Aside from being a yummy holiday treat, Thanksgiving turkey is a term used (in North America, at least) to refer to ski racers who come out of the gate kicking everyone’s pants off in November or December and then fizzle out for the rest of the season.  A friend urged me to write a post on this subject recently, so here it goes…

If you’re unfamiliar with high level ski racing, you might need a little background.  The way that elite training works is usually built around the fact that the big, important races that you really want to be skiing fast for are later in the season in February or March.  That means that skiers try to structure their training through the first part of the racing season such that they get steadily faster.  The concern is that if you go into the ski season in November already “peaked”, it can be very difficult to maintain that level of fitness for the next 2-3 months and you end up “burning out”.  There’s lots of complicated physiology and training principles at work here, that I’ll likely get wrong if I try to explain.  So let’s just accept that this is a real concern and leave it at that.

I’m not here to dispute the idea that this happens.  If you go looking for instances of skiers going really fast early in the season and then flaming out later on, you can certainly find them.  (And I’ll do just that later on in this post.)  The “statistics” question here would be whether there’s an overall trend.  Do skiers who go really fast early tend, on average, to end up skiing really slow later on?

Color me skeptical.  There are a variety of issues here:

• Reversion to the mean – Skiers who go unusually fast are likely to slow down, not because of some “Thanksgiving turkey” effect, but simply because your subsequent performances are more likely to be closer to your average level of performance.
• How do we define fast? – When we talk about skiers who are “going fast” in November are we referring to skiers beating their competitors or outperforming their own past performances?
• Normal variation and small sample size – As I’ve remarked on before, skiers are not robots.  Their performances vary quite a bit from race to race, and this is in fact normal.  Comparing early and late season races for a single racer will involve comparisons of, at most, groups of 5-7 races.  More often we’ll see someone doing 2-4 races in November/December and then 6-8 in January-March.  Given the normal variation in racer’s performances, it might not be unusual at all for them to pop a great race in November, which might not mean anything at all.

All this will make any general trend very difficult to discern, but let’s see what we can see in the data.  Since comparing performances within athlete (going fast relative to your previous self) is quite a bit more complicated, I’m going to stick with absolute comparisons.  The other headache in this investigation is deciding what group of skiers to look at.  Do we only want to consider skiers with a podium in Nov-Dec?  A top 5?  Top 20?  All of these things are possible, but to prevent this post from spiraling out of control, I’m going to just use FIS points.[1. I’ve tinkered a bit with looking at finishing place, restricting by different subgroups, and I haven’t noticed anything significantly different than what we get with FIS points.  But there’s an endless number of ways to slice this and I’m sure I haven’t covered them all.]

Focusing on distance results, I divided the season into two halves: Nov-Dec vs. Jan-Mar.  Then for each athlete and each season I calculated some relavent summary statistics on their results for each half of each season.  First, let’s look at the median FIS point result in Nov-Dec vs. Jan-Mar: Continue reading ›

Now for some of the folks across the pond.  I’m less familiar with a lot of the European racers, so who I focus on will be largely dictated by what stands out to me in the data (or you can drop me a line if you think there’s someone I should put under the microscope!), not necessarily just who wins or earns a podium.

First the good:

I’m plotting all races, not just major ones since several of these skiers only have a few WC races under their belts.

Petr Sedov is an obvious standout here, particularly given how young he is.  Notice how little data there is on him!  I don’t have an “official” statistical take on this, but after having spent many hours hip deep in results data, I’m willing to put myself out there and say that skiers who suddenly appear on the WC scene going that fast (without the steady, year over year improvement over many seasons on the WC) either (a) flame out completely and you never see them again, or (b) end up being Per Elofsson/Petter Northug.

At the moment, most people seem to be leaning toward option (b), and I certainly don’t know anything to the contrary.  Time will tell…

Maria Rydqvist we’ve discussed before, and it’s certainly nice to see her show that her race last weekend wasn’t a fluke.  I stand by my claim that this isn’t really wildly out of line with her general talent level (just look at her past results), but as a guy, it’s always awe inspiring to see women have kids and come back quickly to elite athletic competitions.  Unbelievable.

Sjur Roethe is a name that (being a dumb American) wasn’t really on my radar screen, but he definitely seems legit and has a less frighteningly quick development pattern (compared to Sedov) which makes me worry less about whether he’s “for real”.  Chris Jespersen, on the other hand, has actually been a round awhile, and Saturday’s result (4th) is considerably better than anything he’s managed before.  He was 13th in a 15km in 2008, but all his other WC starts have been in longer events (30-50km) and range from 28th-72nd.  Has the Norwegian men’s distance squad suddenly turned a corner?  Personally, I always thought that the complaints about their deficiencies were a bit overblown, but I suppose we’ll see.  Predictions at this point in the season are sure to make one look foolish, but I’d be pretty cautious about expecting this kind of performance from Jespersen on a regular basis.

Mia Eriksson has had two good races in a row now, being at the better end of what she managed last year.  I wonder if Rydqvist has stolen a bit of the attention early in the season, but Eriksson’s race in Gällivare was a much bigger jump for a WC race than for Rydqvist.

Two skiers who’ve been on a steady (if somewhat slow) improving trend are Silvana Bucher (SUI) and Robin Duvillard (FRA).  As such it isn’t necessarily surprising to see them starting strong, but it certainly must be encouraging.

Actually of more interest to me were some of the worse performances.  Here’s a selection of well known men who turned in races that might be considered “bad”: Continue reading ›

In the run up to the World Cup season, I had been trying to think of ways to create a single graph that would do a decent job of communicating how good each person’s race was in the context of their past results.  I wanted something relatively simple and easy to read that would hopefully allow you to just scan down the results and get a quick read on how that day’s race compared to each skier’s historical results.

Here’s what I came up with:

First I’ll explain, and then I’ll show you the women’s version.

Obviously, each row is an athlete, in the order they finished, in this case the men’s 15km skate race on Saturday in Gällivare.  The red dots are the FIS points for each skier from that race.  The horizontal bars represent the middle 50% of that skier’s FIS point results from WC, OWG or WSC races over the previous three years.  If a skier had fewer than 10 WC, OWG or WSC races over that time period, I plotted the values for the actual races themselves rather than the horizontal bar.

So obviously, if your red dot is to the left of your bar, that’s a “good” race, and if it’s to the right of you bar that’s a “bad” race.  What’s relevant here is,

1. The location and width of the bar representing an athlete’s middle 50% of race results, and
2. Where the red dot is in relation to the bar

The blocks of color just mark out groups of ten skiers, hopefully making it a bit easier to scan through to and see roughly what place each skier finished in.  This is a “reduced” version, showing only the top 30 plus the North Americans.  You’ll note that the finishing places start jumping up after Noah Hoffman in 31st.

Ok, here’s the women’s version:

My intention with these graphs really is that they serve as just a snapshot, a quick way to put the race results in some context for each skier.  The hope is that they will lead to some more interesting things to look at in more depth in subsequent posts.

I didn’t this weekend, but going forward my plan is to have these up as soon as I can on the day of race for WC, TdS and WSC events, with almost no commentary.  (I can make similar graphs for sprint races using finishing place rather than FIS points.)  Then I’ll dig a little deeper in follow up posts.

Full versions, which include every racer, are below the fold.  They are big, so click through for the full versions.

Continue reading ›

I’m squeezing in the last preview post for the Canadian ski team just under the wire!

For both Ivan Babikov and George Grey I’m going to focus in on the distance events.  They both certainly do sprints in stage events like the Tour de Ski, but I think it’s fair to say they both have had somewhat more success in distance events.

Continue reading ›