He walked out slowly towards the centre of the gymnasium before breaking into a trot at the event in South Africa.
Thabete then begins a backflip but fails to rotate enough in the air and instead of landing on his feet, he lands on his neck.
Thabete, from Umlazi in KwaZulu-Natal, South Africa, lay motionless in agony on his side before rolling onto his back.
Several people coming to his aid after the initial shock of what happened left the audience stunned.
The first man to attend to him lifted his legs up before several others joined in to help but Thabete died of his injuries.
South African bodybuilding magazine Muscle Evolution said the bodybuilding community was “shocked and saddened” by the news of Thabete’s death.
The magazine reported he was an International Federation of Bodybuilding and Fitness (IFBB) Junior World Champion in the up-to 75kg category.
He recently won under-23 in 75kg division of the IFBB Muscle Mulisha Grand Prix competition held in Johannesburg in July.
Thabete also finished runner-up in the division for senior men up to and including 80kg and at the event he successfully performed a backflip during his routine.
Posts on his Facebook page show he was dedicated to being the best in his sport and he often shared motivational messages on Facebook alongside images and videos of himself.
He recently shared a magazine article written about him on his Facebook page saying “wow god is good”. (Mirror)