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Research has confirmed that people’s physiological responses to exercise vary wildly. Now a new genetic test promises to tell you whether you are likely to benefit aerobically from exercise. The science behind the test is promising, but is this information any of us really needs to know?
Gretchen Reynolds on the science of fitness.
The new test, which is being sold by a British company called XRGenomics, is available to anyone through the company’s Web site and involves rubbing inside your cheek with a supplied swab and returning the tissue sample to the company. Results are then available within a few weeks. It is based on a body of research led by James Timmons, a professor of systems biology at Loughborough University in England, and colleagues at the Pennington Biomedical Research Center in Louisiana and other institutions.
That original research, published in a landmark 2010 study, looked into the genetics of why some people respond to endurance exercise so robustly, while others do not. Some lucky men and women take up jogging, for example, and quickly become much more aerobically fit. Others complete the same program and develop little if any additional endurance, as measured by increases in their VO12 max, or their body’s ability to consume and distribute oxygen to laboring muscles.
For the 2010 study, Dr. Timmons and his colleagues genotyped muscle tissue from several groups of volunteers who had completed 6 to 20 weeks of endurance training. They found that about 30 variations in how genes were expressed had a significant effect on how fit people became. The new test looks for those genetic markers in people’s DNA.
“The idea is to help people to understand why” they might be progressing more slowly in an exercise program than their training partners are, says Dr. Timmons, one of the founders of XRGenomics.
After he appeared on a BBC science program last year, in the course of which the host was revealed to be a “low” responder, according to his gene profile, Dr. Timmons was inundated with e-mails and calls requesting the test, he says. At that point, he and several colleagues filed a patent (still pending) for the gene markers and brought the test to market.
It joins other, less-sophisticated exercise-related gene test kits already available over the counter. These tests, which are not monitored by the Food and Drug Administration, typically rely on a single gene marker and claim to be able to predict whether you — or your child — will have success as a distance runner, say, or as a power-based athlete, like a sprinter.
Their actual predictive value, based on the best currently available genetic science, “is approximately zero,” says Claude Bouchard, a professor of genetics at Pennington, who was the senior author of the 2010 study with Dr. Timmons, but has no involvement with XRGenomics. (He is a paid consultant for another company, Pathway Genomics, that offers gene tests only through physicians.)
The new test is almost certainly more reliable, with “a much stronger scientific basis than any of the previous exercise-related DNA test kits,” says Tuomo Rankinen, a professor of genetics at Pennington, who, like Dr. Bouchard, was an author of the original gene study but has no involvement with XRGenomics. But, he adds, it relies on VO12 max, just one measure of how someone responds to exercise, so it has severe limits.
The new test will not tell you, for example, how exercise might affect your blood pressure over the long haul, Dr. Rankinen says, or whether your insulin sensitivity might change, or whether you’ll lose weight. The genetic markers related to these health responses to exercise are quite different from those related to VO12 max, he says.
In other words, the scientific understanding of how our DNA affects our overall bodily response to exercise is in its infancy.
Which does not mean that anyone curious — and deep-pocketed — enough to take the test should refrain from doing so. At present the basic test kit costs about $318 (199 British pounds) for genotyping and a brief accompanying report. For about $478, you receive a more extensive explanation of the findings, along with customized exercise recommendations from the company’s scientific advisory board. The report might suggest, Dr. Timmons says, that if you are a “low” responder to endurance exercise, you should concentrate on resistance training or otherwise refocus your training.
“What we hope,” he says, is that the test and report “will encourage people to keep exercising” who might otherwise have quit when running or swimming didn’t make them more fit.
On the other hand, some people might look on the news that they are a “low” responder to endurance training as a license to quit working out altogether, he acknowledges.
But Dr. Bouchard says that that would be the worst message to take from any gene testing. “This is a good test, as far as it goes,” he says. But genes will never be destiny.
In the original 2010 gene study, the authors concluded that the gene profile they’d uncovered accounted for at least 23 percent of the variation in how people responded to endurance training, which, in genetic terms, is a hefty contribution. That leaves perhaps 77 percent of how you respond to exercise consciously up to you.
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Thor Swift
Getting children to be more physically active seems as if it should be so simple. Just enroll them in classes and programs during school or afterward that are filled with games, sports and other activities.
But an important new review of the outcomes of a wide range of different physical activity interventions for young people finds that the programs almost never increase overall daily physical activity. The youngsters run around during the intervention period, then remain stubbornly sedentary during the rest of the day.
For the review, which was published last week in the British medical journal BMJ, researchers from the Peninsula College of Medicine and Dentistry in England collected data from 30 studies related to exercise interventions in children that had been published worldwide between January 1990 and March 2012.
To be included in the review, the studies had to have involved children younger than 16, lasted for at least four weeks, and reported objectively measured levels of physical fitness, like wearing motion sensors that tracked how much they moved, not just during the exercise classes but throughout the rest of the day. The studies included an American program in which elementary school-age students were led through a 90-minute session of vigorous running and playing after school, three times a week. Another program involved Scottish preschool youngsters and 30 minutes of moderate physical playtime during school hours, three times a week.
In each case, the investigators had expected that the programs would increase the children’s overall daily physical activity.
That didn’t happen, as the review’s authors found when they carefully parsed outcomes. The American students, for instance, increased their overall daily physical activity by about five minutes per day. But only during the first few weeks of the program; by the end, their overall daily physical activity had returned to about where it had been before the program began. The wee Scottish participants actually became less physically active over all on the days when they had the 30-minute play sessions.
The review authors found similar results for the rest of the studies that they perused. In general, well-designed, well-implemented and obviously very well-meaning physical activity interventions, including ones lasting for up to 90 minutes, added at best about four minutes of additional walking or running to most youngsters’ overall daily physical activity levels.
The programs “just didn’t work,” at least in terms of getting young people to move more, said Brad Metcalf, a research fellow and medical statistician at Peninsula College, who led the review.
Why the programs, no matter their length, intensity or content, led to so little additional daily activity is hard to understand, Dr. Metcalf said, although he and his co-authors suspect that many children unconsciously compensate for the energy expended during structured activity sessions by plopping themselves in front of a television or otherwise being extra sedentary afterward. It is also possible, he said, that on a practical level, the new sessions, especially those taking place after school, simply replace time that the youngsters already devoted to running around, so the overall additive benefit of the programs was nil.
But the broader and more pressing question that the new review raises is, as the title of an accompanying editorial asks, “Are interventions to promote physical activity in children a waste of time?”
Thankfully, the editorial’s authors answer with an immediate and emphatic “no.” If existing exercise programs aren’t working, finding new approaches that do work is essential, they say.
They point out that active children are much more likely to be active adults and that physically active children also are far less likely to be overweight. A convincing, if separate body of scientific evidence has shown that the most physically active and fit children are generally the least heavy.
So if structured classes and programs are not getting children to move more, what, if anything, can be done to increase physical activity in the young? “It’s a really difficult problem,” said Frank Booth, a professor of physiology at the University of Missouri-Columbia, who was not involved with the review.
Determining the most effective placement of classes and programs, so that they don’t substitute for time already spent running around and instead augment it, would help, he said.
But a more vital element, he said, “involves mothers and fathers,” who can encourage children to leave the couch, subverting their drive to compensate for energy expended earlier by sitting now.
A welcoming setting may also be key, the authors of the accompanying editorial wrote, pointing to a 2011 study of same-sex twins, ages 9 to 11. In that study, the most important determinant of how much the youngsters moved — or didn’t — was their local built environment. Children with more opportunities to be outside, in a safe, well-designed space, were more likely to be outside, romping.
But none of these suggestions will be easy to put in place, Dr. Booth said, or inexpensive, and all will require scientific validation. No one expected, after all, that well-designed exercise interventions for children would prove to be so ineffective.
Ultimately, he continued, the best use of resources in this field may be to direct them toward unearthing the roots of childhood inactivity. “Kids naturally love to run around and play,” Dr. Booth said. “But they’re just not doing it as much now. And we don’t know why. So what we really need to understand is, what’s happening to our kids that makes them quit wanting to play?”
Gretchen Reynolds on the science of fitness.
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Team sports don’t hold much appeal for me, with the notable exception of volleyball. I don’t know exactly why that is, but it may have something to do with the lack of violence in the way the game is played. There’s no tackling, tripping, checking, or jostling between players on opposing teams, just the graceful lobbing or purposeful spiking of the ball over the net. Other sports, such as tennis and badminton, have the same appeal, but I like the aspect of team cooperation that is so essential to a good volley.
I once played on a volleyball team and enjoyed it greatly; that is, except for the bruises on my forearms caused by excessive bumping, the aches in my jammed fingers from setting the ball, and the scrapes on my knees from my unsuccessful attempts to keep the ball off the floor. I’ve always thought I’d like to try beach volleyball for that reason, since sand seems much more forgiving than concrete, and the mood is often more casual than serious.
However, I’ve recently found yet another option that could fulfill my need for fun, safety, and team cooperation. The new sport of bossaball is played on a court consisting of inflatable panels, trampolines, and a net, and combines aspects of volleyball, soccer (or football, as it’s known outside North America), gymnastics, and the Brazilian martial art of capoeira.
Blame it on the Bossaball-a
Contrary to what its name might suggest, bossaball was developed in Spain and Belgium, although it takes inspiration from Brazilian music, beach culture, and sport. The word bossa
, which is sometimes translated as gusto, style, flair, or attitude in Portuguese, is commonly associated with Bossa Nova, a samba-influenced type of music first pioneered by Brazilian musicians Antônio Carlos Jobim, Vin?cius de Moraes, and Jo?o Gilberto in the late 1950s.
The name bossaball, therefore, is fitting since music is a major component of how the game is played. In fact, the person overseeing the game is called the “samba referee,” and not only makes calls, but serves as the Master of Ceremonies and provides musical accompaniment to the action going on with the help of a whistle, microphone, percussion instruments, and a DJ set.
The Girl from Trampolina
The basic goal in bossaball is to get the ball to touch the ground on your opponent’s side of the net, as in volleyball, and to win points based on where the ball lands. The most coveted target is the round trampoline directly in front of the net, which earns a team three points, and if the ball hits the inflatable panels around the trampoline, one point is scored. No points are scored if the ball lands on the rings around the trampoline, and the game continues after that.
Teams consist of three to five players, with one player stationed on the trampoline in the middle, and the other players flanking him or her. Eight touches are allowed on each side before the ball must go over the net; only one touch with the hands per player, and two if the player uses his head or feet instead. Teammates not on the trampoline work to position the ball so that the middle player can spike it over the net, either by hand or by executing a flip and kicking the ball to the other side.
Inflated Expectations
Watching the game in action on YouTube reminded me of how much fun I had as a kid jumping and doing flips on trampolines and bouncing around inside those inflatable play houses often found at amusement parks. The players dove, flipped, and jumped in cushioned comfort, and seemed to be having a great time. I felt an immediate urge to join in.
Unfortunately, the key component of the game, the inflatable court and trampolines, does not seem to be widely available outside Europe and possibly Brazil. I don’t know if there are any plans to bring bossaball to North America, but until that happens, I’ll have to settle for volleyball—and make sure I have a good supply of bandages and iodine before I head out on the court. —Morgen Jahnke
Thanks to reader Ronald Peavey for suggesting today’s topic!
The definitive source for Bossaball information is bossaball.com, where you can find contact information for court suppliers in Spain and Belgium, as well as photos, media links, and game specifics.
This YouTube clip features footage from a game between Brazilian and Spanish teams in January 2007.
There’s also a Bossaball article in the Wikipedia.
The photograph by Pedro Romero is licensed under the GNU Free Documentation License, version 1.2.
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