A personal trainer told a jury that his jaw was broken by a colleague after aligning with a client.
William Aiden, 26, claimed that Karen Peterson, 29, punched him in the face on April 19, 2019 at Future Fitness in Shawlands, Glasgow.
Mr Eden claimed he confronted Mr Peterson as if he were treating an injured client.
The couple and the owner went to the staff room where he was allegedly killed before falling to the floor, he said.
Mr Eden claimed he spat blood and later received metal plates for his broken jaw.
“The injury is the most intense pain I’ve ever had in my life,” he said.
Patterson pleaded not guilty in Glasgow Sheriff’s Court to the mere charge of assaulting Mr. Eden with his serious injury, permanent injury and permanent disorder.
Mr Eden told the judges in evidence that he had a “professional disagreement” with Petersen, whom he described as a “friend”.
Prosecutor Carrie Stevens asked what was said.
The witness replied: “All I said was that his client’s care was over and he was not taking care of his client.”
“That’s why the client was in pain.”
Mr Eden claimed that Patterson, the owner of the gym, had set out to find Jason Evans, 50, before the three ended up in the staff room.
He said: “Karen told Jason to try to leave me and his business alone.
“Then I explained why I came to the conclusion I had and then he started attacking me.”
Miss Stevens later asked how Patterson attacked her.
He replied: “I was explaining my comfort and he was probably a foot or two away.
He almost turned his back on me and turned around and grabbed me by the left side of my face with his right hand while hitting me hard on the jaw.
“It was a full-blown cartoon.”
Mr Eden said he stumbled before falling near the reception where he spat blood.
He added: “Adrenaline kicked and I didn’t realize the harm at the time.
“It was the worst pain I’ve ever felt in my life.”
Mr Eden claimed Mr Evans had told him to leave and that Petersen “pushed the table and ran out the door”.
Mr Evans then took him to hospital for treatment.
Mr Eden said: “I thought my tooth was missing, but it was just the difference between a broken jaw.
The jaw was completely removed and I could fit my whole tongue in it.
Mr Eden said he had undergone surgery to reattach his jaw, which required a metal plate.
As a result, he said, the metal plate causes pain in the cold and he can’t eat anything like apples.
Mr Eden added: “I have a scar now.
“If I hit my jaw again, it will be permanently damaged.”
Defending himself, Michael Gillan told Mr Eden that he was “aggressive” in the dispute.
He added: “I suggest you hang him, try to punch him and he punches you.”
Mr Eden replied: “It’s utterly dishonest, as I have said I am not a trained fighter he is too big.
“Karen has a background in martial arts and MMA. I’ve never had a record of violence in my life.”
Petersen told the judges in evidence that he had tried to calm Mr Eden down in the staff room.
Defending, Michael Galen asked, “What happened next?”
Peterson replied: “He attacked me – he ran towards me, tried to punch me and was still screaming at me.”
Mr Galen said: “You say it was the only action you could take?”
Patterson replied: “There was no escape.
“The opening was only half a meter.
“I had a wall to my left and William was in front of me.”
Patterson said Mr Eden had to be stopped by Mr Evans as he was leaving the gym after the alleged incident.
The trial is set to begin on Monday in the presence of Sheriff Paul Cruzier.