Why pacing wisdom is repeated far more often than it is examined

The rule and its hidden assumptions

The common advice is that effort should be distributed evenly, since surges cost more energy than they return and leave a deficit later. That reasoning holds when the objective is the fastest possible time and when the athlete is racing the clock rather than other people. It holds less well when the objective is to win, because winning may require responding to moves regardless of their metabolic cost.

The rule therefore encodes an assumption about the goal, and it is delivered as though it encoded a fact about physiology. Athletes who follow it in tactical races are optimising for something they were not trying to achieve.

Event duration changes the answer

In very short events the energy systems involved make a fast start close to mandatory, and any attempt at even distribution is simply slow. In long events the accumulated cost of variability grows, so the argument for evenness becomes stronger as the distance increases. Between those extremes lies a range where the correct answer depends on the individual balance of aerobic and anaerobic capacity.

A single rule applied across that range will be right at one end and wrong at the other, which is exactly what a heuristic does. Presenting it as universal removes the information a coach would need to know when it applies.

Individual physiology resists the generalisation

Athletes differ in how quickly they accumulate and clear metabolic byproducts, which changes how costly a surge is for each of them. An athlete with a large anaerobic capacity can afford variability that would ruin the race of an athlete without it. Prescribing a distribution without reference to that difference assumes a uniformity that does not exist in any competitive field.

Testing an individual response is possible in a laboratory and requires equipment that most athletes never encounter. So the rule persists partly because the information needed to improve on it is expensive to obtain.

The evidence problem in racing

Establishing the best distribution would require the same athlete running the same race repeatedly under different strategies, which never happens. Comparisons across athletes confound strategy with ability, since faster athletes may adopt different distributions for reasons unrelated to optimality. Retrospective analysis of successful races selects on the outcome and therefore reports the strategies of whoever happened to win.

Those strategies may have been suboptimal for the winner and were merely less suboptimal than everyone else on the day. None of the available evidence has the structure needed to identify an optimum rather than to describe a distribution of attempts.

What survives scrutiny

The mechanism that surges are metabolically expensive is well founded and is enough to justify caution about unnecessary variation. The step to a prescribed distribution requires an objective, an event duration and a physiology, and the rule states none of them. A coach who names all three is giving advice that could be wrong, which makes it worth considerably more than the general version.

Runners applying pacing rules to their own training should be aware that the guidance was assembled for a different purpose than theirs. The general rule is a reasonable default and a poor substitute for knowing which race is being run. Defaults exist because deciding afresh each time is expensive, and that is a practical justification rather than a physiological one.