Getting tested for VO2 max

Posted by Dave on March 1, 2012 | 7 Comments

VO2 max, as we have discussed before, is a key measurement of endurance running ability. There are several different procedures for measuring it, and yesterday I got to experience one of the most common methods first hand.

As I mentioned last year, VO2 max is simply the maximum volume of oxygen your body can take in:

the key to muscle performance is delivery of oxygenated blood to the muscles, and adequate fuel to produce energy. Oxygenated blood comes from the lungs, and is pumped by the heart, which is itself a muscle requiring its own supply of oxygenated blood.
VO2 max can be seen as the maximum performance of this system: the amount of oxygen that can be effectively delivered to the body in a given time period.

As your workout gets harder and harder, you can’t continue to breathe harder and harder; there is a fixed amount beyond which your body can’t keep up. That fixed limit is your VO2 max. All that’s needed to find it out is a way to measure oxygen intake, and a way to systematically make a workout harder.

I have volunteered to participate in a study of the effectiveness of a dietary supplement on running conducted by Appalachian State University, which has a research lab near my home. As a baseline, they measure body composition and VO2 max of all participants.

Their protocol was simple: I got on a treadmill, put on a face mask that would measure my air intake, and started walking. Initially the task was easy: about 1.7 miles per hour on a 10% grade. But every three minutes, the workout was made more difficult by upping the speed and the pitch of the slope. After 9 minutes I was jogging up a 16% grade. After 12 minutes the task seemed difficult, but doable. I felt like I could keep this up for some time. Here I am sweating it out on the treadmill:

Dave on the treadmill

So far, so good...

Then at 15 minutes the grade was increased to 20% and the speed was well over 5 miles per hour. Suddenly the task seemed nearly impossible. I kept it up for as long as I could — about a minute — but finally had to give up. This graph from my earlier article shows what was happening to my oxygen intake:

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The Basics: Preparing for the weather at a race

Posted by Dave on November 8, 2011 | 2 Comments

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It’s a week before the big race, you’ve started tapering and you can’t work out your anxiety with a nice, long run, so instead you begin to obsess over every detail. What if you get sick? What if you miss your flight or get caught in a traffic jam? What if it rains, or it’s too hot or cold?

Many of these things are out of your control, but you can prepare for the weather. Of course you’ll want to bring clothes for the range of possible weather conditions you’ll meet on the race course, but in most fall races in the U.S., conditions are actually fairly predictable: It will likely be quite chilly at the start of the race, and warm up as the race goes on.

If you’re running a marathon — especially a marquee race like New York or Boston, you may have to be at the starting area several hours before the race starts, when it will almost certainly be cold and dark. In addition to deciding what to wear at the race, you’ll need to bring clothes that will keep you warm while you wait around for the start.

Depending on the amenities at your race, there are several options. You could plan on wearing extra layers that you will drop of at the bag-check. If there is no bag check, then you could wear old clothes that you’re planning on getting rid of. Many runners wear a large plastic garbage bag before the race; this is especially useful if it’s raining. If you run lots of races, you could save the mylar blanket they give you at the end and use it to keep warm at the start of your next race. Just remember: At this point it’s best to overdress. For a marathon, you don’t want to waste too much energy walking around trying to stay warm. You’ll need to wear enough that you can sit down and still be warm.

I have generally found that I can remove my extra layers 20 to 30 minutes before the start of the race and strip down to whatever I’m planning to start the race in without getting too cold. Between the adrenaline of getting ready for a race and the warm bodies in the starting area, I stay warm enough.

But what about the race itself? It might be 40 degrees or cooler when you start, but by the finish the temperature could have risen to 60 degrees or warmer. When you are warmed up and running at race pace, you won’t need to wear as much as you start with.
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The Basics: Tweaking the GPS display for races

Posted by Dave on October 25, 2011 | 11 Comments

Last week at the 7 Bridges Marathon in Chattanooga, the unthinkable happened to my friend Todd: The battery died on his GPS trainer, 15 miles into the race. He had been running at near PR-pace, but without the feedback he was accustomed to, it was difficult for him to adjust, and he ended up missing a PR (personal record) by less than five minutes. He’s not sure he would have made it even with his GPS, but for many of us nowadays, running without GPS is like running blind, so it was bound to have a big effect.

Sure, there are mile-markers, but since Todd wasn’t wearing a wristwatch, he couldn’t time himself on each mile, so he really had no idea how fast he was going. It wasn’t always that way. Back in the 1980s when I ran my first 10K race, there was always a volunteer at each mile marker, calling out the times for that mile. That happens occasionally even today, but in my experience, more often than not, the times are wrong!

Yet even running with a fully-functional GPS can lead to its share of problems. It’s rare that the distance on my GPS matches the official distance of the course: In my case it’s usually a little longer than the official distance. Last weekend at the Bridges Half-Marathon, for example, my GPS measured the course at 13.34 miles (compared to 13.11 for a true half-marathon). If I had been shooting for a particular time — say, the 1:30 I would need to qualify for guaranteed entry to the New York Marathon in 2012, then that extra 0.23 miles would have added over a minute and a half to my time, and that could be the difference between success and failure.

Depending on what type of running you’re doing, there are many possible reasons a GPS can go wrong, but the fact of the matter is, it’s never going to be perfect. When you’re being timed in a race, what you care about is managing your pace over the official race distance.

So how, beyond making sure your battery has enough juice to make it to the end of the race, can you set your GPS device to match the official distance? It’s not an easy task. I usually have my primary GPS screen set up as follows:


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Adjusting for GPS elevation troubles

Posted by Dave on October 18, 2011 | 2 Comments

This weekend, on a whim, I decided to run the Bridges Half Marathon in Chattanooga. It turned out to be a pretty good whim, because I set a PR in the race!

As always, I like to take a look at my GPS record of the race afterwards to see if I might have done something differently to perform even better. But as I have long suspected, when I started to look at the elevation profile of the race, it seemed to completely botch up on bridges.

From a geological perspective, this bridge doesn't exist

Elevation data on the typical GPS trainers that runners use is notoriously bad. You can take a look at the raw GPS data from a run through Kansas and it will look like the Himalayas. To get around the problem, many running websites allow you to correct the elevations by cross-referencing against known databases maintained by NASA and the USGS.

The problem is, those databases don’t account for man-made objects. Run across a bridge, and from NASA’s perspective, you cruised across the river on your hovercraft, 100 feet below. But I hadn’t ever really come up with a clear illustration of the problem.

After uploading my data to the Garmin Connect website, here’s what my elevation profile looked like:

Garmin Connect Elevation Profile

I don’t remember the race being nearly that hilly! The last mile, for example, was completely downhill, and this profile includes a 60-foot climb! Similarly, miles 1, 5, and 7 include major dips that weren’t actually there; I was running across bridges at the time.

I decided to take a closer look at the elevation profile while simultaneously monitoring the satellite map of the course. Based on that observation, I was able to create a modified elevation profile that I think more closely reflects what I really ran:
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Are Boston qualifying standards unfair?

Posted by Dave on September 1, 2011 | 8 Comments

I’ve heard it mentioned several times that “women have it easier than men” when qualifying for the Boston Marathon. The argument usually goes something like this: Boston should be accepting the same proportion of talented male runers as female runners. But women get a 30-minute advantage in every age group, when the men’s world record in the marathon is only about 11 and a half minutes faster than the women’s record. It seems like a fairly compelling argument. If men are only 11 minutes faster, why should women get a 30-minute advantage?

As you probably know, the Boston Marathon is one of the few marathons that sets a minimum qualifying standard for most of the runners in the race. The only exceptions are people running for charity or who have affiliations with the sponsors of the race. These standards vary both by gender and age group, the idea being not just that men shouldn’t directly compete with women, but also that 50-year-old men shouldn’t be competing with 28-year-olds for starting spots.

But I’m not sure that the world-record argument makes sense when we’re talking about Boston qualifying standards. For the 2012 race, the fastest qualifying time, 3 hours and 10 minutes, is more than 50 percent slower than the world record. Clearly the typical qualifier doesn’t have much in common with a world-class athlete.

So I decided to do a different calculation. I took a sample of 8 popular marathons run in the past year, and then looked at what portion of men and women qualified for Boston in selected age groups. If women really have an unfair advantage, then a larger percentage of the women competing would qualify, right?

Below is the basic data:
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The Basics: Running safely in the dark

Posted by Dave on August 31, 2011 | 9 Comments

The Energizer Night Race (source: Competitor.com)

As the days begin to get shorter in the north and the school year wreaks havoc on running schedules, more and more runners are taking to the streets in the dark. I was surprised to realize last week that as the summer wanes, I once again need a headlamp for my regular 6 a.m. run with my local running club.

But as I run in to town on these mornings, I’m equally surprised to see many runners with no illumination at all, and even more who aren’t wearing reflective running gear, despite running along a busy thoroughfare. In the U.S. in 2008, over 4,000 pedestrians were killed in traffic accidents, and nearly half of those accidents occurred at night, despite the fact that there are significantly fewer cars and pedestrians during those hours.

If you run in the dark, you can increase your chances of avoiding an accident by wearing clothing that makes you more visible. Bright-colored clothing can help a little, but reflective running gear and lights improve your odds even more. Think of it this way: Car drivers at night are primarily looking out for other cars and traffic markings. All of these things are illuminated, have reflectors, or both. If you want to be seen, you need to look like the things car drivers are looking for, as this study I wrote up a few years ago for Cognitive Daily attests.

Take a look at the photo above and notice how easy it is to spot the runners, despite the fact that they are dressed in black! They have reflective print on their shirts and bright headlights: The reflectors are what matter, not the color of their outfits. With that in mind, here are some tips for running safely in the dark:
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Noakes on starting out in running

Posted by Dave on August 30, 2011 | 9 Comments

Lore of Running

930 pages of science!

This summer I’m reading Tim Noakes’ massive volume Lore of Running, bit by bit, then reporting the critical bits back to you. Last week I covered the ideal running drink: What Noakes believes is the best way to hydrate and fuel up during runs.

Leave it to Tim Noakes to save information for beginning runners until page 258 of his book! While the first part of the book covered the limits of elite runners, in this part he goes back to square one and explains what it takes for a beginner to get started in running.

So what is the best way to get started as a runner? Walking, says Noakes. If you are completely inactive, Noakes doesn’t recommend running at all until week 4 of your training program, and then only for 5 minutes on a single day. Noakes says that stress fractures are the most common injury of beginning runners, and the easiest way to get a stress fracture is to overtrain. Here’s Noakes’ table of the first 20 weeks of a training program designed to ease newbies into running:
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Mammals with bigger brains are better “athletes”

Posted by Dave on August 26, 2011 | 1 Comment

ResearchBlogging.orgHow do you measure a non-human animal’s VO2 max? Put it on a treadmill, just like you would with a human. What do you do with that information? If you’re David Raichlen and Adam Gordon, you use it to figure out if there’s any relationship between an animal’s ability as an “endurance athlete” and its brain size.

Perhaps a better question is why you would even imagine there was a relationship.

In fact, there is some reason to believe that brains might be linked to distance-running ability. One of the arguments put forth in Christopher McDougall’s book Born to Run is that humans have superior running ability because they used it to hunt other animals, simply by chasing them until they became exhausted. Humans are the smartest animals with the largest brains (relative to body size), so it’s possible that human intelligence and human running ability are related.

There’s a somewhat less far-fetched rationale for other animals: Aerobic exercise actually releases compounds that stimulate brain cell growth. So perhaps animals that are better at aerobic exercise naturally grow bigger brains. So Raichlen and Gordon found as much data as possible about as many different animals as possible—both VO2 max data and brain size data. In the end, they managed to find data for 29 different mammals including humans. So, is there any correlation between brain size and aerobic fitness? The graph below shows the results:
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What’s the minimum (and maximum) exercise to improve health?

Posted by Dave on August 25, 2011 | 12 Comments

ResearchBlogging.orgThe U.S. Department of Health and Human Services currently recommends that adults engage in exercise at least 150 minutes per week. They also say that more exercise is even better, but that also suggests that doing somewhat less than 150 minutes per week might be better than nothing.

If you’re an active runner, you might feel like 30 minutes per day, 5 days per week is the bare minimum you’d consider exercising, but if you’re doing no exercise at all, that much exercise might seem like an insurmountable hurdle. Back in the stone age when I was in my 20s and my kids were babies, I took a couple years off running. When I started back up again, it was very difficult for me to run even 10 minutes at a time. If a doctor had told me I needed to work out 30 minutes a day—especially if I had never exercised before—I might have given up after the first day!

Amazingly, few studies have systematically examined the benefits of exercising less than 150 minutes per week. That’s why a study published last week in Lancet has started to attract some attention. A Taiwanese team led by Chi Pang Wen tracked over 400,000 Taiwanese adults for 8 years, surveying them several times about physical activity levels and their health. Most importantly, their study allowed participants to indicate much lower amounts of exercise: as low as 75 minutes per week. Can just 15 minutes a day, 5 days a week, actually have a measurable impact on health?
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What’s the ideal running drink? Noakes weighs in

Posted by Dave on August 23, 2011 | 11 Comments

Lore of Running

930 pages of science!

There’s been a fair amount of discussion of hydration and dehydration on Science-Based Running, but it’s been focused on what to do to prevent serious problems, rather than how to optimize running performance. Let’s assume you’re not going to keel over from heat exhaustion or overhydration in a race. What should you consume before and during the race to maximize your performance?

This summer I’ve been reading Tim Noakes’ encyclopedic volume, Lore of Running and reporting what I’ve found back to you. This week I’m reading his chapter on temperature regulation during exercise. Noakes seems quite convinced that few runners are in danger of dehydration or heat exhaustion during races a half-marathon or longer. Indeed, they are in greater danger of overhydration.

For much of last century, runners were encouraged not to drink at all during races, and the rules often prohibited it. I still occasionally run with people who remember their coaches telling them not to drink during practice because that’s a sign of weakness. Modern elite athletes actually don’t appear to drink much during races either — if hydration is so important, why doesn’t Ryan White carry a CamelBak when he races?

The answer, according to Noakes, is that there is little evidence that runners should force themselves to drink if they’re not thirsty. That said, there’s plenty of evidence that some drinking is very important. The question is, how much, and what should you drink?

One piece of advice I’ve heard given to marathoners is that you should pre-hydrate as much as possible before a race: According to this line of reasoning, the more you pee, the better you’ll do, and make sure you’ve had enough that your urine stream is completely clear.

Noakes disagrees, saying that athletes should have their last drink two hours before race time, and even at that point, only drink enough so that their urine is lightly colored. For races longer than 10K, they should then carry about a half-liter of fluid to the starting line and drink it just before the gun. This is because water takes about two hours to get fully absorbed into your system. Any excess consumed in the meantime will simply be urinated out, along with sodium and other electrolytes your body needs.
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