IF anyone needed any reminder that marathon running is a brutal sport, the Gold Coast Commonwealth Games men's race rammed it home.

The images of race leader Callum Hawkins slowly falling apart as his body broke down within two kilometres of the finish line was heartbreaking.

All distance runners talk about the wall. They spend their careers trying to avoid it or at best learn how to deal with it when it inevitably strikes in a race.

It happened almost in the blink of an eye for Hawkins.

He'd been in the lead for 20 kilometres and had courageously sped away from the rest of the field opening up a two-minute later by midway.

The Scottish flags were getting unfurled at the finish line, such was the commanding way he'd run the race and 

given his vicinity to the finish line.

But then there were a couple of wonky strides. Then he threw his hat off. Then he brushed a barrier.

Suddenly he was in serious trouble. More barriers were hit and then he crashed to the gutter.  

Somehow Hawkins got up and wobbled another hundred metres up the road before his body gave away completely.

The sight of him lying on the road but still trying to get up was horrifying and eventually medical staff intervened as genuine concerns for his health spread through the crowd.

Australia's Michael Shelley was the beneficiary of the bizarre turn of events and he was overcome with emotion when he crossed the line to win his second Commonwealth title.

He'd also pushed himself to breaking point but he had one major advantage over Hawkins - he was a local boy who knew all about the Gold Coast's heat and humidity.

The race started at 8.15am - 55 minutes after the women's race - which meant the runners copped the brunt of the early morning heat. Should they have started earlier?

That question can be debated but there are plenty of marathons run around the world in far more severe conditions.

It's part of the gig, training your body to deal with a combination of heat, humidity, dehydration and fatigue over 42.195km.

Unfortunately for Hawkins he didn't get the mix right and those distressing images will now go viral around the world.

And it will remind everyone that marathon running is a brutal sport.