A 42-year-old woman was crushed to death while attempting to lift a 400-pound barbell at a gym in Mexico City.

The victim was working out at Fitness Sport on Monday when the barbell fell over her neck as her daughter and another man looked on in shock.

Surveillance video captured inside the training facility shows the woman stepping under the barbell, which appears to have at least four weighted plates on each end.

She seems to have control of the heavy barbell for about four seconds, but then it drops over onto her neck, causing her to slump toward the ground.

Gymgoers subsequently race to her side and lift the metal off her as she quickly falls backward, unconscious. One man turns her to the side.

The man then quickly steps away from her as she starts to bleed from her head area.

Paramedics from the Red Cross found the woman with no vital signs and declared her dead at the scene.

Authorities have yet to release the name of the victim. The Mexico City Office of the Attorney General is investigating the incident.