The fifth substitute professionalised the bench instead of resting the stars

Expanded substitutions were sold as a workload measure, and the workload they moved landed on the players least prepared to absorb it.

Count the minutes of the eleven best players at any large club before and after the substitution rules loosened. The totals barely moved. What moved was the shape of the squad below them, and nobody argued that case at the time because the change was presented as a health measure and nobody wants to be against health.

Here is what actually happened. A manager with five changes does not use them to take his best forward off at sixty minutes. He uses them to fix a game he is losing, to close one he is winning, and to get three fresh legs into a midfield that has been chasing. The players who come on are the fourth to eighth choices, and their week now looks very strange indeed. Full training load from Monday to Friday, a bench place on Saturday, twenty-two minutes at maximum intensity from a cold start, then a midweek start because the manager wants the starters fresh.

That pattern is close to the worst thing you can do to a muscle. A substitute enters a match already being played at a tempo he has not been part of, with a warm-up that finished when the fourth official raised the board and a body that has been sitting in cool air for an hour. The first sprint arrives within ninety seconds of entering. If you set out to design a protocol that injures people, you would design that one.

The counter-argument is that squads are deeper now, and deeper squads spread the work. True at maybe eight clubs in Europe. Everywhere else the rule handed an advantage to whoever could afford the eighteenth best player in the country, and turned the bench from a set of specialists into a second shift. That is a competitive change dressed as a medical one, and I would rather we called it what it is.

The fix is unglamorous. Warm-ups for substitutes need to be structured and repeated, not left to the player's own judgement in front of a stand. Some clubs now run bench players through a full second warm-up around the hour mark whether they expect to play or not, on the grounds that the cost of the extra work is smaller than the cost of a cold entry.

They are right, and the fact that this is still considered innovative tells you how thin the thinking behind the rule change was.