Statistical Skier

A reader sent me an email over the weekend regarding the discussion that’s popped up over the fact that women compete in far shorter distances than the men in cross country skiing. He suggested that looking at men’s and women’s road marathon times (running) might be interesting.

I did him one better and grabbed the world record progressions for road marathons, half-marathons and 10k’s as compiled by the Association of Road Racing Statisticians. Here they are, expressed as the percent back from the men’s world record at that time:

Do not be surprised that these lines sometimes bend upward; if the men’s WR drops that’s the equivalent of the women’s WR falling somewhat further behind the men’s. So we’d expect these lines to bounce upwards on occasion.

Much of what we see here is unsurprising, of course. Once you actually allow women to compete in an event, they may start out really slow, but they’ll make pretty darn rapid progress.

I was surprised that all three distances appear to have largely stabilized at around 10% behind the men’s world record. More recently, the women’s marathon times dropped a bit suddenly starting around 2000. The half-marathon distance must get more attention with the men or something; the women set a record back in 1987 and then again in 2007, but nothing in between.

So how does this relate back to our skiing discussion? Several things. First, discussions about what distances the women ought to be skiing should acknowledge that however fast they might ski a distance right now, they’re likely to improve on that once you actually let them ski it. Someone arguing in 1972 that holding women’s marathons was logistically too difficult because they ran them 30-40% slower than men would be making precisely this mistake. I doubt that the current female World Cup athletes are likely to make nearly that much of a step forward if they started racing 50k’s, but surely they’d get better at the distance over time.

Second, a 10% difference in time isn’t very big. Now, I think it’s likely that if we could plot a similar graph for skiing, we’d see the values start to level off a bit higher than this, maybe 15-20%, since skiing revolves more around upper body mass, which might work against women somewhat. But assuming you want the men’s and women’s races to be roughly the same amount of time, either for TV or to create equivalent physiological tests, you’d probably be better off shooting for having the women race around 85% of the men’s distances or so.

That would mean (very roughly) a 50/40km event, a 30/25km event and a 15/12.5km event. And that’s certainly not what we’ve got now.

A number of Americans and Canadians participated in some big FIS races in Beitostølen, Norway this past weekend. Not all the results have migrated over to the FIS site yet, so I’m just going to focus on the classic distance races from Saturday. We should keep in mind throughout that, from what I’ve read, many of the North Americans were not necessarily trying to put together top performances, but rather tuning up before Drammen next weekend.

One interesting tidbit I should note is that the combined men’s results from Saturday represent the single biggest ski race currently in my database, with well over 400 participants.

Let’s start with the roughest look using FIS points:

I’m including Andrew Musgrave, since he’s an interesting skier from a “non-standard” skiing nation. As always, the meaning of FIS points can be tough to tease out, since it requires that we believe that the penalty system is accurately measuring the strength of the field. But generally it will capture a general sense of “good race” or “bad race”.

By that measure, it certainly seems like Babikov and Elliott didn’t have a great day, although they’re more known for skating. Simi Hamilton put together another strong (for him) distance race for a guy more known for sprinting. There’s just too little data for me to say much about Skyler Davis and it appears that Musgrave and Valjas both had decent but not spectacular races.

Let’s take a closer look at a few of these guys, using percent back difference plots. These plots look at head-to-head matchups against all the people in this race that a skier has ever skied against: Continue reading ›

With the biathlon World Cups taking a turn through my childhood backyard these past few weekends, I’ve been spending more time trying to come up with some nice biathlon plots.

Fairly early on with my race snapshot graphs I switched over with the cross country ones to show each athlete’s results compared to all their races and also compared to just those from a particular technique. Obviously that doesn’t really apply to biathlon, since they only skate. But just as in cross country, the different events (Sprint, Pursuit, Mass Start and Individual) can lead to systematically different percent back values. Mostly this is an issue in the pursuits and mass starts. So yesterday I actually only used mass start races for those graphs. But I really should make a two-column version for biathlon as well, so here they are: Continue reading ›