Kids, Don't Try This At Home

As many of my readers and patients know, I am trying to qualify for Paris-Brest-Paris, a 1,200-kilometer endurance ride held every 4 years. Although not a race, it is a timed event, and you have to reach all of the checkpoints by a specified time to avoid being disqualified. Qualifications start this year, as I have to do a full series of endurance rides (called "brevets"): 200k, 300k, 400k and 600k. If I complete all of them successfully, I get to repeat the process next year; and if I complete all of those successfully, I will be able to ride in Paris-Brest-Paris.

So I'm thinking to myself that in a few weeks, I start the brevet series with a nice 200k, and maybe, just maybe, I ought to see if I can do a major chunk of that, like 100 miles. I have been training, though not as diligently as I should.

On Sunday, with no other obligations pending, I took off for a 101-mile loop leaving from Granby CT, going north to Northampton, then looping around through Amherst and Granby MA and eventually back to Granby, CT.

And a beautiful day it was. I passed more cows than you can count, went through beautiful, quaint, New Englandy towns, enjoyed the features of one of my all-time favorite college towns, Amherst, and in general just took pleasure in a fine ride on a beautiful day. The temperature was 72F by 11 a.m. and the few cirrus clouds called it quits by lunchtime.

One of the key tricks to any endurance exercise, whether it is a marathon, a triathlon, or brevet, is managing your fuel and water. You have to constantly plan ahead, because if you wait to drink until you are thirsty, or wait to eat until you are hungry, it is already too late. In addition, the gastrointestinal tract tends to shut down under the stress of endurance exercise, and you may never get hungry. The only way you'll know that you are out of fuel is when your legs turn to lead and your mood plummets.

There are a lot of complex rules governing your body's management of glucose, the basic energy molecule, and there are a lot of nuances to controlling blood sugar levels during exercise. But the general rule of thumb is to have some water every 15 minutes and something to eat every 45.

That's a rule that I generally follow. On Sunday's trip, I also took a longer stop at mile 63 where I had a "deli delight" lunch -- a submarine sandwich, a bag of chips, and some Oreo cookies.

After that, I hopped back on the bike for the final leg of the trip. This was a fun part, because I had finally hit a few hills -- more than rollers, but not what I call a hill around my house. I was gratified to see that, although the legs were paining me a bit, I still had the juice to attack the hills, albeit somewhat anemically.

I was taking the perimeter road around Bradley Airport when I realized, at mile 93, that I had the barest shot of breaking 7 hours for a century. For many cyclists, there's nothing special about a 7-hour century. It's a good pace, that's all. But I'm a slow guy, always have been a slow guy and always will be a slow guy. And among the Berkshires and their foothills, I've never come close to breaking 7 hours.

So...I take a deep breath and put the hammer down. For the next 7 miles, I sprint absolutely as fast as I can. At parts, I know I'm running at my maximum heart rate, because I was getting the tunnel vision and the eyes-rolling-to-the-back-of your head symptoms that have always happened when I'm doing a maximum heart rate measurement.

As I hit the last half mile, I come to a bend. And I look at the clock, and think to myself, "If this is downhill, I've got it made. Uphill, I'm toast."

I round the bend, and there it is: Uphill. So I let out a yell that would tell God Himself to get out of the way, and put absolutely everything I've ever owned into that last half mile. I mean, I ride like Cerebrus' meaner brother was chasing me.

And through my ever-narrowing vision and feeling like I'm about to pass out, I see the clock tick over to 7 hours at the exact same time the odometer clicks to 100.00

It's over. I didn't break 7 hours, but if I realized my opportunity only one hundredth of a mile beforehand, I would have. Still, hitting 7 on the nose is good enough for me. It's still a personal best, and I'm looking at setting a lot of records for myself this summer.

I slow from a gallop to a walk for the remaining 4 miles to the parking lot, and as I make the final turn the wrong way, I realize something might be wrong. I get back to the truck, park the bike, and take stock. My hands are shaking; I feel very dizzy; and I'm slurring my words like Sean O'Malley on St. Patrick's Day.

The problem? My blood sugar had plummeted. I react as fast as I am able, by downing a sugary soda and a concentrated sugar paste. It took a good 15 minutes before I was in control of my faculties again.

In any endurance sport, after the first 60-90 minutes, you have used up all of the energy reserves stored as glycogen in your body. From that point on, as I mentioned earlier, you must constantly add fuel, otherwise you will get into trouble -- as what nearly happened to me.

While I was balancing energy outflow with intake, my nutrition plan did not take into account that impromptu sprint for the last 7 miles. The massive increase in energy use forced my blood sugar levels to dangerously low levels. And, since the body's most energy-consumptive organ is the brain, the symptoms are often neurological -- thus the befuddled direction-finding, the shaking hands, the slurred speech, even while I was able to maintain muscle activity on the bike.

More and more, I am finding that I can help endurance athletes prepare their bodies for the onslaught of their competitive events by working with their diets beforehand so they can achieve their personal best. Just as any athlete needs a coach for their physical training, a nutrition coach is also a necessity.

Barefoot Running

A reader brought to my attention the growing trend of barefoot running, given fuel recently by this study:

Foot strike patterns and collision forces in habitually barefoot versus shod runners.

Lieberman DE, Venkadesan M, Werbel WA, Daoud AI, D'Andrea S, Davis IS, Mang'eni RO, Pitsiladis Y.

Department of Human Evolutionary Biology, 11 Divinity Avenue, Harvard University, Cambridge, Massachusetts 02138, USA. danlieb@fas.harvard.edu

Comment in:

• Nature. 2010 Jan 28;463(7280):433-4.

Humans have engaged in endurance running for millions of years, but the modern running shoe was not invented until the 1970s. For most of human evolutionary history, runners were either barefoot or wore minimal footwear such as sandals or moccasins with smaller heels and little cushioning relative to modern running shoes. We wondered how runners coped with the impact caused by the foot colliding with the ground before the invention of the modern shoe. Here we show that habitually barefoot endurance runners often land on the fore-foot (fore-foot strike) before bringing down the heel, but they sometimes land with a flat foot (mid-foot strike) or, less often, on the heel (rear-foot strike). In contrast, habitually shod runners mostly rear-foot strike, facilitated by the elevated and cushioned heel of the modern running shoe. Kinematic and kinetic analyses show that even on hard surfaces, barefoot runners who fore-foot strike generate smaller collision forces than shod rear-foot strikers. This difference results primarily from a more plantarflexed foot at landing and more ankle compliance during impact, decreasing the effective mass of the body that collides with the ground. Fore-foot- and mid-foot-strike gaits were probably more common when humans ran barefoot or in minimal shoes, and may protect the feet and lower limbs from some of the impact-related injuries now experienced by a high percentage of runners.

It's an interesting idea, and certainly has its appeal, falling in line with other fitness trends such as functional strength training and the naked warrior concept. I've known people who have been running barefoot since the mid-90s.

But I suspect the faddishness of the trend, and I see some real problems with the research. The first is that it was not until last fall, with the Wolf study, that a decent examination of the consistency of lower extremity kinematics was even performed (to my knowledge, at least). Without that base consistency data, drawing conclusions from a comparison of shod versus barefoot kinematics is perilous. How do we know that the data from the Lieberman study (and others) even falls outside the range of normal variation? The fact is, we do not. So to to make conclusions about technique from such studies is rash.

While the research does show some force reduction at the joints, from that data the researchers are *presuming* a reduction of injury. There are not any studies which actually show a reduction of injury, and it is quite possible that none will be found. Lieberman admits this limitation in his study. What is most probable is that barefoot running may tend to reduce the risk of certain types of injuries, while increasing the risk of others, and as I note below, the benefits are likely to vary widely based on individual biomechanics. There truly is no such thing as a free lunch.

Similarly, performance has not been evaluated. The argument held forth thus far is the "Ethiopian runners do it and they are the best," which is an argument beset with obvious problems, from cardiopulmonary functioning to femorotibial ratios. Until I see some good studies, I am inclined to dismiss barefoot running performance claims.

Interestingly, the kinematics of shoeless running point to the fact that, in all likelihood, the runners who do benefit most from shoeless running are those that are free of foot dysfunction in the first place. Which makes sense.

It is important to note that the foot scans I'm providing are not with the intent to provide a rationale to fit every athlete with orthotics, but more to detect those individuals whose foot dysfunction or pathology tends to increase their risk of injury or hinder their performance. For such individuals, there is absolutely no data to suggest that they would benefit from barefoot running and a wealth of research to suggest that custom orthotics would be beneficial.

I'm not a one-size-fits all kind of doctor, and I may happily recommend seemingly contradictory advice to two different patients with the same (apparent) problem, because I think that any protocol needs to account for the huge individual variability in physiology and biomechanics. It is one of the core ingredients missing in most of mainstream medicine.

So I'm not going to utterly dismiss barefoot running out of hand, because it may have some genuine utility for some people. But the majority of runners, I suspect, will continue to benefit from a well-made shoe and proper foot support.