Holding a high line asks the wrong player to sprint

The physical bill for an aggressive defensive line is paid by centre backs whose bodies are least suited to paying it.

A centre back is selected, developed and conditioned for something other than a forty-metre turn and chase. He is usually big. He is usually strong in the air. He is frequently the slowest accelerator in the back four, and a high line asks him, several times a match, to do the one thing he is worst at, under maximum urgency, with a striker who has a running start.

That is the physical cost nobody puts in the tactical diagram. The turn is the dangerous part. Reversing direction from a standing or backpedalling position and reaching top speed within a few strides loads the hamstring near its limit, and doing it while twisting to track a runner is worse. The literature on sprinting injuries is not ambiguous about this, whatever the specific numbers.

So when a side plays a very high line and its centre backs keep missing weeks, the two facts are related and clubs rarely say so. It gets attributed to age, or to a poor pre-season, or to bad luck. Sometimes it is. Often it is a tactical instruction being converted into a medical outcome over the course of a season.

I would not abandon the high line. It is too valuable; compressing the pitch is how you stop a team playing through you, and dropping deep concedes territory that you then have to win back with even more running. The trade is real and mostly favourable.

What I would do is treat sprint exposure as a selection criterion rather than an afterthought. If your system requires recovery sprints from the last line, then recruit defenders who can produce them repeatedly, not defenders who can produce one impressive one. Those are different qualities and scouts conflate them constantly.

The other lever is the midfielder in front. A holding player who screens the ball well reduces the number of times the line has to be tested at all, because the pass over the top is only available if the passer is allowed to look up. Buying a good screening midfielder is, in a real sense, an injury prevention measure for your centre backs. It is never described that way in a transfer announcement.

Systems have physical consequences. We just tend to bill them to the wrong department.