We'll get to Cris Collinsworth in a minute, but first let's talk about imperial Rome. Contemporary depictions emphasize the debauchery of the era, usually by illustrating either competitive or persecutory bloodsport in the Colosseum. Ridley Scott's 2000 Oscar-winner for Best Picture suggested however that the thrill in watching another human being die was not without a thin thread of morality woven into the gladiatorial exhibition. The pollice verso, the emperor's turning thumb, offered a defeated competitor reprieve from death if his performance was judged by the spectators to be conducted with skill and valor. Usually this just meant a gladiator earned himself another day or two of living. But I'm guessing that when you were on your back with a sword to your throat, watching that thumb go up must've felt like being Caesar himself.

Modern sports fans would point to MMA as our version of bloodsport, but this is mostly due to the fact that blood makes regular appearances and also that 1988 kickboxing movie. But MMA isn't actually bloodsport—if it were, submissions wouldn't end fights. Nobody, except psychopaths, really wants to see a death in the ring or octagon.

Motorsports fans live with the reality they may see a death at any time, though these are almost always accidents and not a process of competitive spirit (Kyle Busch excepted). Wrecks are celebrated by some NASCAR fans not for the danger but the spectacle of a dozen objects moving very quickly while on fire.

As a species, we've outgrown whatever thrills we once found in watching another human being's life shortened—except to many fans and commentators of the NFL who criticize the "targeting" rule introduced this season. They say it turns football into "two-hand touch". They say it's "ridiculous" and "sissy". They say you might as well "put skirts" on the players.

We know that playing in the NFL increases an individual's likelihood to suffer dementia and early death—and we know it through the experiences of those who played in the league before ESPN and SportsCenter helped, if not create, then commodify the "big hit," before anything mattered other than you stopping the guy with the ball as early as you could. Helmet-to-helmet collisions happened, sure—but the amount of force dealt to the skull was a fraction of what it is today, both because of a change in fundamentals and factors I'll explain momentarily.

Which brings us to Cris Collinsworth's criticism of the targeting rule during last night's broadcast of the Ravens-Steelers game, in which he took issue with the rule and suggested "playing like they did 50 years ago" is superior to the "new age" of the NFL, with all the protections it affords players. "In any other era," he said, "this is called a great football play."

Except a lot has changed since 1961. Advances in nutrition and strength training sciences make today's players unrecognizable to those 50 years ago. Steelers free safety Ryan Clark, the player penalized in the above video, weighs 210 pounds and runs a 4.34 40-yard dash. His counterpart in 1961, Willie Daniel, came in 30 pounds lighter and in a year when the fastest measured 40 time for a a defensive player was 4.5 seconds (the 40-yard dash as a scouting tool was invented in 1960, so times are both spurious and difficult to locate).

Meanwhile, Ravens tight end Ed Dickson weighs 250 pounds and runs a 4.59 40. His 1961 counterpart, Browns tight end Gern Nagler, weighed all of 190 pounds.

The hypothetical maximum impact force absorbed or dissipated by a Clark-Dickson collision is almost twice that of their 1961 counterparts. Helmet technology has improved, but there's a limit to how much force can be absorbed in a shell of the conventional shape and size.

Meanwhile, science keeps making players bigger and faster while evolution lags behind in making bone tissue and neurons stronger.

So when fans and commentators support helmet-to-helmet hits and boo the "sissifying" of the NFL, they are voicing support in subtext for shortening and/or reducing the quality of life of the players on the field—taking days away from their lives rather than adding them, as happened in Rome. They want their bloodsport straight, no chaser. Collinsworth, a former wide receiver who ran crossing routes, should know better than to pander to this impulse. Maybe he took too many hits.