Like a Formula One driver, you should cover the minimum distance possible. "Take the racing line," says Lumley.
Think about how a racing car swings in to a bend from out wide to hit the apex before it drifts out again under acceleration. This is the fastest way for humans, too.
"Numerous studies have shown it's best to run at an even pace, or aim for a slight negative split, where the second half is faster than the first," says Lumley. "Metabolically, this is the most efficient way to run." It also means you have energy in reserve for a duel with a rival," he says.
"How to run properly is a contentious subject," says biomechanics expert Sturdy. "There is an efficient way to run, but there are infinite variations because of our different body shapes.
"You want to be travelling forward, not vertically, so I run in a pair of shorts with a heavy weight in the back pocket. That way I can feel if it's going up and down too much and correct it so I have a lower centre of gravity."
Refuelling has been banned in F1 - but not in triathlon. And you need to make your own pit stops as fast as possible.
"I use Clif Bar Shot Bloks, which are electrolyte jellies that dissolve in your mouth," says Sturdy. "I don't like too much water in my stomach, so will only take small sips, but I always have the jelly in my mouth - without chewing - even if I don't necessarily need it."
Your shoes are like F1 car tyres, and will affect your performance. "Experts may tell you different things, and it pays to experiment," says Sturdy. "I used to run in motion-control shoes because that's what all the experts told me I needed, but when I studied biomechanics I tried different things out for myself, and now I run in flats with no support."
"Make sure your shoes are as light as possible," says Sturdy. "Every few grams on the end of your leg can make a difference to how much energy you use."
Some other add-ons are crucial. "You need as much 'free' speed as possible," says Lumley. "Loose-fitting or wet clothing will weigh you down, so wear fitted, technical fabrics.
Wear sunglasses in summer, because they help relax your facial muscles - squinting can tense your face, which spreads to your neck and shoulders. Wear a hat with an elasticated rim so it doesn't pinch.
And beware jewellery - watches and rings can vibrate through your pedals and distract you. That can get a bit wearing in a long race."
The individual gains may be small but if you add them up, you'll find that a new PB is on the cards the next time you toe the line, even if you don't add go-faster stripes to your kit.