Sunday, July 26, 2015

Rare Midsummer Wavesailing Session

Summer in SW Florida is generally a really bad season for windsurfing. It's rarely windy enough to plane, even with the biggest boards and sails. But yesterday was an exception, with a big low pressure system roughing up the Gulf of Mexico and bringing a stiff onshore breeze to Wiggins Pass State Park. I got out on a 106 liter Exocet Cross II board and a 6.4 KA Kult sail and took some video with my GoPro. The song in the video is by the Misfits.

July Wiggins 7-25-15 from James Douglass on Vimeo.

Rare windy day in the middle of Florida's stagnant summer season. I'm riding a 106 liter Exocet Cross II and a 6.4 KA Kult sail. Music is the Misfits.

Sunday, July 12, 2015

Post race analysis of SpeedCoach SUP 2 data

Today was the second of the CGT Summer Time Trials paddle races in the Imperial River. For this one I used one of the shop's demo boards: a 14' x 27" 404 v3 raceboard in PVC construction. The board is 2.25" wider than my own board (Fanatic Falcon), making it a lot more stable and a wee bit harder to maintain at top speed. My time was 47:54, second place after Mark Athanacio who got 46:34. Both Mark and I were slower than we were in the first race, probably because we weren't drafting each other like we did that time. Also it was really hot- 31C already when the race started.

This was the first race where I used the NK SpeedCoach SUP 2 and heartrate monitor during the race. Over the last week I've been fidding with the SpeedCoach a lot and figuring out how to do some more stuff with it. There are two formats that the device can export data in: .csv and .fit. The former file type is a data table that can be opened in Microsoft Excel and used to make graphs, etc. The latter includes latitude/longitude coordinates and can draw your path in a mapping program. It's not entirely straightforward to draw your path, though. Here's how I've done it so far.

1. From the "NK Link" program that goes with the SpeedCoach, you export the data as a .fit file.
2. You upload the file to an online fit to tcx converter and download the .tcx file.
3. You use the website "GPS Visualizer" to generate a Google Earth format (.kml) file from the .tcx file. GPS Visualizer gives you lots of options for the conversion. I picked "colorize by speed" to show different rainbow colors to my track depending on how fast I was going. I'm not satisfied with that feature, though, because the colors aren't a smooth blend. My track just looks like a birthday confetti of colors and there's no easily readable key to what color is what speed.
4. You download the .kml file produced by GPS Visualizer and open it in Google Earth. Then you can get whatever zoom and angle you want to view your track.

I've combined the GPS track and some of the data from the race into the graphics below. Getting the axes to look right in the Y versus elapsed time graphs was tricky. I had to tell Excel to use 0.000694444 (which is [1/24]/60) as the major unit on the x axis so that the numbers would go minute by minute instead of in weird decimals. Also, you need to make the graphs as scatterplots, then choose "no markers" for the markers and add a connecting line. If you try to make a line graph directly it doesn't work as well. Anyway, here are the pictures and some story to go with them:

The course starts at the dock at Riverside Park in Bonita Springs, and goes East, downriver, towards the Gulf of Mexico. The river is tidally influenced so sometimes, like this morning, the water actually flows upriver. So we were paddling against the current a bit on the first leg. You can tell that going upriver was favored because of the boost of speed I get at 17 minutes, which is right after I turn around the downriver buoy and start coming upriver with the tide. The next part of the race I mostly get slower and slower, which is probably due to a combination of fatigue, my technique slipping, less favorable current, and the upriver section being narrower with more bends.
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Looking at the heart rate graph you can see some neat patterns that don't show up in just the speed alone. One is that after the strain of the initial 90 seconds of sprinting, my bpm actually declines for a few minutes. That's because I'm drafting behind Brandon Gunderson's Hobie Apex 4R 14-5.75. I didn't have to paddle as often or as hard to maintain my speed then as I when I wasn't drafting. I passed Brandon after 5 minutes and he drafted me off and on until the buoy turn at 17 minutes when I lost him. Even though I was a little faster, it might have been a good strategic move to keep Brandon along and have him lead for a while so I could rest. My heart rate got really high going hard upriver in the blazing heat, sometimes getting above my age-based maximum safe heart rate recommendation of 184 bpm. At 25 minutes I could feel my heart skip a beat and thud in an uncomfortable way. That happens to me occasionally when I'm in the middle of a long hard stretch, but this is the first time I got to capture it on the heart rate monitor. I eased off the throttle to recover back down to 170ish bpm, and tried to keep below 184 until the very end of the race. It's interesting that my speed was getting slower and less consistent in the last 25% of the race even though my effort (heart rate) was steadily high. That might have something to do with my technique slipping. When fitness trainer Mark Athanacio (who had started about a minute behind me) passed me on the way to the upriver buoy he reminded me to straighten up and recover a bit between strokes to get a better breath and to be able to load more weight onto the next stroke.
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I find that stroke rate is the hardest thing to interpret from the SpeedCoach data. For one thing there are always some spikes of weirdly high or low stroke rates. Low stroke rate might happen when switching sides paddling, and apparently high stroke rate might be the result of the sensor getting bumped or jostled by stepping around on the board or rocking in the waves. Despite the blips, there does seem to be a trend of high stroke rate being associated with faster speed. I think one of my instincts when I get tired is to take slower but deeper strokes. However, in terms of speed gained vs. energy spent, it might be better if I can train myself to keep a relatively fast tempo when I'm tired but reduce the power a little to not get exhausted.

Although this post has been almost all about me, I should make sure to congratulate everyone who raced today. It was a tough, hot day, and lots of people still trucked through the whole course, many of them without the benefit of fancy raceboards and weed-shedding fins like I had. I saw more than one birds' nest of pine needles and sticks shake loose from finishers' fins when they finally stopped paddling at the finish line. I'd say weed fins are essential for freshwater paddling in Florida even for non racers.

Friday, July 3, 2015

Got a new GPS gadget - SpeedCoach SUP 2

This afternoon the UPS delivery person dropped off my new geeky toy - a SpeedCoach SUP 2. It's a GPS with a high refresh rate designed to give accurate, by-the-second speedometer readings, and it has an internal accelerometer that can sense every paddle stroke you take. (It can display your strokes per minute and your distance traveled per stroke, the product of which is, of course, your speed.) Also, it uses bluetooth wireless communication to talk to a heart rate sensor that you wear around your chest. The bluetooth lets you extract the data from the unit to your PC for analysis, which I think is super cool. You can also use the wireless to download timed interval "workouts" to the SpeedCoach, which will then tell you when to go fast, when to rest, etc. There are five workout programs already in the machine when it comes out of the box, and you can tweak them and save them if you want to.

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I had to rush to get on the water to try the toy today because the radar showed a thunderstorm coming in from the east. I did a 1.61 km (1 mile) paddle downstream in the Imperial River, then took a rest and did the same thing coming back upstream. Going downstream I didn't start the SpeedCoach data recording properly, so I didn't get any data for that section. Going upstream and upwind after I was already a little tired I didn't get the most impressive times, but the data was still useful. Here's what it looked like when I graphed it in Microsoft Excel:

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 photo speedcoach3july2015b_zps7xiqwu6w.jpg

Speed- It took me 20 seconds or so to get up to speed. Quicker acceleration is something I need to work on, since this could really hurt me in a race with lots of buoy turns where you have to stop and then accelerate again. I also notice that there are lots of little ups and downs in the speed, which might have to do with wind, current, and water depths changes as I was going up the bends of the river. I definitely noticed just by looking at the screen on the SpeedCoach that I was a lot slower in shallow water, and a lot faster when I could find an eddy in the downstream current. I'm sure there's a "human element" to the ups and downs, too, with my wavering will and focus. Strokes per minute- I take about 56 strokes per minute on average, but when I take more strokes per minute I'm faster. There are times that my stroke rate seems to suddenly dip really low, which may be when I'm switching paddling sides or may be when the accelerometer fails to pick up strokes. Heart rate- My resting heart rate (not shown) is 65-70 bpm. My "warmed up" heart rate (after paddling hard for a mile then taking a couple minutes to rest) is about 120. It took about a minute of paddling hard for my heart to go from 120 to 170ish, then it gradually got up to 180ish after about 10 minutes. I think around 180 is my hard-workout max.

Hopefully the data this gizmo delivers will give me some better insight into what works and what doesn't work for going faster. :)