Gear: March 2008 Archives


March 30, 2008

Speedo has put an immense amount of effort into developing faster swimsuits, and swimmers using their newest suit, the LZR racer, have broken 13 world records in the past 6 weeks. Understandably, FINA (the governing body for swimming) is somewhat concerned:
EINDHOVEN, Netherlands - The slick new swimsuit that has led to 12 world records already this year will be examined by swimming's governing body amid debate about the quest for speed in the pool.

"There are concerns about suits being like triathlon suits, which are thicker," FINA executive director Cornel Marculsecu told on Monday. "There are buoyancy issues. We have to review this."

There have been 13 world records set since mid February, 12 in the LZR Racer, a full-length body swimsuit made by Speedo, a brand of Warnaco Group Inc.

There's a lot of science in the LZR. Principally, there are a bunch of features (bonded seams, water repellent fabric) to reduce drag, but the most interesting one is that it's deliberately stiff and supportive around the waist:

The internal core stabilizer supports and holds the swimmer in a corset-like grip and helps them to maintain the best body position in the water for longer.

Body position really is important in swimming—when I was doing triathlon it was one of the things I found hardest to learn. I can't say whether something like this would have helped me and I don't know enough about the technology of swimsuits to say if any of this helps. I skimmed Speedo's site and they claim to have research that shows that these suits improve oxygen efficiency, which basically maps to performance. That said, it's certainly that case that your clothes can change swim performance: baggy suits create more drag and wetsuits dramatically increase performance due to bouyancy and (as far as I can tell) especially keeping your lower body high thus reducing drag even without the need to kick (cf. pull buoys).

The most interesting part of Speedo's site for me was the interviews with athletes who talked about how much they loved the suits and how nice they felt to swim in. The topic of the impact of technology on sports (and fair competition, and purity, etc.) has been discussed ad nauseum, but one thing that rarely comes out in such discussions is the user experience, namely that going fast is fun, and even small differences in your gear make a big difference in how responsive and fast you feel. One of the great things about racing is you get to use your very best, fastest gear—often stuff you couldn't train with every day, either because it's too expensive or (as with racing flats) it's too hard on your body to use all the time. Of course, after a while you get used to the good stuff and then it doesn't feel as great which is another reason why most athletes reserve it for race day. (I've heard this said by swimmers about shaving down as well.)


March 21, 2008

One of the things I've always found difficult about navigating with standard topo maps (and a major motivation for being able to download maps into my GPS) is the pain in the ass that's finding your position based on lat/long. Let's take your typical 1:24000 scale map of the Bay Area:

  • The scale is about 1" for each minute of longitude and 2.5" for each minute of latitude.
  • On the USGS quad I'm looking at, tick marks are every 2.5 minutes of longitude and every 3 minutes of latitude.

Using a map like this and starting with GPS readings, finding your position involves converting minutes and seconds to inches (with different scaling factors for lat and long) and then measuring to find the right point on the map.

It turns out—and I feel pretty stupid for not knowing about this already— that there's a much easier way: Universe Transverse Mercator. The basic idea is that you divide the earth into sectors which are small enough to be treated as rectangular and then you can describe any position within the sector by measuring the distance (in meters) from the corner. Generally your GPS can emit UTM coordinates and good topo maps come labeled with UTM grid lines, so finding your position is a simple matter of locating the nearest grid ref and doing a little interpolation. You can even get nice little map tools that let you measure UTM distances on maps of common scales (especially the 1:24000 scale used on the most useful topos). This is dramatically easier; I've known about it for less than 8 hours and I'm already quite a bit better at finding my position with it than I ever was with lat/long.