A great matchup for the final between Ryun and Kastor. I came in thinking I would choose Ryun, the legendary highschool miler who went on to break the world record. But then, after going through the numbers, and watching the race videos, I ended up realising it was way closer than I initially thought - see the bottom for who I ended up picking. Here is my analysis, where I compared the athletes head to head in some of the categories presented
World Records: Ryun
None of Kastor's records were ever world records. Ryun held multiple world records. Ryun's 1500m world record lasted six years, his mile record lasted 8 years. His 880yard best was also the best time for 8 years [but multiple athletes were withinn 0.1 seconds of within a couple of years]
American Records: Kastor
Kastor's best record, her American marathon record still stands, Ryuns best record, the mile, was unofficially broken/tied 12 years later, officially 14 yrs later ). Since Kastor's is 14 years old already, and no woman is likely to break it anytime soon. Her record will have lasted longer than Ryun's. The fact that she is the only American woman to have ever run sub 2:20 (a magical barrier in women's marathon running gives her record, in my opinion, some added significance). And no woman has ever gotten within a minute of it, which is kind of crazy. It also needs to be taken into account that the mile has been much more rarely run by professional athletes [even during Ryun's time when it was more common, 1973 was the last 1mile run at the US champs]. Looking at the other records - Kastor set American records in the 10,000m (lasted 6 yrs), and the half marathon (lasted 12 yrs), road 15k (lasted 11 yrs) and the road 5k. She still holds American records in the road 10 mile, and 8k. Ryun has one other American record, in the 880y which lasted 8 years. While Ryun has an impressive list of American junior records that add to his legacy, it's hard to know how much weight to give them. Ultimately this is about GOAT runners, not junior runners, so I'm not convinced we should give junior records much weight. Kator's range of American records is just better than Ryuns.
Olympic Performances: maybe slight edge to Ryun - but pretty close to a tie
Ryun has a Silver and Kastor has a bronze. We have to analyze these accomplishments against the quality of the fields they ran against, and the margins by which they were beaten, and the opportunities they had. Kastor ran against a very strong Olympic marathon field, she was defeated by two former world record holders, Naguchi former record holder over 25k and 30k from her positively split 2:19:12 marathon in Berlin, and Nderebda the former world record holder over the marathon, 2:18:47. Radcliffe, the record holder at the time, was also in the race but DNFed. What was especially impressive about Kastor's run was how she surged over the final 10km to pick off many runners ahead of her. She ended up being beaten by Naguchi by 1 min, but she was gaining on the leaders through the very end. In the 1968 Olympics, at the height of Ryun's prime, Ryun competed against an arguably weaker field and was beat by 2.98 seconds (this would equate to being beat by 1:24 in a marathon if we extrapolate over the distance) a bigger gap. Of course, we can say the 1500 was at altitude and Kastor's marathon was in crazy heat. But in the end the conditions are what they are.
US championships: Kastor
Despite the fact that Kastor's best event is not even contested in the US outdoor championships, she still has more titles (5 vs 3).
Global medals: Kastor
Cross country is the heart and soul of our sport, the 2 silvers in XC are major accomplishments against fields of dominating east Africans + Paula Radcliffe. What's particularly notable about these performances is that in an Olympics, or world championships, the east African nations are restricted to only a few runners, but in XC, because of the team championships, the fields are actually stronger than the Olympics. Having 5-7 Kenyans and Ethiopians in the field makes breaking through into the medals very tough.
Kastor was the best American runner at the 5k - marathon while she was competing. She is a true GOAT distance runner. Ryun, while the best American MIDDLE-distance runner of all time, only has a 13:38 5k pb. Even during Ryun's time, there were several Americans running 10+ seconds faster, including Prefontaine 13:21, Paul Geis 13:23, Dick Buerkle 13:23, and George Young 13:29. Kastor was certainly a better 5k runner than Ryun was (relative to their genders), despite the event being outside both of their best distances. This was the tie-breaker for me in a very close decision. If Ryun ran a 5k in very low 13:30s, I'd be willing to give it to him.
In some sense, I think this was the toughest match for me to make a decision. I was expecting to go with Ryun, but was surprised when I thought about it a bit deeper. There are multiple ways to interpret the stats and present the data. I'm sure folks would disagree with me and I think that's reasonable. I thought I'd just say how I changed my mind. There is such legend behind Ryun, he was truly fantastic. But I think if I didn't give the stats a closer look, I would have been very biased by this legendary status.