To get an understanding of how player age impacts performances,
it’s important to first decide on a good metric to incapsulate performance in the first place.
In football, that’s not as straightforward as in other sports.
For a start, the games are more fluid and the roles on the pitch are highly specific.
Due to that positional variability, there’s not a single figure to explain performance
for every role and position on the pitch in the same currency.
Different metrics could be considered per position to get an overall understanding of
how things change from a stylistic point of view,
but metrics such as those don’t give a good indication of a player’s general effectiveness.
The solution, then, isn’t some fancy all-encompassing metric that tries to
look at a player’s true value on the pitch. No, the best stat to use here
is just plain, basic minutes played. There are several reasons for that.
For a start, part of the impact of ageing on players isn’t just that their abilities drop off,
but also that their bodies become less and less durable. It is a cliche, but the best ability is
availability, and that’s a big factor when it comes to rating a player’s ability at any age.
Second, there is some implicit notion of a player’s quality captured in their minutes played.
Managers pick their teams for many different reasons — form, injuries, suspension, player
preference, tactics — but more often than not, they’ll want to play their best players to win a
game. The mere presence of a player on the pitch, therefore, says something about how good they are.
Finally, it’s also something that is accessible for the past few seasons in the Premier
League, and to calculate anything to do with peak ages and age curves, plenty of data is required.
So, in terms of minutes played, when do players look to peak? This chart—
inspired by the original work of Michael Caley — looks to answer that.
Both starts and substitute minutes are taken into account from Premier League matches over
the past decade, with the player ages as they were on August 1st of every season. Players
are split into one of seven different positional groups depending on where they featured in games.
The graphic maps all ages between 18 and 38 years old, broken down by position.
The colours on each scale denote the share of the total minutes
played for each age, over the past 10 Premier League seasons.
The redder that the age is shaded, the higher the share of total minutes played
for that age within their position.
Goalkeepers are the oldest positional group,
with the latest peak age and plenty of players playing well into their early 30s too,
as denoted by the lighter shading. It’s a position in which fewer opportunities are
given to younger players, and experience seems to be prioritised over younger, fitter goalkeepers.
Centre-backs also peak relatively late, at around 27, with plenty of players featuring heavily in
their late 20s and early 30s. As with goalkeepers, the nature of the role isn’t as comparatively
physically demanding in terms of needing to hit top speeds or cover great distances. However,
a player’s ability to read the game will improve with time, sometimes making up for the speed lost.
Full-backs peak far younger, with the majority of their minutes coming at 25.
What’s interesting is how the increasingly demanding nature of the role has impacted
the age curve at the position. Full-backs are now asked to get up and down the pitch
far more. They also need to be technically gifted and have a high level of tactical understanding.
For that reason, they are likely to be one of the most athletic players on the pitch,
which explains why fewer minutes are going to players in their late-20s.
As in central midfield. The most common age for a player in this position is around 25,
with a fairly large spread of players playing consistently between the ages of 24 and 30.
Wingers and wide attackers hit their peak even earlier, reaching the height of their powers
around 26. It makes sense, then, that they see plenty of minutes in their early 20s and fall out
of the game or are required to change position to stay in it by the time they hit their 30s.
No.10s are the least common playing position, as fewer teams are using a single playmaker.
There’s a peak for them at age 26, but theirs is a position to take with a pinch of salt.
Due to their relative scarcity in the modern game, there’s something of a sample bias here,
with just 1,098 players in the last decade playing in that position in a single season
and there only being 55 player records with 1,000 minutes or more. There’s an early spike
around 22 years old in the data thanks to this, with Ross Barkley, Christian Eriksen, Oscar and
Dele Alli to name just a few all featuring heavily in the Premier League at that age.
Finally, strikers seem to have the most well-defined ageing pattern of all the
positions. They rise to prominence in their early 20s and peak around 27, with only the proper
outliers able to sustain themselves in the game past their early 30s. Similarly to centre-backs,
their feeling of the game increases over time, but they are limited more by physical drop-off.
Taking all of this into account means that a rough band of “peak ages” can be formed
for each positional group. This is calculated by taking the peak year and adding and subtracting
a year from either side. For goalkeepers, any player aged between 27 and 29 will be considered
in their peak. For full-backs and central midfielders, that’s any player aged 24 to 26.