Field of Science


Muscle Memories

Let me tell you about one of the dumbest workouts I've ever seen.

No, it wasn't somebody doing sprints in Shape Ups. Last week I saw an oldish man in my building's workout room, wearing khakis and a plaid button-down (always a red flag). When I arrived, he was doing bicep curls with 3-pound weights, one in each hand. Aw, I thought, he has to use really light weights because he's older. And he's counting out loud because he can't remember how many reps he's done! (It was 20.)

Then he put down the 3-pound weights and picked up the 5-pounders, and did the same 20 bicep curls. Then the 8-pounders: 20 bicep curls. Sure enough, standing in front of my elliptical machine, he worked his way down the entire rack of free weights. Then he moved to the heavier weights on the other wall. "! Unh...two!" He grunted through sets of 20 bicep curls on increasingly giant dumbbells. Then suddenly he was holding a stretchy rubber cord with handles. He stepped on the cord with his right foot and stood with one end in each hand. Don't do it, I thought. He did a bicep curl. "One!" Twenty curls later, he switched feet.

The moral of this story--besides that I now know exactly how many pieces of equipment in our workout room can be used for a bicep curl--is that some workouts are obviously counterintuitive. Why waste your time on 3- and 5-pound weights when you can lift 25-pounders? (And how big do your biceps need to be if they're the only part of your body you're working out?) If you've ever exercised, you can feel that your body gets stronger only as you challenge it.

Muscle cells don't look quite like those textbook fried-egg cells, with a nice round yolk in the middle and a bunch of goo outside. Instead, they're very long fibers that can have many nuclei. When you exercise, your stressed-out muscle fibers absorb some of the little helper cells that live around them. Then the extra nuclei (it seems) help your muscle fibers grow thicker.

In a new study, Norwegian scientists made mice exercise a certain muscle for three weeks, and observed the extra nuclei--54% more than the mice started with--being added to the muscle fibers. After the nuclei started to increase, the muscle fibers increased in thickness.

The scientists worked another group of mice for two weeks and then severed the nerves connected to the muscle, forcing it to atrophy. They found that even though the muscle fibers shrank dramatically, the number of nuclei stayed essentially the same over the following two weeks. Even three months later, there were still extra nuclei in the muscle fibers.

This might be the reason, they say, why it's easier to gain muscle where you've had muscle before. Even if you haven't exercised in a long time, you're not starting from scratch because you might still have extra nuclei in your muscle fibers. The authors point out that three months is a pretty long time for a mouse, which only lives a couple of years. So who knows how long the effect might last in humans?

Athletes who are known to have used steroids in the past are still allowed to compete--but what if it turns out that steroids give muscles a boost that lasts for many years? Even if previously bulked-up steroid users seem to have returned to normal, what if their muscles retain extra strength or efficiency? "The benefits of using steroids might be permanent," the authors say. Should everyone who's ever used steroids be banned for life?

The authors also suggest that by "filling up" muscles with nuclei earlier in life, people could prevent some of the weakness that comes with old age. Once people are older, it's much harder for them to build muscle mass--no matter how many bicep curls they do.

Do Shape Ups Measure Up?

I've been skeptical of these shoes from the first time I saw them, but I think I was biased by the advertising. You know those TV ads where the woman is bending over while the camera zooms in on her booty shorts? And then you find out it's selling shoes that are supposed to make you skinny? It's like every stereotypical women's marketing ploy rolled into one.

But I guess the idea is feasible. It's like standing on one of those balance balls at the gym. And those are supposed to be good for abs or something, right? So the idea is that by making the bottom of your shoe unstable, you make all of your muscles work harder all the time, thereby burning calories, toning muscles, and earning your booty shorts.

If you want to spend $125 on a walking shoe that makes it harder to walk, that's your prerogative. But inquiring minds want to know: Do the shoes really work?

Let's start with the official shoe sites. They all offer some sort of sciencey discussions of why their shoes work. The most outrageously priced of the unstable shoes, coming in at around $250, are the MBTs. (The acronym is short for Masai Barefoot Technology, a confusing name for a shoe that puts about an inch and a half of cushioning between your foot and the ground.) They have an "Academy" that they pay to conduct their research. As they explain in a sentence I can only hope was translated from another language, "Optimisation of the effectiveness of MBT is therefore supported by science."

MBT has an extensive list of studies performed by their "Academy." Most of them have to do with posture, back pain, and knee pain, but I'm interested in whether the shoes do the job most women presumably buy them for: exercise without exercising. In one study, the shoe scientists found that their shoes did increase oxygen use and heart rate--in subjects who stood still for six minutes at a time. When walking or running, people weren't working any harder with MBTs than with regular shoes.

Reebok, meanwhile, offers a shoe called Easy Tone. I had a harder time finding the commissioned studies for this shoe, though their site does allude to "research" and testing "in the lab." (I watched the movie called "Experience Easy Tone" thinking it would explain the sciencey ideas behind the shoe, but instead it was 54 seconds of the bottom half of a woman walking through a city in underwear and sneakers while a soundtrack said "sexy sexy.")

Reebok relies mostly on testimonials: "Easy Tone shoes make me feel like I have a tight tush," says Hannah. "I can FEEL them working!!" says Sara. Perrine from France adds, "These shoes make me WANT to walk more."

So much for Reebok. On to Skechers Shape Ups. The four studies they summarize on their site have a pretty specific conclusion: that the shoes "increase muscle activity and energy consumption over standard fitness shoes!" (Exclamation point theirs.)

In the largest of the Skechers studies, 80 men and women followed an 8-week walking course. The results, which are not described as statistically significant, include 2.5 pounds more weight loss than the control (regular shoes) group; 1.3% body fat lost (compared to 0.5%); and a vague 114% "improvement" in muscles (compared to 68%). Another study did not have a control group, while a third study gives conclusions without explaining what it did. Their final study was maybe the most interesting: It measured activity in various muscle groups (calf, buttocks, back, thigh) and found that the muscles were working harder with the Shape Ups--but this effect was mostly noticeable at a pace of 3 km/hour. That's 1.8 miles an hour. If you can put on bouncy sneakers and maintain a pace that slow, you are a more patient person than I am.

Finally, here's a study done by the American Council on Exercise, a nonprofit group not paid by any of the shoe companies. They put people on treadmills in all three kinds of unstable shoes and measured their exercise response (how hard they were working) as well as the activation of various muscle groups. The results? Nada. University of Wisconisn, La Crosse, researcher John Porcari says, "Don't buy these shoes because of the claims that you're going to tone your butt more or burn more calories. That's absolutely wrong."

What about the people who claim they really feel like they're working harder? "If you wear any sort of abnormal shoes...your muscles are going to get sore," Porcari says. "Is that going to translate into toning your butt, hamstrings and calves? Nope. Your body is just going to get used to it."

It's worth noting that this study used "physically active" female subjects. Maybe people whose regular level of activity is lower would experience more muscle activation when they started using the shoes--though that's not to say they wouldn't adapt over time.

If buying springy shoes gets people excited about walking more, I can't object too much. But let's be honest about what people are actually paying for. And if I really wanted "barefoot technology," I would try those Vibrams. After reading, and very much enjoying, the book Born to Run, I was convinced that these shoes are a good idea. (For running, that is. If you want to wear them to the grocery store, you're on your own.)

Not that I've bought a pair yet. I mean, they look ridiculous.

Optimism and Pessimism (a quiz)

Does everybody have a sharpened pencil?

1. A scary new type of drug-resistant bacteria has emerged in the UK. It appears to have come from____, where British people are traveling to _____.
a. Thailand/receive experimental stem cell treatments
b. America/take advantage of the weak dollar
c. Morocco/stay in Sex-and-the-City-2-themed hotels
d. India/have cosmetic surgery

2. Meanwhile, the World Health Organization has declared that the H1N1 (swine flu) pandemic is:
a. now peaking in the southern hemisphere
b. leading to a secondary pneumonia pandemic
c. just a lot of hype
d. over

3. If you're home with the flu, why not occupy yourself with a Rubik's cube? After 15 years of research, a programmer has determined that any Rubik's cube can be solved in just:
a. 80 moves
b. 50 moves
c. 20 moves
d. 15 moves

4. You already knew that orangutans are bad dieters, but did you know that they're also excellent at charades? This week, scientists published an overview of pantomimes they've seen orangutans act out. Which of the following was NOT included?
a. "I'd like a haircut."
b. "Your fly is open."
c. "Hurry up and open this coconut for me."
d. "Wipe that dirt off your face."

5. Earlier this year, Stephen Hawking made the surprising assertion that we shouldn't try to contact extraterrestrials, because intelligent aliens are probably mean. This week, in another bizarre blend of scientific optimism and pessimism, he said that:
a. If we can just avoid wiping ourselves out for another 200 years or so, humans will be able to survive by colonizing other planets.
b. HIV is going to solve the planet's overpopulation problem.
c. After global warming melts the ice caps completely, the ocean will be able to absorb a lot more carbon.
d. Humans will probably invent time travel shortly before our civilization collapses, thereby allowing someone to go back in time and warn us.

Answers are in the comments.

What Happens to Chatterboxes

Do you have videos of yourself at age seven? If so, you can probably see predictors of your current personality in your miniature self. A new study from a graduate student at the University of California, Riverside, says that certain personality traits in elementary schoolers are linked to certain other traits in middle-aged adults.

Psychology student Christopher Nave culled his data from a (very) long-term study that began in Hawaii in the 1960s. Elementary school teachers rated 2,400 students on dozens of personality traits: Is the student adaptable (copes easily and successfully with new and strange situations)? Is the student spiteful (deliberately does or says things that annoy or hurt others)?

Forty years later, researchers started hunting down these former students. So far, they've brought back about 450 of them. (Where did everyone go?) These good sports completed various tests and interviews, and out of those, Nave compared 144 who'd agreed to be videotaped and whose teachers had rated them on the same traits.

Based on their taped interviews and personality surveys, the adults were rated on 67 different traits. Many of the kid traits turned out to be strongly correlated with adult traits, and the researchers described four that were the most distinctive:

Verbal fluency, to psychologists, apparently means "chattiness" rather than "ability to speak one's native tongue." Adults who had been rated verbally fluent as kids were found to be smart, ambitious, controlling, and interested in intellectual matters. Kids who were adaptable became adults who are cheerful and sociable. Impulsive kids ("often acts before the appropriate moment; finds it difficult to hold back") were more likely, as adults, to be loud and energetic. And kids described as self-minimizing ("humble; never brags or shows off") were likely to seek reassurance and express guilty feelings as adults.

Maybe this is bad news for parents who were hoping they could teach their kid to be less impulsive. Or maybe it lets them off the hook a little. After all, if your kid's personality is already set at age six or seven, then there's not much you can do about it. (Half the kids in the analysis were in first or second grade, and half were in fifth or sixth grade. But these correlations were all found to be independent of grade level.)

Don't you wish you knew how your younger self measured up? It's like checking yesterday's horoscope to see if it came true. Or maybe you have a good sense of what you were like as a little kid. I remember my dad calling me a "chatterbox" in kind of a strained tone, so I'm guessing I talked a lot. According to the study, that means I'm less likely to seek advice now. Is that true? Do you think I should do something about it? Wait, no, don't tell me.

Pokey Pongo

Pity the Pongo who tries to go on a diet. Scientists announced this week that orangutans (their genus name is Pongo) have the slowest metabolism of almost any mammal. Pound for pound, they use less energy than mammals "including sedentary humans," as researchers noted with amazement.

How do you measure an orangutan's energy use? First, you feed it heavy water. Then you need to get it to pee in a cup. Luckily, captive orangutans at the Great Ape Trust in Iowa are pretty agreeable. "We walked around with some little paper Dixie cups and just held them under the ape and asked them if they would pee in the cup for us," says Washington University anthropologist Herman Pontzer.

Pontzer thinks orangutans have evolved super-slow metabolisms because, in the wild, they survive on fruit that can be scarce for much of the year. I'd be interested to know, though, how similar the captive orangutans really are to wild ones. The researchers say that the captive orangutans have "activity levels similar to orangutans in the wild." But surely there are other factors that could affect the metabolism of these animals, which are close relatives to humans. The types of activity they get, their stress levels, the regularity of their feeding, and their degree of interaction with other orangutans must all be different in captivity from in the wild. Just think of all the factors (according to your average women's interest magazine, anyway) that can affect human metabolism!

Even if the captive apes have a slower metabolism than their wild counterparts, it's still an impressive feat. The only mammal with a slower measured metabolism is the tree sloth. Like an orangutan, a sloth hangs out in trees a lot (often upside-down, in the case of the sloth) and has goofily long arms. Both animals are big dozers.

The sloth moves at an especially unhurried pace: somewhere around 2 meters per minute. So much for cardio!