Who dopes, and why
Eddie asked in a comment, why do sprinters and throwers get busted for doping more often than distance runners? Do they dope less, or just get caught less?
I’d say, “both.” First, the payoff from most doping agents is greater in the speed and power events than in the endurance events. This is a fancy way of saying that the limiting factor of how far you can throw a little iron ball is how strong you are, and the limiting factor of how quickly you can cover 100m is how fast you are (both top-end speed and acceleration) and both of those limiting factors can be directly affected by things like anabolic steroids, human growth hormone, and/or testosterone. Distance running is limited by so many different factors, from subtleties in physiology to simple matters of how quickly you can transfer oxygen from the air to your muscles, that doping offers fewer clear payoffs.
Second, because of the complications of doping for endurance, it’s harder to detect the performance-enhancing agents. Most of the ones that address endurance directly simply mimic the effects of being well-trained; some athletes use the strength/power agents (steroids) to allow them to train harder and recover faster, arriving at competitions free of the direct signs of doping but carrying the benefits of pharmaceutically-enhanced training. This is why out-of-competition random testing was created, but it probably makes the potential downside (the odds of getting caught) lesser for distance runners.
(The former East German sports complex supposedly used steroids this way, and 1976-1980 marathon gold medalist Waldemar Cierpinski supposedly appears on their doping records. However, the IOC has been less willing to pursue and redistribute the medals won through the wholesale abuse of the G.D.R. than they have been those won by Marion Jones.)
Most of the performance-enhancing substances used by distance runners, such as EPO (on the rise since the ’90s) and blood doping (favored in the ’70s and ’80s) are essentially taking existing biology and making it more so. EPO, for example, is made to treat cancer patients whose red blood cells have been decimated by chemotherapy; in a healthy athlete, it allows the blood to carry more oxygen. Cycling has been plagued by these agents because, oddly enough, the bicycle itself is a leveling agent, a mechanical means to erase the mechanical differences which would make one runner more efficient than another one with the same oxygen-transfer capabilities. There are new blood tests for EPO, but it’s still tough, and the testing is supposedly still lagging behind the alleged abusers.
But I think the first factor is the more important one, because the fact that doping agents aren’t as direct in distance running means that the general state of competition isn’t as distorted by them even if they are used pervasively as it is in the speed and power events (or cycling).
Which brings us to “why.” The classical profile of a doping athlete goes in two bins: the mediocre performer who suddenly breaks through with fantastic performances (e.g. Tim Montgomery,) or the longtime top performer who uses doping to extend their career (e.g. Maurice Greene, allegedly, or Regina Jacobs.)
Laurel points out a relevant Scientific American article (via 3 Quarks) which applies game theory to doping, mostly in cycling. The premise is that as long as they payoff for doping is high and the penalties relatively low, it will be pervasive, but that federations have the power (with some bold steps) to change the game between dirty and clean such that avoiding performance-enhancing substances is the smart choice. This means making the penalties draconian (which requires bulletproof testing, unfortunately) and making it easier for athletes to believe they can compete without doping. (Read the article for a better explanation of these suggestions.) These are things track (and particularly distance running) is doing much better than cycling, but for all the reasons already discussed, the game theory tips much less in favor of the dirty athlete in endurance events.
Now Playing: The Wake-Up Bomb from New Adventures In Hi-Fi by R.E.M.