, Pogačar did many attacks that Vingegaard wasn’t able to follow. But he minimised his losses and often crossed the finish line just seconds behind Pogačar, eventually beating him in TT and in big mountain stages towards the end of the race. In long mountain climbs you often just want to stick to your maximum sustainable power, knowing that it is the fastest way up. Or maybe you want to save some energy for the next day(s), especially if the stage finish is not at the top of the climb and you trust you are better at the remaining part of the stage.

In summary, if you see a GC contestant attacking, you shouldn’t wonder if the others follow — it’s the most efficient thing to do — but you should wonder if they don’t.

Answer 2

One element of physics favors an immediate response, all else equal: the draft behind a cyclist declines very rapidly with distance. If you want to catch on to an attack, an immediate response is optimal. If you delay until someone is a hundred meters up the road, you now have to expend much more energy to catch them. That explains why in the general case of a breakaway, people who want to try to get into that breakaway should respond as early as possible. That said, the breakaway might not last, and there might be another selective terrain feature closer to the finish that could favor a breakaway.

General classification factors in responding

Let's talk about the general classification (GC) race, that is for overall victory. At the top level, the physiological gaps between top athletes are very small. When you see gaps of multiple minutes in the grand tours, those are the product of differences over many days - 21 for the men.

Psychology is one factor. Absolutely no amount of positive psychology could even let me finish the Tour in the grupetto, but it is still at play in the GC. Kit Nicholson of the Escape Collective argued that Pogačar's attack on stage 9 (the stage with gravel sectors) was in part to try to land a psychological blow. An immediate response might similarly be motivated by wanting to show that you're close or equal to the attacker.

The draft is still at play, even on climbs. Bonus seconds for the top three placings might be at play, although they weren't in stage 2. You might also want to put time on the other contenders. And there's uncertainty at play, because you don't know how much time the other rider may take. Hence, you might want to stay close.

In other GC contexts, you're right that you might not want to respond immediately to an attack by someone else contending for GC. You might be able to handle variable power more poorly than the other rider. If you are at your limit, going further above your threshold will be costly. You might accept some time loss if you know you can make it up in the time trial, and Vingegaard is thought to be better at TTs than Pogačar. Or you might be able to figure that the other rider is riding over their limit and they could crack - I don't know how often that happens these days, but this could be more of an issue before power-based training.

Vingegaard in 2024 is also a special case, because his preparation is impaired due to an earlier injury. He might be thinking that the effort would help him race into shape - he would be fresher than others, in some ways, so that might be an acceptable risk. Or it's also a gauge of form. Indeed, the media are taking his performance as a positive sign.

Answer 3

There are a lot of factors. In a stage race like the Tour de France, winning on general classification doesn't necessarily require you to win every stage (or, theoretically, any stage), but there's still a great deal of prestige attached to a stage win, and it's harder to win a stage if you're not at the front.

A lot of attacks do go unanswered. Sometimes the rest of the peloton judges the attacker to have no chance of staying ahead of the field—perhaps because the attacker isn't strong enough, or went out too early. Eventually the peloton may reel in the attacker. And perhaps the attacker knows all this, but is trying to get a few minutes of glory and exposure for the team sponsors.

Sometimes a serious contender makes an attack that is not answered immediately, but other contenders in the pack will organize a chase group and bridge up. Or sometimes a contender tries to organize a chase group, but no one else is interested.

In the case of Pogi and Vingegaard, remember that the margin of victory in the TdF, despite being thousands of kilometers long, can be less than a minute, as it was in 2020, when Pogi bested countryman Primož Roglič by 59 seconds. They are both top contenders, and they both know they can't afford to waste a second.