KRASNAYA POLYANA, Russia -- Olympic officials are trying to determine why a worker on the track used for sliding sports at the Sochi Games was in the path of a speeding bobsled that crashed into him, causing leg injuries and a concussion.

A forerunning sled sent down the track to make sure conditions were suitable for two-man training crashed into the worker Thursday at the Sanki Sliding Center, an incident that could have been far worse and immediately harkened memories of the on-ice death of a Georgian luger at the Vancouver Games four years ago.

The unidentified worker broke both his legs and was airlifted to a nearby hospital where he underwent surgery and was said to be doing well, an Olympic official told The Associated Press on condition of anonymity because medical information on the worker has not been released.

Sliding officials who reviewed video of the incident saw three men working near the finish line, two of them safely scurrying over the wall as the bobsled neared. The subsequent investigation quickly revolved around suspicions that the workers could not hear any announcement that a sled was coming down the track.

One possibility was that the man, who was using a motorized air blower, simply may not have been able to hear any announcement.

"We still do not know why he was in this zone and exactly what happened,'' International Olympic Committee President Thomas Bach told The Associated Press shortly after the crash.

Given that the sled had not crossed the finish line, it probably was not braking. But it's also unclear how fast the sled was going, since it was only a forerunner, which precedes training sessions and competitions to make sure things like the timing system are operational. Regardless of its speed, any sled at that area of the track would generate massive force.

"According to standard procedure, a warning signal was given ahead of the forerunners' bob beginning its run on the track,'' Sochi organizers said in a statement released more than three hours after the accident. "The reasons for the icemaker's presence on the track after the warning signal are currently being determined.''

Bobsled training was held as scheduled, albeit with a delay of about 35 minutes. The inaugural Olympic luge relay also took place at the venue later Thursday night, without interruption or incident.

Following the crash, workers replaced part of the lighting system bolted to the roof over the section of the track where the incident took place. Other workers cleaned small plastic shards of debris from the ice.

Loudspeakers in the finish area were working during training after the crash, though there has been at least one incident when the public-address system at the facility -- an absolutely critical part of the track's safety plan -- failed.

It went silent when the U.S. and other international luge teams visited the Sochi track for a training session in November after electricity was lost. That impacted lights, timing devices and the speaker system that allows sliders up top know when sleds at the bottom of the chute have been removed and the track is clear for the next competitor.

In turn, it also tells people in the finish area that a sled is on the way.

"We didn't really know what was going on,'' USA Luge coach Mark Grimmette said in November, when detailing how training was interrupted.

The Sochi track was designed to be safer following the death of luger Nodar Kumarishtavili at the Whistler Sliding Center in 2010. His fatal wreck came just near the finish line, and in an eerie twist, Thursday's mishap did as well.

There have been no major crashes in practice or competition at the track during the Sochi Olympics.

"To be honest, the ice is phenomenal,'' U.S. skeleton racer Katie Uhlaender said following the first two heats of the women's competition, several hours before the mishap. "It's better than it was in training and whoever they got working on the ice, kudos, because they are doing Olympic level work on the track. It is fast and it's fun.''

Mishaps like the one Thursday are rare, but have happened in the past. In 2005, U.S. skeleton racer Noelle Pikus-Pace was struck by a bobsled in the outrun of a track in Canada, shattering a leg and ultimately causing her to miss the 2006 Turin Olympics.