The warm down is mostly a ritual, and I would keep it anyway

Jogging after a hard effort does almost nothing the body would not do by itself, which is not the same as doing nothing at all.

Twelve minutes of shuffling round the outside of the track with your spikes in your hand. Everyone does it. Almost nobody can tell you what it is for without saying the word flush.

The flushing story is that easy movement clears metabolic waste faster than sitting down. The first half of that is true and the second half barely matters. Blood lactate does come down more quickly with light activity, because working muscle consumes it. But it would clear on its own within half an hour either way, it was never the thing making you sore, and no controlled study has managed to show that the faster clearance produces better performance the following day. The soreness that arrives on Thursday came from the eccentric loading, and no amount of jogging on Tuesday evening touches it.

That should be the end of the practice. It is not, and I do not think it should be.

Between rounds is the one case where the physiology genuinely supports it. An athlete with a semi final ninety minutes after a heat has a real problem, and active recovery at low intensity does appear to leave people better placed for the second effort than lying down does. Whether that is lactate, blood flow, keeping the core temperature and the nervous system somewhere near ready, or simply not stiffening up, it works often enough that I would never tell a finalist to skip it.

The rest of the argument for the warm down is behavioural and I am comfortable saying so out loud. It is a boundary. It marks the point where the session ends and the day resumes. It gives a coach ten unstructured minutes beside an athlete who has just done something hard, which is when the useful conversations happen, not during the reps. It stops young athletes going from maximum effort to a car seat in ninety seconds.

Those are good reasons. They are not the reasons on the poster in the gym, and the gap between the two is why people who read one study decide the whole thing is a waste and stop.

Call it what it is. A cool down is a small piece of housekeeping with a modest between-rounds benefit and a large psychological one. Sell it that way and it survives the next paper.

Sell it as detoxification and it deserves everything it gets.