What Your Marathon Splits Say About Your Race — Reading the Pace Colouring

What the colours are

The line is darker where you were slower and brighter where you were faster, on a scale set by your own race, not by anyone else's. A 3:00 marathon and a 5:00 marathon both use the full range. Under the map, the splits strip shows each 5K (or mile) as a bar, and the figures beside the time show the average pace, the climb and the negative split: the second half minus the first, so a minus sign means you sped up.

The four shapes

The even race. The line is one colour from start to finish, give or take the hills, and the splits strip is level. It is the rarest shape and the one people frame twice.

The negative split. Brighter in the second half than the first. A held-back first 10K, a settled middle, a lift from 30K. The figure beside the time is negative. Berlin and Valencia produce more of these than any other course we draw.

The fade. Bright through halfway, then the line darkens from about 32K and stays dark. The splits strip steps down. It is the most common shape on the wall, and the honest one: most marathons are run this way, and the print does not hide it.

The blow-up. Bright, then a sudden dark stretch, then a bit of colour back for the last kilometre. A wall, a cramp, a stop at a toilet. The print shows the stop as a dark band, not as a gap, because the clock did not stop.

Where the courses leave their mark

Every course writes something on the colouring. London darkens at the Isle of Dogs and brightens on the Embankment. Berlin fades along the Kurfürstendamm. Boston is bright for 16 miles, dark up Heartbreak Hill, then bright again down to Boylston Street. Dublin darkens at Milltown. New York changes colour at every bridge. The race pages describe each one; the print draws yours.

Reading your own

• The first 5K is dark. Normal: the start is crowded. If it stays dark until 10K, you were stuck in the wrong pen.
• A single dark bar in the strip. Usually a hill, a drinks station, or the toilet; check the elevation strip under it.
• Miles brighter than kilometres. They are the same race; a mile split smooths the noise a little, so it looks calmer.
• The last bar is bright. Nearly everyone finds something at 41K. It is the one bar that is always bright.