Even at 82 years of age, there are no faltering notes in Tom McNab's silky, authoritative baritone. No void in his astonishing memory. No abating his ravenous thirst for sport, literature and fulfilment.
He's not long completed his morning slog on the tennis court - no double faults today, he's pleased to announce - and will spend the afternoon sculpting his latest novel.
A Scottish champion triple-jumper and Olympic coach who tutored Daley Thompson and Greg Rutherford, McNab honed the British bobsleigh squad, whipped England's then-amateur Rugby World Cup party of 1987 into shape on the track and crafted highly effective schools athletics award schemes in a career spanning six decades.
Lighting the flame
An extraordinary brain was first captivated by the feats of boys' comic strip hero William Wilson in the 1940s, kindling in McNab a lifelong obsession with sport fuelled by hour upon blissful hour of street football in north-east Glasgow.
What he may have lacked in God-given athleticism was ably compensated with raging passion.
Though he'd "never even won a school heat", at 17, a teacher invited him to compete in the Scottish Schools Championships - an offer he later realised was a convenient way for the older man to visit his girlfriend in Edinburgh.
"I didn't get anywhere until it came to the triple jump - the first jump I made broke the Scottish record immediately," he laughs. "It wasn't a great record in those days.
"By the end of the year, I was fourth in Britain. I wasn't even fourth in my bloody school!"
The coaching pathway
On completing his RAF National Service in 1954, Flying Officer McNab returned to the track at Shettleston Harriers, always itching to enhance himself, his colleagues and his club.
He joined the Harriers committee and convinced his secretary to invest in pole-vaulting equipment - his first inadvertent step on the coaching ladder.
"I looked across the track and saw this big skinny guy, Norrie Foster," he recalls. "The club secretary said, 'Oh no, no, you can't have him. He's a very good runner'.
"I brought him over, swung him over the bar holding the pole myself - he loved that. He asked if he could do it again next week.
"That year, I saw him every Sunday; he won the Scottish Schools title. A couple of years later, he was the British junior champion.
"I didn't realise I was coaching, but I was. It was just sheer chance looking across the track - if I'd found somebody else, I don't know whether I could have done it!"
Pleasure through achievement
Sixty years on, McNab still harbours great interest in bettering young athletes.
"The danger at school is that we tend to coach the best and leave the rest," he asserts.
"A lot of the stuff that happens at that early age is too fun-based and not achievement-based. You should get the pleasure through achievement. You don't get the achievement through fun.
"It's about learning; children are still hungry animals."
Adamant he could enter his local supermarket, pluck an average shopper from the aisles and teach them the fundamentals of the shot-put in a solitary minute, McNab's anguish at the over-complication of coaching is intense.
"We get seduced by the idea that foreigners must know more than we do," he says.
"You're looking at characters who have been given a constant flow of top-level college athletes; they've never had to deal with people like Norrie!
"They produce all sorts of complex training methods and theories to justify what they're getting paid.
"In fact, the job of the coach is to make things simple. Making it simple is not easy to sell.
"I believe there's a lot of talent in Scotland; we've got to deploy the coaching talent much more effectively to get it to the physical talent as frequently as we can."
Chariots of Fire
The convergence of creative flair and practical nous led to McNab being appointed technical director in the production of smash-hit film Chariots of Fire, showcasing the exploits of God-fearing Scot and sprinter extraordinaire Eric Liddell and his team-mates in the Olympic Games of 1924.
McNab was duly charged with selecting and training the actors while ensuring the picture's athletic authenticity.
The preparation, however, was not without its mishaps.
"The actors always trained in warm-up shoes because I was afraid they would hurt themselves in spikes," McNab recalls.
"Eventually, I bought this big box of spikes. The guys had never worn spikes before in their lives and they thought they were just fantastic.
"I had my three-year-old daughter with me and I said, 'don't put them on, we'll use them next time, don't touch them,' as I'm tying her laces.
"The next thing, I hear this big scream. Nigel Havers has run into the hurdle, tripped over his spikes and hit the ground.
"Ben Cross took him to hospital, but I didn't realise he had broken his wrist. And, if you look at Nigel's wrist now, it's like something from a horror movie - it never got put together again.
"But he was a super guy, Nigel, wonderful to work with and he learned the hurdles quite well."
Alongside six weekly hours of tennis, McNab threw the hammer and played rugby with great gusto if not talent - "I did for rugby what Quasimodo did for coathangers" - well into his sixties, once taking the field alongside Sean Connery's sons.
The body may be wearying - if only a little - with the inexorable passage of time, but the mind remains as agile and scrupulous as ever.
"Sir Harry Lauder used to sing, 'Keep right on 'til the end of the road, keep right on 'til the end'." he says.
"I'll be stopped eventually by my health, by death itself. I've got less energy than I did before. But I just keep going."
It's the pen before the stopwatch that grips him these days as a prosperous author and playwright.
And, for this trailblazing octogenarian, a chapter or two is still to be scribed before he exits stage left.