The Deadpool themed kart overturned at around during the event which took place in Livingston, West Lothian today.
A male driver and a female passenger were understood to be in the vehicle at the time, taking on the challenging course which involved navigating obstacles and ramps.
Emergency services were at the scene and the woman is said to have been taken to hospital with a suspected broken collar bone.
An eyewitness said: "They were in a Deadpool themed kart and went over one of the ramps, which looked about 2ft high.
"They then went around a bend and they clipped a tyre wall.
"The car just completely overturned.
"The driver, he managed to get out, but the woman was lying on the ground.
"She was conscious and the paramedics were attending to her. I think she has a broken collar bone.
"They closed the track and stopped the competition for about an hour and 40 minutes but it's started back now."
The event, the first of its kind in Livingston, was organised by charity Livingston Round Table.
One of the organisers, Ian Smith, said: "There was a crash. Medics said the woman was ok but were going to take her to hospital to get her checked over."
The Scottish Ambulance Service has been approached for comment.
Ian Smith added: "The woman has a suspected broken collar bone.
"We try not to let these things happen but everyone has safety gear and helmets on.
"I believe they are both ok. I think the driver has suspected concussion.
"We are of course just hoping they are both going to be fine.
"You have got to put your hands together for anyone who comes and does an event like this because it's all for charity.
"We are raising money for a good cause, we are raising the profile of the round table and we just want everyone to have a good time and be safe.
"It's a fantastic event, the last thing we want is for people to be seriously hurt."