This is the heart-stopping moment a young man sitting under gym equipment playing on his phone gets struck by a 40-kilo barbell that fell and almost killed him.

CCTV cameras captured the moment the heavy weights suddenly dropped onto the young man's shoulders at a gym in Chengdu, China, on December 30.

The man told staff he was playing on his phone while resting between sets. Suddenly, the 40-kilogramme barbell he had been using which sat above his head fell on him.

Shocked by the strike, he dropped on his knees and turned around to find the barbell had struck him after he had apparently failed to secure it properly.

Despite the obvious pain it caused, he expressed relief that the weights did not hit his head or the consequences could have been fatal.

He later said: 'I was doing the shoulder press with a one-minute rest between sets, that's all.

'I wasn't hogging the equipment; there weren't many people that day. I sat down for that one minute.

'My phone saved me; I don't usually play with my phone. It could have hit my head or spine.

'In the future, I'll stand up during breaks. I've realised my mistake.'