This is the moment a training pal of Arnold Schwarzenegger shows he is not going to let anyone muscle in on his title as the world's oldest bodybuilder.

Veteran muscleman Andrew Bostinto put his astonishing body on show at a National Gym Association championship in the USA on 10th May, months after he turned 100.

Jaw-dropping video footage from his performance in the Gator class of the contest in Deltona, Florida, shows Andrew stripped to his shorts in front of a cheering crowd.

As fans gasp in amazement he goes through a series of classic bodybuilding poses showing off his bulging biceps and obliques.

His impressive performance made him the oldest person ever to compete in a bodybuilding competition.

Andrew was one of Arnie's early mentors when they trained together at then-original Gold's Gym in Venice Beach, California and has been pumping iron for seven decades.

He returned to the stage specially to claim a new world record for the oldest active participant in pro bodybuilding.

Andrew, a former Pro Master Mr America, has spent his entire career promoting clean, steroid-free bodybuilding and founded the National Gym Association in 1979.

He helped train Terminator star Arnie in his earlier competition career and remained close to the bodybuilding community all his life.

Photos shared on Instagram show Andrew proudly holding his trophy and medal with a backdrop celebrating his 100th birthday.

He said: "I wanted to show that age is just a number. The body and mind can still achieve greatness if you never give up."

Gold's Gym in Venice Beach, often called the 'Mecca of Bodybuilding', was a key training ground for both Andrew and Arnie during the golden era of the sport.

The gym gained global fame through its association with Arnie, who helped popularise bodybuilding through films and competitions.

The new world record was confirmed after the event, with organisers hailing Bostinto’s lifelong dedication to fitness and natural competition.

(MJ Leidig/newsX)