One year ago I did a medical test and the result was aerobic threshold = 167 and anaerobic threshold = 178. Since then I have been training harder so I suspect the threshold is a bit higher.

So few days ago I did a test consisting on running 10 km quite hard for my fitness. I ran alone on a flat circuit and I managed to run 40:20 with an average HR of 177 (last few km I was running at 3:55/km and got up to 183 HR). The feeling was good, but at the same time I recognise that I probably ran as fast as I could.

Talking with some other athletes they all said 'Oh well if this was during a training, you'd absolutely run below 40 if in a race'. However, that seemed strange to me, since:

  • I ran as fast as I could, probably.
  • My HR were almost the maximum.

But they insist on saying that competition days make people run faster. I am competitive myself and know that I would probably try to go faster if surrounded by other athletes, but at the same time I am curious about what values (HR, speed, resistance to fatigue) would improve in relation to a normal training day.

Is it somehow explainable through data or it is just a kind of 'you can' that makes you suffer a bit more than normal?

  • mmm,....interesting question, but I am not sure its quantifiable as it would be different for each person. I know what motivates me in races vs training, but that isn't necessarily what would do it for you.
    – JohnP
    Jan 18, 2019 at 15:30
  • @JohnP thanks! So my first and main question here would be on this: is the progress due to being in a race quantifiable or is it just a matter of adrenalin and self convincing to suffer a bit more?
    – fedorqui
    Jan 18, 2019 at 15:39
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    No and yes and yes and no. I think it's probably a great discussion/chat question, just not sure you can define a set of variables that is common to everyone. But you may get some great answers, so I'm not voting to close, we'll see what the community can produce. :)
    – JohnP
    Jan 18, 2019 at 15:42
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    Few thoughts. Runners will usually taper for a race, which they wont do for a training run. decrease training in the days before to ensure they are fresh. drafting is a much smaller effect than in cycling, but there is a small advantage in having someone run in front of you (and behind you) to move a body of air along for you. There are also believed to be psychological advantages: "i am gonna beat that guy in front of me!". Jan 19, 2019 at 14:00

2 Answers 2


As you're alluding to, there are many answers to this, but they can get vague and debatable. Let me give you a concrete one though.


There's a great runner's movie called Without Limits about Steve Prefontaine. This is the most relevant scene, but the theme is throughout the movie: https://www.youtube.com/watch?v=bLefVdWUzbE

When Pre was in high school, he didn't need to even consider drafting because he was so far ahead of everyone. But when he got to college and he can't just lap everybody, the whole element of running with a group becomes important.

Not too complicated from there. If you're in front of everybody, you're taking the brunt of the wind. If you're behind someone, you can conserve yourself, which you can't, or are at least very unlikely to, do in training.

Even in a recreational 5k, one is likely to do some drafting, even accidentally, which can give a boost compared to running by yourself in training.

I realize you may also be referring to a more general case, say, why do powerlifters lift more in competition than training, and you could get into tapering / peaking, but again it's not necessarily ironclad. After all, could someone peak and lift the same, but without the crowd around them? (Not many bother to even attempt that.) It gets rather subjective.

Hey, some do worse when the lights get brighter. Not just because of psychology. The Olympics are often not a good time for world records, because of all the heats one has to do to qualify, where fatigue becomes a factor. Then again, when you're Usain Bolt and that much faster than everyone, to where you can jog the prelims, and you clearly love the crowd, the Olympics might be perfect for you.

But drafting is physics.

  • 1
    Interesting quantification of the effect here: runnersworld.com/training/a20823445/…. Authors estimate drafting can save up to 80% of the energy expended overcoming drag, which is under 2% of the total at the OP's speed. A total energy savings of 1-2%, which could be just enough to push the OP under the 40-minute mark. Jan 30, 2019 at 13:58
  • Pre is one of my running idols. Good analysis on the effects of drafting, and the higher the speed (such as cycling), the higher the effect. Also with wind the effect is multiplied.
    – JohnP
    Jan 30, 2019 at 16:01

Another thing, alluded to by @brian-reddy above, is tapering.

  1. When you're training, you're not recovering completely from the previous run. This is because:
    1. You would only train once a week.
    2. There's value in training a little bit tired.
  2. When you're training you're not typically running as fast as you can very often.

But when there's a race, you taper before it. You run less (not the same as "don't run"), and some of what you do is train running fast. Like everything else, the more you do "run really fast" the better you get at it.

Most of my training year round is done well below my fastest speed. Maybe the occasional fartlek, but no sustained 5k, 10k, ... top speed runs. When I have a race coming up, about two months out I'll do a mile as fast as I can (and give myself more recovery time afterwards than usual). I'll swap out two miles of normal running for one that's fast every few days. Just before the race I'm not running that much, but what I am running is fast.

Good luck with whatever you end up doing.

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