Bicycle riding and nutrition

June 21, 2005 at 4:38 pm

Jim posted a comment on my century ride, talking about what I ate. He totalled up what I ate during that time period, and remarked on how small it was. I agree, though I get a number that’s even smaller than the one he got:

330 calories in Clif Bars
520 calories in Accelerade
250 calories bagel
55 calories Newton
250 calories pretzels
1400 ingested

That takes us onto the calories that I expended. The only good way to measure this is with something like a PowerTap, which is a wheel hub that measures how much force you’re putting into your back wheel. Integrate that over time, and you get power, and you can make a good estimate of how much energy you expended.

Without that – and I don’t think I’m likely to spend the money for a PowerTap or other power-measuring system, at least in the near future – you’re stuck with estimates, which suck. The number of calories you expend vary depending on the speed you’re riding, whether you’re riding in a group, whether it’s hilly, etc. I’m going to choose 500 cal/hour as a ballpark estimate. That means that for 5.5 hours, I spent:

5.5 * 500 = 2750 expended.

That doesn’t seem so different from what I ingested, though I didn’t eat my regular meals during that time (I ate less for breakfast and didn’t eat lunch), which adds something like 900 calories.

2750 + 900 = 3650 expended.

for a net of:

3650 – 1400 = 2250.

So, where did the extra come from? It came from my fat stores. I’ve been doing some reading on this – Chris Carmichael’s “Food for Fitness” (very good, by the way) and a few research studies – and it turns out that fat transport can supply a lot of calories over a long period, under two conditions.

The first is that the system is trained. The second is that there’s sufficient glucose available to keep things going. To simplify, you need a constant supply of glucose to keep your metabolism going and your brain happy – if you get low on glucose, your brain will hoard it and you performance will tank, with the dreaded “Bonk”.

Making another assumption – that I was getting approximately 80% of my energy from fat and 20% from carbohydrate, you’d expect that of the 3650 calories, 2920 came from fat and 730 from carbohydrates (okay, there’s some in there from protein, but not a large proportion).

With the exception of the Clif bars, most of what I ate is at least 75% carbohydrate, so there’s plenty of carbs to keep me going, assumming that it can get into the bloodstream quickly enough. That’s where the Accelerade helps.

At this point, I should note that I’m not an expert at these things *and* that I’ve made a ton of simplifications along the way. For example, the brain uses a fair amount of carbohydrate, but that use can be supplied by conversion from fat to carbohydrate, so the carbs that I took in didn’t need to support that part of my base metabolism, and were therefore free to be used towards the exercise.



Flying Wheels Summer Century 2005

June 19, 2005 at 9:41 pm

Yesterday, I participated in my first Century of the year, a hilly 100-miler (hence the term “century”) known as the Flying Wheels Summer Century (alternately known as the “Screamin Thighs Summer Century”).

In last year’s edition, I rode by myself and finished in 6:49:22, averaging about 15 MPH.

This year, I was hoping to do better. Though I had only broken the 50 mile once this year, I had been riding hard with some faster riders, I had a new bike (“the beauty”) that was nearly 10 pounds lighter than my last bike (the rain bike, aka “the beast”).

I did the 50 mile version with a group a week ago, and then rested my legs for the week. I prepared Friday night by getting about 3 hours of sleep and arose Saturday at 6 feeling groggy, dehydrated, and a bit queasy. The almond Clif bar and 16 oz of water I had for breakfast did nothing to improve the situation, but at least I made it to the starting line with all my gear, including my shoes.

We ended up with a group of about 12 riders, and headed out. The first section of the ride (about an hour or so) takes you on two major climbs, and I wasn’t feeling much better at the first food stop. I drank a large chunk of my Accelerade, and we headed out in a paceline across the valley towards Duvall at a bit over 20 mph. I wheel-sucked mercilessly, as there was no way I was going to be doing a turn at the front the way I was feeling. By the time we got to the third climb at Stillwater hill, I was feeling okay, and I spun up it in my lowest gear (yes, buying the triple chainring was a good choice, even though it’s not quite as manly) with one of my friends. We worked our way past a detour, and then flew back downhill on the descent down Cherry Valley Road. The 19th century pavement combined with the high redneck quotient make this an exciting section, especially when there are a hundred riders on it and you’re trying to pass them, but it was better than last year, and we made it to the next water stop.

At that point, I decided I might just live, so I at half a Clif bar and mixed another bottle of Acclerade. We headed north on High Bridge Road, which is when things started to deteriorate a bit.

There’s an interesting feature of group rides. If you’ve watched racing on TV, you’ll know that the big breaks happen on the climbs, so you might expect that the climbs would break apart the groups, but nearly all groups have a “regroup at the top” policy where you wait until the group gets together. If you don’t do this, you end up without a group, as a good hill spread out the group pretty well.

It’s rolling hills that break up a group, mostly because of the way that pacelines work. The lead rider is trying to maintain a steady pace, warn the group of hazards/turns/stops, and not puke his lungs out. The second rider has an easy job – he drafts closely behind the first rider usually at around half a wheel diameter. Because the lead rider’s speed isn’t constant, he needs to adjust his speed up and down,  but that’s pretty easy to do – you pedal a bit harder, or soft pedal. It’s a cushy place to be, except that you know that in a short period of time – somewhere between 2-10 minutes – the lead rider will peel off, and you’ll put in your time.

The third rider has a harder job, as he keys off of the second rider, so instead of the small speed variations of the leader, he has the larger variations of the second rider to work with.

And so on, back through the paceline. As you get farther back, you have to make harder efforts to stay on the wheel of the rider in front of you, and you also have to be more careful not to hit the person in front of you. Ideally, you never use brakes in a paceline, but realistically, if pulling a bit to the side to slow you down (from the wind) isn’t enough, you sometimes have to feather your brakes.

Obviously, the longer the paceline, the harder it is to stay one, and we had 12 people at that point. If there’s a short climb, and your leader doesn’t drop the pace a little at the top, you’ll break off 3 or 4 people on the back. They then need to regroup and try to get back to the lead group, but 1) it’s 4 people vs 8 people at that point and 2) a couple of those people likely just finished their turn at the front.

That happened twice on the hilly part to Snohomish, as there were a few people pushing the pace (ie 23-24 mph). After the second break, our group of 3 or 4 decided not to bother chasing, and took a slightly more sedate pace into Snohomish. I pulled a section at about 20-21MPH, though it was near the airport and my wireless computer couldn’t decide whether my speed was 20, 45, or 67. We picked up a couple more people in Snohomish, and went about 20-22 into Monroe, which is a pretty good speed as it’s very flat.

This put us just a hair over halfway through the ride, and with the exception of the ominous “it’s going to rain really hard very soon” raindrops, we were doing fairly well. We took a 15 minute break, I made my last bottle of Accelerade, and we headed out. The first part of this section is flat, and we cruised at around 21MPH. Steven (one of the organizers of the group) took a turn, I took a second turn on the flat part, and then as I pulled off the front as we came to a short hill, one of the fast guys came to the front, sped things up, and the group rode both Steven and I off the back, leaving us to ride by ourselves to the next rest stop.

We were not amused.

It’s not that we were ridden off the back of the group. I don’t begrudge the fast guys their speed, and I know what it’s like to be with a group that’s riding slower than you want to. It happens to me all the time… Well, occaisionally… Okay, I read about it in a book.

So guys pulling fast at the front is not a problem. What is a problem is that there were a few people who were curiously absent from the front of the group for the whole ride. Because of the distances and times between stops, if you grab the 7th or 8th position consistently and put your effort in on hills to maintain that position, you can hang back and not do any of the hard work.

This behavior may be acceptable, depending on the group. If you have one or two riders who aren’t up to speed that day but you want to keep them in the group, the rest of the riders may not mind carrying them along. I’ve certainly done that on some of our Wednesday rides.

The underlying problem was the size of the group. If we could split our group in half, the fast guys could ride at a speed they were comfortable with, and we could ride a bit slower. Steven and I decided that it made sense to split the group, and we told people that we thought it was a good idea to break into smaller groups, and that the two of us were going to ride a bit slower.

We’d hoped that a few others would join us, but nobody did, so we headed off towards Fall City at around 19MPH, a bit faster when Steven was on the front, a bit slower when I was there. Before the final hill in Fall City, we met up with three more guys who’d decided the fast group was a bit too fast for their liking (without Steven and I keeping the speed down at the front, they’d picked up their pace), and we headed up the hill, hit the last rest stop, and ended up with 4 of us for the spin back into Redmond along East Lake Sammamish.

A great ride overall. Given that my goal was to finish in around 6 hours and I felt so bad at the beginning, a great day.


Distance:            100 miles
Time:                  5:34
Average Speed:  18 MPH
Elevation Gain:    5375 feet

The elevation gain at Flying Wheels is usually given as 3200′ of vertical. One of our group had a GPS with him, and he came up with 5400′ of vertical. I did the route in Topo USA, and came up with 5375′ for the course.

My guess is that this is the difference between measuring elevation gain with a barometric altimeter and a GPS or topo mapping program. My guess is that the barometric sensor is doing a lot more data smoothing, and is missing a lot of the little ups and downs.


1.5 Clif bars
56 oz Accelerade
1 bagel
1 newton
33 pretzels
70(ish) oz water

The switch to Accelerade has been a huge success. It really doesn’t have that many calories – only about 10 per ounce – but they are very easily accessible. The Accelerade gave me enough glucose to keep going, and the rest of the energy came from my fat stores.


Bicycle Climbs of Seattle, Eastside Edition

June 16, 2005 at 12:24 pm
Spent a bit of time polishing up my google maps application last night, and it’s ready for public showing.
This is based on an idea I’ve had percolating away in the back of my mind for a few months now…
That takes you to a google map which shows a fair number of climbs around these parts. Click on a climb, and you’ll get a popup with some data about the climb, and click on the name of the climb to go to the detail page.
I feel fairly confident that the length and elevation gain data is correct, and therefore the average gradient is likely to be pretty good as well. The maximum gradient – well, I’ve taken that from the steepest parts of the gradient plot, but there is certainly some chance for error there. Not only do the roads on Topo USA not conform to actual contours (which definitely messes up the gradient plot on any climb with switchbacks), their topo data may also not take into account that grading that takes place during road construction.
I’m looking for:
  • General comments and suggestions
  • New climbs to add, both on the eastside and in Seattle and elsewhere
  • Better data for maximum gradients
  • Descriptions for the climbs.
  • Rankings for the climbs. I currently have green, yellow, and red. I’m going to add something beyond red for climbs like the zoo, but if you think I’m off on the relative ranking of climbs, let me know.
(Technology stuff)
This was originally going to be all generated on the fly, but I’d forgotten how much of a pain it is to work with a database on a web server. So, the data lives in a database on my machine, and there are a set of C# scripts that generate both the detail pages and the xml to drive the google maps page (yes, I know, how 1998 of me). The maps and gradient plots are hand-extracted from Topo USA.