Encouraging Signs From Liz Stephen

One of the more exciting stories out of the early season FIS races in Muonio, Finland was the strong performances from Liz Stephen. Now, being a cautious, data centric guy, I also tend to be a bit of a downer. So I am loathe to predict much based on a single race, although there have been other signs of dramatically improvements from her, such as her dominant win at the Climb To The Castle roller-ski race. Still, I remain only cautiously optimistic.

One interesting way to look at things is this. Stephen was only 4.5 seconds behind Justyna Kowalczyk in the Muonio 10k freestyle race. If she had been the same percentage behind Kowalczyk in every interval start distance race last season, Stephen would have accumulated 7 top tens and 4 podiums. So the big question in my mind is (ignoring the question of whether Kowalczyk had a good day that day) was this Muonio race more like Stephen’s ceiling, or her average? If it’s more like the former, than I’d say she has a decent shot at maybe 1-2 top tens this season, but still a significant long shot for a podium. If this was more like an average race for her, then, well, we’re in for an exciting season indeed. And of course there’s plenty of room in between those two extremes.

For completeness, let’s look at graphs that compare Stephen’s results in the Muonio freestyle and classic races versus only the top 30 in each respective race that’s she’s face before in the past. First the freestyle race: Read more

Stephen’s Climb to the Castle Margin

Liz Stephen destroyed the women’s field this weekend in the annual Climb to the Castle rollerski race. The margin, just over 5 minutes in a race that took the leaders between 40-45 minutes is certainly impressive. But I think that margin doesn’t provide much useful information.

Time trials that are most useful as gauges of performance trends are the ones that have the most stable, repeatable conditions. I believe Climb to the Castle has everyone using identical roller skis (at least that’s my recollection) and that helps. But as noted in the coverage, road and weather conditions can pretty severely impact times. In that light, the fact that Stephen covered the course more than a minute faster than last year in worse conditions is certainly a more reliably good indicator.

But even then, it’s sort of crucial to note how the race dynamics played out. Stephen skied alone basically the whole way this year. Last year, it sounded like she skied alone for over half the race. That will tend to make those efforts more similar to those produced by a interval start race, which are easier to compare, I think. For example, it’s hard to read much into the fact that Sargent skied around 2.5 minutes slower this time around, since once Stephen was off the front it’s easy for “group racing” mentalities to take over common in mass start events that slow the pace.

Even if we ignore all that, consider than Sargent and Diggins were around 12.3% and 11.7% behind Stephen. Looks at their head-to-head results from recent history, it’s hard to believe that Stephen really is that much faster than Sargent and Diggins:

Diggins was actually frequently faster than Stephen last season, and even then it was unusual for the margin between them to be more than 2.5% in either direction. Even Sargent, who had somewhat of a rough season, was almost never more than 10% behind Stephen.

As a data guy, I’d love to see Climb to the Castle run as an interval start race, which would somewhat improve it’s use as a benchmark, but you’d still have a hard time accounting for differences in weather, particularly wind. But obviously, that’s logistically more complicated.

How long will Freeman and Randall remain on top?

Kris Freeman and Kikkan Randall have been basically the top US skiers for quite some time now. (I’m sort of brushing Andrew Newell under the rug here, mostly just due to time contraints. I’ll do a follow up on him next week.)

Freeman has been more or less unquestionably the best US male distance skier for what seems like forever, and Randall has been fairly dominant domestically in both distance and sprint events. How long can this last? Not forever, of course. Nothing lasts forever.

But it seems like the shift may happen sooner on the men’s side than the women’s. Here’s what I mean:

This shows the head-to-head results of Freeman against a handful of the better US men’s distance skiers in recent years. Certainly, Freeman has way more wins (above zero, in the pink) than losses (below zero, in the blue). But the gaps are generally narrowing.

Now, there’s a big caveat here in that I can’t say much about whether Freeman is getting slower, or these guys are getting faster, or even if Freeman is getting faster but these guys are getting faster faster. (That made you think for a second, didn’t it?) Or maybe they’re all getting slower, and Freeman is getting slower faster. (See, now I’m just having fun messing with your head.) The point is that these are just relative comparisons, not absolute ones.

In any case, what does the similar picture look like for Kikkan Randall? Read more

How can we assess performances in stage race pursuits?

As with most stage races these days, the Tour de Ski included some handicap start pursuits. Generally, the athletes will start in a staggered fashion based upon their time back in the overall standings, and the first person to the finish line wins the stage.

This creates some very unusual incentives for the athletes, depending on where they are in the overall standings. Many of the athletes are no longer really racing against each other, only those skiers who happen to be near them in the overall standings. For example, there’s no really sense in which Therese Johaug was racing against Liz Stephen in Thursday’s pursuit. Johaug only really cared about maintaining the gap behind her and trying to catch the leaders.

This means that isolating the times for just that stage is an almost useless way to gauge performance. Johaug, for instance, skied that stage around 15 seconds slower than Stephen, but we probably don’t think that that means much about Stephens’ ability compared to Johaug’s.

So I wonder about these things when I read stuff like this, or this, talking about how well Stephen and Freeman skied in the pursuit based on their times for just that stage. By my calculations, Freeman had the 11th fastest time of the day and Stephen the 13th. But that alone doesn’t mean much to me, since many other skiers were really only racing against the skiers near them, rather than the whole field.

If an athlete says they had a good day, of course, I’m inclined to believe them. They alone know how their body felt and whether it was a good effort. But, you know, I like to measure stuff, so let’s try.

Let’s compare Freeman and Stephen only to those skiers who started near them in the pursuit. Specifically, how did Freeman and Stephen’s times for the day compare to their historical performances against these skiers? Better than average? Worse? About the same?

Here’s the relevant graph for Freeman: Read more

Liz Stephen’s Distance Preferences

I was skimming FasterSkier’s write-up of the Tour de Ski prologue yesterday and noted their comment about how Liz Stephen “… is generally stronger over longer distances, performing better in 10k’s than 5k’s and even better still in 15k’s.”

That has been my informal impression as well, but I was suddenly skeptical about whether her actual results would bear that out as clearly as you might think. Specifically, I started wondering whether this may be a situation where how you measure results has an impact on how we perceive their quality. For instance, here are her WC level distance races, filtered down to only 5, 10, 15 and 30 km distances, measured by finishing place:

In 2009, longer distances were definitely better. Then things looked kind of mixed in 2010 (generally an off year), before returning to normal in 2011. So far this season, this look fairly mixed again, although with only a single race over 10k.

However, the longer races (15k/30k) are usually mass start or pursuit races. They can sometimes have smaller field sizes and are often paced much slower. (Although I think the difference is probably not as pronounced with the women as it is with the men.) If we look at the percent behind the median skier, which corrects for some of the differences between interval and mass start races, we get this:

Things look the same for 2009: noticeably better at the longer distances. Now, though, 2010 doesn’t look “mixed”. Rather, it seems she skied quite a bit better that year in the 10k’s (again, having a generally off year). But then both 2011 and 2012 look fairly mixed to me, with some good races at several different distances.

So I think her results have displayed a modest tendency to be stronger in longer distances, but not quite as much as you might think by looking only at her finishing place.

Rogla Distance Races

Oh yeah, there were some distance races in Rogla on Saturday too, huh?

Once again, this will be short on the words; just some pretty pictures. The US women had another strong outing:

Once again I’d note the continued downward trends for Holly and Kikkan and the generally flat trend for Liz. (Ida still has too few races for trends to be particularly meaningful.) In particular, I would emphasize that Kikkan’s classic skiing is showing the sort of trend her freestyle skiing has shown for a few years now:

Alex Harvey and Devon Kershaw were probably hoping for more on Saturday, and although their results weren’t terrible, they also weren’t all that great (for them):

The final thing I’ll note is that I noticed that the Russian women put three folks in the top ten on Saturday, a fairly strong showing for them. A sign of a resurgence for the Russian women? Well…

In Ivanova’s case, that race appears to be at her ceiling (or floor, I suppose if we associate down with better performance). As for Iksanova and Medvedeva, it’s still a bit early to tell, but it’s a good sign for those ladies to be starting out with results in the negative zone of these graphs.


Davos Recap

North Americans

Each weekend seems to be an interesting mix of results for the North Americans. Starting with the women (Davos result circled in blue):

Compared to this season, that was an off day for Kikkan, but compared to last season that was pretty typical. Part of me wonders if she dialed it back a bit late in the race when she knew she wasn’t feeling strong to save some energy for the sprint. But as you can see from her graph, if that’s going to be her “bad” race this season, she’s going have a strong set of results this year.

I’m very cautious about jumping on bandwagons when someone pops a good race or two, but Holly Brooks is beginning to convince me. That’s three good (and one OK) distance results in a row now. More importantly, I like the direction her trend is heading. It’s still early, so it’ll only take a few mediocre races to flatten that trend out, but so far it looks promising.

You can’t deny that Liz Stephen has had some strong results so far this season. My only concern is that they have all been roughly where we’ve seen her topping out before. Can her good days inch up towards the top ten?

As for the men: Read more

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