This sprightly figure in tracksuit top and shorts looks neither to left nor right as he cleaves through the mayhem like a tracking camera on the set of Apocalypse Now. Vanity, perhaps, sets his schedule. And for all I know, the old boy may collapse in a puffing heap after he has rounded the corner. But I strongly doubt it.
This man represents, to me and I suspect many other mothers and fathers milling in the school zone, a daily rebuke.
Thought process one: I am not getting enough exercise. I am not getting any exercise. When was the last time I exercised? And yet look at this man, disciplined, trim, regular... what kind of a shambles will I be at his age?
Thought process two: What a telling contrast. As we middle classes unload our pampered offspring from the padded interiors of our Volvos, Audis and Renaults, here is a warning made flesh for our children. We are corrupting them with comfort. And unless we change, they will pay a heavy, an obese, price.
Such swirling feelings of guilt were given another stir this week by the emergence of a report pointing out how much healthier were the generation brought up in the austere, post-war years, when rationing denied them the range of empty calories now so readily available to the young (and old).
But for all the superiority of their diet, it was the superior level of exercise undertaken by the baby-boomers which was said to make the crucial difference.
As I write this, I am looking at another standing rebuke to my parenthood - a pair of football boots belonging to my seven-year-old son which he has not worn in earnest since they were purchased a month ago.
Unlike me at that age, he can't simply sling his boots over his shoulder and walk to the nearest park, put them on, play all day and wander back for tea. Responsible parents can't allow that sort of freedom to their children these days - or at least, they don't believe they can, which amounts to the same thing.
I can, I should - I do now - vow that I will accompany him to that park as soon as maybe and never mind the Christmas shopping. But the point is, it's always an effort all round. Exercise isn't a part of children's lives in the way it once was.
During the summer, a number of families from our children's school meet up for picnics in a large and ancient local forest. It's National Trust territory, naturally enough, with ice creams and toilets available beside the lake. But even in this environment, if my children go careering off beyond the nearest copse to play, I am uneasy. And pretty soon I will feel constrained to put down my tuna and lettuce sandwich, find all the relevant parties and lecture them about playing within suitable range.
The fear is not so much that they might injure themselves, or get lost or even fall in the lake. The fear is of other people who might wish to do them harm. It didn't used to be this way. It shouldn't be this way. But it is.
For the rising generation of the 1990s, supervised exercise within circumscribed areas is becoming the norm - playbarns, swimming pools, fenced-off recreation areas and, in time, gyms.
Passing through Birmingham city centre earlier this week, I glanced upwards at a crossroads and found my gaze being drawn to a gym overlooking the busy streets which offered its occupants an opportunity to see and be seen through wide windows. A black woman in a shocking pink leotard maintained a steady run on an unseen treadmill. To her left, pink knees rose and fell as others exercised in prone position, while on her other side, a woman in a yashmak conducted her own exercise regime at steady walking pace. It was an impressive tableau of multi-cultural harmony, a vision of the future of exercise in an increasingly urbanised society. And, yes, another rebuke.
There is nothing else for it. It's time for me to look out my trainers and tracksuit - last seen under a pile of newspapers in the front room - check the opening times of the local swimming pool and reset the controls for Planet Exercise. We'll just have to make up for all the hard work at Christmas.