Pacing is budgeting — and what you are budgeting against changes with every distance.
It was a warm and slightly muggy Birmingham August evening at the 2026 European Athletics Championship, hardly ideal conditions for a 10,000m final. The Italian Nadia Battocletti had already run 9,800 metres and was bunched up with a few other athletes in the last lap, when she decided to unleash a spectacular final 200m of 28.2 seconds that left her fellow runners in the dust, and the audience, stunned. Earlier in the Championship, Audrey Werro, the 800m champion who has brought a whole new level of performance to that event, ran her final 200m in 29.1 seconds. Pause, and say that again: a woman who had just run 9,800 metres ran her last lap faster than a generational talent — the 800m champion.
It is the kind of statistic that makes you wonder whether the laws of running have briefly taken a holiday. Instead, it shows that how you pace a race matters, at every level of the sport.
We use the word constantly in almost every running conversation. Pace yourself. Don’t go out too fast. Negative split. But what exactly are we pacing?
Sports scientist Ross Tucker has a useful analogy: pacing is to physiology and performance what budgeting is to finance. You have finite resources (money) for a specific time-period (say, a month) and must decide how much to spend, when, and how, such that you spend your last rupee of the monthly budget exactly at 5 pm on the last working day of the month.
In the physiological sense, when it comes to exercise (running), we have to manage budgets around both ‘depletion’ and ‘accumulation’. We deplete carbohydrate and rapidly available energy stores (especially in longer endurance events like the 10K/HM/marathon). We accumulate metabolites that impair muscle function (especially in shorter events like the 400/800m), and over longer efforts, also accumulate heat — increases core body temperature — and mechanical damage.
Pacing is about continuously regulating the intensity to keep these competing processes of accumulation and/or depletion within tolerable limits, for peak performance.
The balance changes with the event. And that is where pacing gets interesting.
An 800m runner has little reason to worry about running out of glycogen in two minutes. The pressing problem is rapid accumulation of fatigue-related metabolites and the resulting deterioration in muscular performance. Go out recklessly hard and your legs can eventually stop obeying instructions and just seize up.
The marathon presents a different calculation. Glycogen depletion, heat, muscular fatigue and fuelling become increasingly important. The price of an overambitious opening 10K may only become apparent 25 Kms later. For both these types of endeavour, the definition of pacing stays constant; what changes is what you are pacing against.
| Event | Major constraints | Typical pacing shape |
|---|---|---|
| 800m | Rapid metabolite accumulation; neuromuscular fatigue | Fast first lap; slower second |
| 1500m | High-intensity accumulation; energy demand; tactics | Fast opening; steadier middle; kick |
| 5K / 10K | Metabolic and thermal stress | Relatively even; late acceleration |
| Half marathon | Sustained high intensity; heat; fuel availability | Even; sometimes slight negative split |
| Marathon | Glycogen; heat; muscle damage; fuelling | Even to slightly negative, conditions permitting |
In an 800m, elite runners typically spend aggressively early, accepting that the second lap will be slower. All the world’s best 800m runners run positive splits, in contrast to longer events. The key challenge for elites in this event is to exploit that early speed without creating so much physiological disturbance (accumulation) that the closing straight (last 200-100m) becomes a losing negotiation with your quadriceps.
The marathoner must protect resources for hours. Running a few seconds per kilometre too fast early can carry a cost far greater (depletion) than the time gained. On a flat course in favourable conditions, very even pacing in HM/marathons, sometimes with a slight negative split, is generally a sound strategy.
When it comes to the 5K/10K, an analysis of world beating performances across decades shows how elite pacing has flattened over successive generations. Earlier records often combined fast openings, slower middle kilometres and big finishing kicks. More recent record attempts show remarkably consistent splits with relatively modest end-spurts. As athletes approach their physiological limits, there is less room for inefficient expenditure.
A championship 1500m or 10K on a track, is a different proposition from a paced record attempt. Athletes must cover surges, bide their time, avoid being boxed in and judge when to launch a final kick (like Battocletti). The quickest route to the finish may not produce the fastest possible finishing time.
For most recreational runners chasing a 10K, HM or marathon PB, the race is essentially a time trial with several thousand other people conducting their own time trials nearby. For us, physiological pacing (optimally managing depletion) should usually outweigh tactics, i.e. trying to mimic or run someone else’s race.
Heat and humidity raise thermal stress. Altitude reduces oxygen availability. Hills and headwinds make familiar pace more expensive. The same number on the watch can demand very different effort on different days.
Even pacing on a flat track often resembles even speed. On a hilly course, chasing the same kilometre split uphill may be an excellent way to sabotage the kilometres that follow. Ease the pace uphill, manage downhill muscle loading and use perceived effort alongside your watch. The goal is to control the physiological cost, rather than keep the GPS display aesthetically pleasing.
| Distance | Race-day approach |
|---|---|
| 800m | Commit early, but avoid an opening 200m so aggressive that the second lap collapses. |
| 5K | Control the opening kilometre, settle quickly and build effort into the final kilometre. |
| 10K | Aim for very even splits; keep the first kilometre disciplined and finish decisively. |
| Half marathon | Resist early adrenaline, settle into sustainable effort and build over the final 5K. |
| Marathon | Avoid banking time. Start controlled, fuel consistently and preserve the option to finish strongly. |
None of this is easy to execute. When we looked at the splits from the Tata Mumbai Marathon 2026, fewer than four in every hundred marathon finishers ran the second half faster than the first, and the proportion fell steadily through the slower brackets.
Pacing is very much an acquired skill, and like most running skills, it improves with practice. Every tempo run, interval session and race teaches us something about the relationship between pace, effort and fatigue. Over time, we learn to recognise the difference between an ambitious opening kilometre and an expensive one, and between discomfort we can sustain and discomfort that will eventually send us the bill.
Leverage your training to intelligently set your goal (budget). Ideal goal time should be a stretch, but not unrealistic relative to your current fitness.
On race day, manage depletion/accumulation (spend) wisely.
As recreational runners, we spend considerable time improving our aerobic engines, optimising training zones, and refining fuel strategies. Yet, all that is of limited use if we manage/spend it unwisely on race day.
Finding the Next Percent can come from developing that same judgement: knowing when to hold back, when to settle into a rhythm and when to commit whatever remains. This is true pacing – a finely honed skill that no GPS watch can entirely replace.
Race-day pacing checklist
Before you start
The first quarter
The middle
The last quarter
Afterwards
If the course is not flat — and in India it rarely is — a single goal pace is not a good idea. Our pacing chart on RunStrong takes a race route or your own GPX file and gives you elevation-adjusted splits, kilometre by kilometre.
RunStrong Get elevation-adjusted splits for your next race Open the Pacing Chart →[Cover image credit — Sanchit Agarwal.]
Related in this column: Into Thin Air — what altitude teaches every runner and The Fuel Switch — metabolic flexibility for endurance runners.
