How deadly was gladiatorial combat?

Next Wednesday I'll be lecturing in Ancient Civilizations on the gladiatorial games, so I was very interested to hear an archaeologist commenting on the subject on CBC Radio's As It Happens. The occasion was the analysis of gladiatorial remains found in Ephesus, now in Turkey. It seems that the wounds found were limited in number and type, suggesting that the combat was limited by certain rules and perhaps was not fought to the death. The Austrian archaeologists have found a number of fighters who seem to have been killed by a "squarish hammer-like injury to the side of the head," which they speculate may have been administered to wounded gladiators backstage.

Earlier research by a friend of mine, Prof Steve Tuck of Miami University of Ohio, research based on comparing ancient depictions of gladiatorial combat with medieval treatises of arms, suggested that the fighters were highly trained and supervised by referees. He and others have argued that most of the time gladiators did not die, or even suffer incapacitating wounds. They were too expensive and popular for that.

I'd be very interested to hear what Prof. Tuck has to say about the new archaeological evidence.