Threshold work has quietly eaten the middle of the training week

A session designed to be repeatable has spread until nothing in a distance runner's week is truly hard or truly easy.

Somewhere in the last fifteen years the tempo run stopped being one session and became the default setting for everything that was not a jog.

The appeal is obvious. Threshold work is productive, it drives real adaptation in the aerobic machinery, and it does not wreck the athlete, so it can be repeated two or three times a week without the recovery cost of true interval work. Coaches noticed. Athletes noticed that it feels like proper training while leaving them able to walk on Tuesday. And so the volume of it crept upward until it filled the space where both the very hard and the very easy sessions used to live.

The cost is at both ends. At the top, the athlete loses the ability to produce and tolerate real intensity, because nothing in the week ever asks for it. At the bottom, the easy runs are not easy any more. They drift up to a pace that feels comfortable in isolation but sits well above where genuine recovery happens, and the athlete arrives at the next quality session already carrying something.

What you end up with is a week of medium. Every run within a fairly narrow band. It produces a runner who is impressively consistent in training and disappointing on race day, because racing is an intensity that they have not visited since last summer.

I am aware this argument gets used to justify daily suffering, and that is not what I am saying. The polarised approach, whatever you think of the label, is mostly an argument for making the easy days properly easy. That is the harder discipline. Slowing down feels like doing less and most athletes have no appetite for it, which is why the middle keeps expanding.

There is a decent objection: for a runner with limited weekly hours, threshold work is the highest return per minute available, and polarising a five hour week may just mean wasting three of those hours going slowly. I think that is right, and it means the argument is really about volume rather than principle.

But if you have the hours and your week still looks like one pace repeated six times, you have not built a training plan. You have built a habit, and it will hold at exactly the level it has already reached.