Thursday, January 29, 2015

Tools for looking at run/rest schedules

If you've followed distance mushing for any amount of time you're keenly aware of the role that run/rest schedules play in the sport.  They can be both strategic and tactical, and can reflect the breeding decisions a given musher makes, as well as their training regimen (more on that in a bit).

I've posted a couple of videos on my Facebook page using Trackleaders tools from last weekend's Northern Lights 300 to look at how to use them to get a better understanding of how teams are performing against each other as they move down the trail, and how to use the replay function to watch interesting, and occasionally surprising, things happen during a race, based on how the teams move on the map.  In the latter video I looked more closely at Larry Daugherty, because there were some unusual things happening on his tracker that stood out from the rest of the race.

In Larry's recap of the race he talks about deciding that he was going to try to be competitive, and making adjustments to his run/rest schedule to be more competitive.  Of course, now we know that his team shut down on him twice, and the first place to look given his comments and given what happened is at how he rested his team.

During last year's Yukon Quest I wrote a short Python program to pull rest times out of a Trackleaders musher track.  It's available for download, but for the more visually-oriented, you can take a look at a musher's speed/time plot on their Trackleaders page.  For example, here's Kristy Berington's for this year's NL 300.  She won the race, so clearly the decisions she made worked well for the team she had and the training she'd done:

Reading this is absolutely straightforward.  The x-axis (horizontal) is race time - hours since the race start - and the y-axis (vertical) is speed.  This looks like a pretty standard schedule for a 300-mile race.  Her schedule looked roughly like:

        Run 7 hours, rest 6 hours
        Run 6 hours, rest 3 hours
        Run 5 hours, rest 5 hours
        Run 8 hours, rest 4 hours
        Run 7 hours to the finish

So, the longest of the runs were only moderately long, and pretty much in keeping with what we've seen be successful in other races.  None were what anybody would call very long.  There were four rests.  Note that the longest run was in the last half of the race, the second-to-last one, which was 8 hours.

Now, Larry said that his goal was to run long and rest long, as he'd seen other mushers, notably Allen Moore, do with a great deal of success.  So, let's take a look at Allen's successful Copper Basin 300 race earlier this month:

Again, time is on the vertical axis and speed is on the horizontal axis.  His schedule looked roughly like:

        Run 5 hours, rest 5 hours
        Run 7 hours, rest 7 hours
        Run 3 hours, rest 5 hours
        Run 9 hours, rest 2 hours
        Run 8 hours to the finish

Again, a few moderately long runs, four rests, and the longer runs in the second half of the race (also top speeds of 30mph in a few places - woo, Allen!  But those, sadly, are actually measurement errors).  Note, as well, that in mid-distance races with mandatory checkpoint rest, the run/rest schedule is going to be influenced by checkpoint location and layover rules.

So now we've looked at a couple of successful run/rest schedules, including one that Larry said he was using as a model.  Let's look at what Larry actually did:

        Run 7 hours, rest 7 hours
        Run 12 hours, rest 5 hours
        Run 8 hours, rest 6 hours
        Run 8 hours to the finish

Note that there are places in the third run and the run to the finish where his speed dropped considerably, and in one case where he actually stopped.  Those are the places where his dogs quit on him.

What pops out here is that he only did four runs over 300 miles, while Kristy did five runs in the NL 300 and Allen did five runs in the CB 300.  Note as well that his long run was comparatively quite long (12 hours), that it was in the first half of the race, and that it was not followed by much rest.  His run/rest schedule does not actually look much like that of mushers winning at that distance, and is clearly one possible reason why his dogs quit on him several times.  And this gets back to the training question - if he hadn't been training for very long runs prior to the race his dogs were likely not in condition either mentally or physically to pull one off.

Eyeballing the curves it also looks like Larry lost more speed on the first run than Kristy did.  It might be interesting to fit a regression line to each and see how the slopes compare, but think it would only be a little bit interesting.  More interesting is that many top mushers have talked about leaving the start chute at the same speed they'd like to run their race, or about negative splits, where their speeds towards the end of the race are faster than their speeds earlier in the race.  Sebastian Schnuelle has talked memorably about being passed left and right by other teams towards the start of the race, and telling them "I will see you later."  And nearly always, he does.  Going out fast may or may not hurt but it's not clear that it helps.

This plot (the speed vs. time plot) is an incredibly handy tool for looking at run/rest schedules.  One enhancement I'd love to see would be the ability to overlay multiple mushers on the same plot, which would allow us not only to compare rest durations and locations, but also speeds while moving.  In the meantime, my script has the option to output the results in CSV format, which is handy for loading into a spreadsheet or into a data analysis package like R or NumPy.

1 comment:

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