The 23-year-old sustained the injury while training at the PSX Olympic skicross venue at Rosa Khutor Extreme Park.
There were no immediate details of her injury, but the federation said she would not compete at the ongoing Sochi Games.
Russian host news agency Ria Novosti quoted a source close to the situation as saying the injury was a fracture of the spine with a dislocation, that she could not be transported to Moscow, and that an operation would be carried out at Krasnaya Polyana hospital.
Triple Olympic ski champion Jean-Claude Killy told Reuters: "It happens... it can happen everywhere. I've been in this business for many years, it happens. We are very sorry about it ... we hate accidents at the Games."
Frenchman Killy, who also acted as the chairman of the IOC's coordination commission for the Sochi Games, added: "I have been to the hospital myself a couple of times, so I know it can happen.
"Spine injury is very serious, that's an accident that happened because of a bad fall. We are sorry to hear about it."
The 1,200 metre skicross course at Extreme Park is a medium-pitch slope which features cambered turns, gap jumps, drops and flat sections.
The skiers race down the course in groups of four in a test of speed, skill and aggression with the first across the line the winner.
"It's big, some big jumps," Slovenia's Filip Flisar said after getting a first look at the course on Friday.
"It's cool. I think maybe they have to do some work on some of the landings but it looks good."
Komissarova's accident comes two days after a track worker at the February 7-23 Olympics was struck by a bobsleigh, suffering two broken legs.
The worker was hit by the "forerunner", which is sent down the track ahead of the official competitors to check for safety.
Russian ski jumper Maksim Maksimochkin was taken away on a stretcher on Wednesday night after crashing during practice on the large hill. He spent the night in hospital and was diagnosed with two fractured ribs.
On the slopes, Liechtenstein's medal hope Tina Weirather missed the downhill and super-G after suffering a heavy bruise when she fell in downhill training on Sunday. She was not entered in the combined.
Slovenia's Rok Perko broke his nose in a fall in men's downhill training, while French skier Brice Roger tore his anterior cruciate ligaments in the same training session and is out for six months.
Canadian Marie-Michele Gagnon dislocated her shoulder after straddling a gate in the super-combined on Monday. She returned for the super-G today but skied out.
In figure skating, Jeremy Abbott slammed into the barriers after falling on his opening jump. He lay grimacing in pain for almost a minute but then finished his programme.
Komissarova's crash, though, marks the first major athlete accident of the Sochi Games.
Four years ago, a tragic pall hung over the last Winter Olympics in Vancouver when Georgian luger Nodar Kumaritashvili died in a crash during a training run on the day of the opening ceremony.
- Sports & Recreation
- Jean-Claude Killy
- Rosa Khutor Extreme Park