Every question you need to ask about running stats

Running stats in football aren't always used well, here's how to think about them better.

The way that media uses running stats is the perfect mix of 'very appealing' and 'not publicly scrutinised' that makes some stats people antsy. The data is being scrutinised though, in research papers and, more secretively, inside clubs. One day we may have clear answers, but for now we can at least ask smart questions.

What type of running?

'Running' and 'distance covered' are actually pretty vague terms: does 'jogging' count as 'running'? Do you care about total distance or just the distance when players are really working for it?

There's some variation in the categories that get used, but generally things get broken down into: walking, jogging, running, high-intensity running, and sprinting.

(A bonus question: how much does each of these contribute to overall distance...?)

What is 'normal'?

How much is 'a lot'? How much is 'noticeably little'? How much is 'normal game-to-game variation'?

Is 'more' better?

It seems reasonable to assume but is also worthwhile questioning. The next few questions help show why...

Possession and score-line: difference-makers?

Do teams 'run' more when they don't have the ball (and vice versa)? Do they 'run' more when they're trailing a game (and vice versa)? How would this affect your interpretation of running data after a match?

If you want to ask another, even tougher, question: can you even separate the influence of the two of them? We often see teams that win a lot (and therefore lead in matches) are also teams which have a higher share of possession. So if teams who lead in matches/have more possession do run less (if they run less), is that a result of the possession share or the score-line?

Possession: difference-maker? Part Two

Covering more or less ground is one thing, but we've seen that 'running' has different categories. So do players do different types of running in and out of possession?

(Related, if a TV pundit is trying to make a point about a team not working hard enough defensively, should they ask for specific out-of-possession stats?)

Is style of play a factor?

This might also be linked to the possession share question, given that higher amounts of possession can come from a team's quality or a philosophical belief in keeping the ball.

I mean, the answer to this is surely 'yes'. You'd imagine that teams who look to frequently counter-attack at pace would have different physical requirements to those that don't. But how much?

How do player position and role affect things?

Different positions, different roles within a team, have different physical expectations. The question is what the differences are, and how big they are.

You don't usually get people comparing running stats of players who play in different positions. However, even comparisons for the same position might not work because of an individual's style of play (note: famous walker, Lionel Messi).

Do substitutes run more?

'Sub effects' is a term that stats Twitter of the 2010s coined, meaning stats of a player who often came on as a substitute and had high figures that might be boosted by being a sub. E.g. maybe they came on against tired defences and racked up dribbles, shots, or goals.

Similarly, do substitutes have a different running stat profile to players who start matches? Obviously they'd run less than if they'd played the full match, but is 30 minutes of a sub appearance the same as 30 minutes as a starter?

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Bonus questions

And finally, this wouldn't be Get Goalside without some even more abstract questions...

Can you control for team quality?

'Team quality' is a vague concept, but if two teams were coached to the same level and had the same technical ability, would physical output be the deciding factor? Even if it turns out that running more doesn't strongly correlate with being more successful, might it be a factor in teams outperforming their 'ability' levels?

Does the sequence matter?

If a player jogs for 5km and sprints for 500m, how much difference does it make what order they do this in? Is there significance - in effort levels or fitness/injury risk perhaps - in them doing the sprint in regular amounts at regular intervals compared to in one or two big blocks?

How many questions is too many questions?

At the end of the day you probably want to use the running stats for something. How granular and individualised can you slice the running data without it becoming too individualised? How broad can you keep things, in the quest of a meaningful sample size to compare to, without losing important specificity?

Suggested reading:

Some research papers that I particularly enjoyed reading recently

'Are current physical match performance metrics in elite soccer fit for purpose or is the adoption of an integrated approach needed?' (2018), Paul S. Bradley and Jack D. Ade

'Match-related physical performance in professional soccer: position or player specific?' (2021), Stefan Altmann, Leon Forcher, Ludwig Ruf, Adam Beavan, Timo Gross, Philipp Lussi, Alexander Woll, Sascha Härtel

'Is it worth the effort? Understanding and contextualising physical metrics in soccer' (2022), Sergio Llana, Borja Burriel, Pau Madrero, Javier Fernández

Less directly about physical metrics but provided the research for 'famous walker, Lionel Messi':
'Wide open spaces: A statistical technique for measuring space creation in soccer' (2018), Javier Fernández and Luke Bornn