If there's no substitute for experience, then coach Arch Jelley (pictured above with John Walker) is irreplaceable. At 91 years old, he's still hitting the track, stopwatch in hand, hoping to guide his latest protégé Hamish Carson to the Commonwealth Games.

By 1939, Arch Jelley of New Zealand was both a senior gymnastics and featherweight boxing champion. In 1976, he coached countryman John Walker to Olympic 1500m gold. Before he 'retired' in 1987, he was a school principal.

As a runner, he came fourth at the New Zealand cross-country champs. As a gunner, he served on HMS Bermuda during the Second World War. More recently, he devised a completely new method of playing the card game bridge.

Despite all this, he still finds the time and energy to help an athlete 66 years his junior achieve his dream. We were lucky enough to meet him.

Arch, why are you still involved in athletics?

"I had retired from athletics in 2000. I had been president of the Mt Albert Bridge Club in Auckland, and I’d got interested in bowls. Then about five years later, I got a phone call from this lady, Julie, the mother of Hamish Carson, looking for a coach for her son.

"She said he wanted a coach who wasn’t too autocratic, but could also explain why he was doing the sessions. The phone call was a big surprise, but I agreed."

Do you still join in Hamish’s warm-down sessions?

"Not much. My running these days is restricted to around five minutes on the treadmill. I do run up the stairs [to their third floor apartment] but as my wife Jean says, 'it is only to show off'."

How have you retained your enthusiasm for athletics?

"I use the same principles I applied in teaching for many years. I try to be very positive and make sure we always have a lot of fun. It is important runners enjoy it. Otherwise it is hopeless."

When did you first get involved in running?

"I wasn’t a runner at school. I was very small and did a wee bit of boxing and gymnastics. It was only when I came back to New Zealand from the Second World War that I got into running. I was aged about 23 at the time."

Were you any good?

"In those days I didn’t do too much training, but I was a very consistent runner. In 1948 I finished fourth at the New Zealand national cross country championships. I was always very good at organising people. Back then I organised what was called ‘locality training’ – where we’d get the guys to train in different parts of the city [of Dunedin]."

@HamishCarson: The master at work #ArchJelley #Coach

So how did the coaching start?

"I was always interested in advising and coaching when I was running. I was fascinated by a guy called Arthur Newton, who was an ultra marathon runner from England. His big thing was, if you’ve got the speed, all you need is to increase your strength. I’d also heard about [Emil] Zatopek, who was doing huge mileage: about 100 miles per week.

"We also heard about this crazy guy called Arthur Lydiard [Kiwi endurance coaching legend]. Shortly after I moved up to Auckland in 1959, I had a conversation with Arthur. Funnily enough, we never discussed running or coaching, but I thought to myself: ‘if Arthur can do it, I could probably do it, too’.

"I could see the runners he was coaching were running really well on about 100 miles a week. I could see Arthur’s principles were very good. I started coaching in earnest in 1959."

How would describe your coaching style?

"I took on board a lot of Arthur’s principles but then brought on board a few ideas of my own. For example, if you are a genuinely fast runner like David Rudisha, there’s no way you are going to get him to run 100 miles a week.

"I don’t know what his training programme is, but I doubt it is much more than 60 miles. You have to look at the individual athletes, and decide what’s best for them. Some athletes can run 130-140 miles a week but if I had put John Walker on that regime, it would be suicidal."

Was coaching John Walker to Montreal 1976 Olympic 1500m gold your career highlight?

"I would say so. John also broke world records for the mile and 2000m [which lasted ten years], but world records come and go. The Olympic title remains.

"He only just won the final. Before the end of the race, he held his hands up in triumph, but of course when you do that you decelerate. He crossed the line winning gold, looking like he was carrying an invisible watermelon.

"I got an inquiry from an American guy, saying that he had heard that John Walker had had a sore knee but he had got rid of it. He then asked me where he could buy a tube of ‘Arch Jelley’. I’m being serious!"

What is the art to being a good coach?

"It is an advantage to have been a runner, because it allows you to empathise. You also should be positive - the athlete is doing what the coach wants, so if something doesn’t work out it is the coach’s responsibility.

"I applied the same principles as a teacher in that I treat everyone as an individual. When I look back I could have done certain things better, but I think that is true of most coach-athlete relationships."