The priming effect: how a hard warm-up can help performance


As of September 2017, new Sweat Science columns are being published at Check out my bestselling new book on the science of endurance, ENDURE: Mind, Body, and the Curiously Elastic Limits of Human Performance, published in February 2018 with a foreword by Malcolm Gladwell.

- Alex Hutchinson (@sweatscience)


Most people who do hard interval sessions will have noticed this mystery: why does the second or third interval usually feel easier than the first one? I always figured it had to do with “getting into the rhythm” or something along those lines. Whatever the reason, Pete Sherry — my main training partner for 2002-2004 — and I eventually decided that we’d run 2x400m in ~72 sec a few minutes before every workout, in the hopes of making the first interval feel easier. Our impression was that it worked, and we started doing it before races too.

It turns out there’s plenty of physiology behind this. If you suddenly start running at a hard pace, with no warm-up, it takes a while before your body can adjust to start delivering oxygen to your muscles at its maximum possible rate. That’s one of the reasons VO2max tests take 10-12 minutes, rather than simply involving a short, all-out sprint. It takes time for the blood flow to your muscles to increase, and for the enzymes that extract oxygen from the blood and oxidize fuel to ramp up their activity levels. A good warm-up gets this ramp-up process over with, allowing your body up to deliver more oxygen to muscles right from the start of the workout or race, and reducing the temporary oxygen debt.

Still, most people warm up with gentle jogging, flexibility drills, and some short sprints. But how about including a six-minute “hard” effort (above lactate threshold but below VO2max pace), about ten minutes before the start of your race or workout? Would that “prime” your oxygen kinetics even more? The challenge is as follows: a sustained burst of hard exercise (above threshold) definitely improves how quickly your body can process oxygen once the actual race starts; this effect can last for a half-hour or more. If you exercise too hard, on the other hand, you deplete your anaerobic energy stores (phosphocreatine), and metabolites build up in your muscles that may slow you down. Numerous experiments over the past decade have found conflicting results: depending on the precise details of the duration, intensity and recovery time following the “priming” burst, performance either increases, decreases, or stays the same.

A new cycling study just posted online at Medicine & Science in Sports & Exercise, from Mark Burnley’s group at Aberystwyth, adds some more data on finding the right balance. They used a six-minute priming bout, 10 minutes before the “race” — a formula that other studies have found to be effective. For intensity, they compared “heavy” (about 25% of the way between threshold and VO2max power) and “severe” (about 63%) priming bouts. The findings: “heavy” priming boosted oxygen kinetics and significantly increased time-to-exhaustion in tests ranging from ~2-10 minutes. “Severe” priming also boosted oxygen kinetics, but didn’t increase time-to-exhaustion, suggesting that the downside of depleted anaerobic reserves outweighed the benefits of more aerobic energy available early in the test.

So what does this mean in practical terms? It’s hard to know how generalizable this protocol is, but I’d say it’s worth experimenting with some sort of extended surge ~10 minutes before the end of your warm-up. If you’re doing a six-minute effort, it looks like you should aim just above your threshold. I know quite a few runners who have incorporated similar but shorter surges of ~1-2 minutes into their warm-up routine. There may be a good argument for runners to stick to shorter surges, since the impact of leg-pounding is a bigger factor than it is in cycling. In that case, you may be able to get away with a higher intensity. But so far I don’t think the research has answered that question — for now, it’s trial and error.

10 Replies to “The priming effect: how a hard warm-up can help performance”

  1. Thanks for sharing this!
    I always feel that I play better soccer games when I ride my bike hard to the field – now I’ll just have to keep doing this!

  2. My first 2 miles when running always feel the hardest. I think I will try warming up in future before racing.

  3. Very interesting. It makes sense but it also seems very difficult to control the density of the exercise required to achieve that ‘optimal state’.

    Even harder when we talk about team sports like soccer, basketball, etc where we have different people with different physiology. But people from individual sports should definitely look after this, it may be very useful.

    Great post.

    Telmo Abreu Silva

  4. Interesting read. I tend to do very little warm up before a race – I’m always afraid of wasting precious energy. However, I usually feel awful for the first couple miles. If someone were doing a long distance race, say a marathon, would you think the extra few minutes of intense warm up would benefit ones overall time? Or is that just energy you are taking out of the bank?

  5. Interesting. Once again, there seems to be a disconnect between the available scientific evidence and practice. Are the pros just too hidebound, or are they looking at different science? A pro preparing for a TT, even a short prologue that takes 8-10 minutes to complete, spends on the order of an hour warming up. That can’t all be at super-threshold intensity, though of course there could be some brief periods of high intensity buried in that hour.

    On the other hand, I’ve never observed a pro warming up for a mass-start stage (though of course, the neutral roll-out means they are never completely cold when the flag goes down.) Yet I had a pro tell me just this weekend that after the first hard effort that drives up your heart rate, you are good for the race …

  6. Thanks for the comments, folks.

    @Stephen: I don’t think this is something you’d want to apply in a marathon or comparable longer race. For one thing, the pace you’re starting at is much slower — slower than threshold pace (unless you screw up!) — so the problem of incurring an initial oxygen debt is much less likely to be a factor. The study above looked at efforts between 2 and 10 minutes. My guess is it might be relevant for races below threshold, i.e. shorter than about half-marathon, but probably not for anything longer. The elite marathoners I’ve spoken to tend to do a very minimal warm-up: 5-10 minutes of jogging.

    @Phil: Incorporating this research wouldn’t mean than the warm-up should take less than an hour, and the vast majority of that should of course be below threshold. They’re suggesting adding an additional component (for cyclists, a six-minute hard effort that finishes about 10 minutes before race start) to the existing warm-up routines. It’s an add-on, not a replacement.

    In running, I know many runners have incorporated this type of idea for years. (Someone on Twitter pointed out that Jack Daniels has long advocated 2×400 at I-pace or 800-1000m at T-pace in his books.) I’d be hugely surprised if some top cyclists aren’t doing similar things. But if they’re not, it doesn’t mean they’re unaware of the research — as I mentioned in the blog, studies over the past decade have produced conflicting results depending on the precise details of the protocol. It wouldn’t be irrational to avoid doing something that seems to have as much chance of hurting you as of helping you. (Though personally, it seems like it would be worth experimenting with it in training at least.)

    One other note: you don’t always have control of your warm-up circumstances in competition. For the average runner at big road races, you may need to crowd into your pen 20 or 30 minutes before the start. For elites at big track championships, you’re often kept in a tiny holding room from ~30-40 minutes before race time until just a few minutes before the start, and only permitted to do a few strides just before the start. So there’s some rationale for not getting too anal about the precise choreography of your warm-up.

  7. tried it for the first time… resulting in a huge PR.
    If it was the believe in it or the addition to the warming up itself (or maybe something else), I already concluded that I keep believing in it.

    Never ran so easily, and without those terrible first 5-8 minutes,

Comments are closed.