Is Your Ab Workout Hurting Your Back?

 

The genesis of much of the ab work we do these days probably lies in the work done in an Australian physiotherapy lab during the mid-1990s. Researchers there, hoping to elucidate the underlying cause of back pain, attached electrodes to people’s midsections and directed them to rapidly raise and lower their arms, like the alarmist robot in “Lost in Space.”

In those with healthy backs, the scientists found, a deep abdominal muscle tensed several milliseconds before the arms rose. The brain apparently alerted the muscle, the transversus abdominis, to brace the spine in advance of movement. In those with back pain, however, the transversus abdominis didn’t fire early. The spine wasn’t ready for the flailing. It wobbled and ached. Perhaps, the researchers theorized, increasing abdominal strength could ease back pain. The lab worked with patients in pain to isolate and strengthen that particular deep muscle, in part by sucking in their guts during exercises. The results, though mixed, showed some promise against sore backs.

From that highly technical foray into rehabilitative medicine, a booming industry of fitness classes was born. “The idea leaked” into gyms and Pilates classes that core health was “all about the transversus abdominis,” Thomas Nesser, an associate professor of physical education at Indiana State University who has studied core fitness, told me recently. Personal trainers began directing clients to pull in their belly buttons during crunches on Swiss balls or to press their backs against the floor during sit-ups, deeply hollowing their stomachs, then curl up one spinal segment at a time. “People are now spending hours trying to strengthen” their deep ab muscles, Nesser said.

But there’s growing dissent among sports scientists about whether all of this attention to the deep abdominal muscles actually gives you a more powerful core and a stronger back and whether it’s even safe. A provocative article published in the The British Journal of Sports Medicine last year asserted that some of the key findings from the first Australian study of back pain might be wrong. Moreover, even if they were true for some people in pain, the results might not apply to the generally healthy and fit, whose trunk muscles weren’t misfiring in the first place.

“There’s so much mythology out there about the core,” maintains Stuart McGill, a highly regarded professor of spine biomechanics at the University of Waterloo in Canada and a back-pain clinician who has been crusading against ab exercises that require hollowing your belly. “The idea has reached trainers and through them the public that the core means only the abs. There’s no science behind that idea.” (McGill’s website is backfitpro.com.)

The “core” remains a somewhat nebulous concept; but most researchers consider it the corset of muscles and connective tissue that encircle and hold the spine in place. If your core is stable, your spine remains upright while your body swivels around it. But, McGill says, the muscles forming the core must be balanced to allow the spine to bear large loads. If you concentrate on strengthening only one set of muscles within the core, you can destabilize your spine by pulling it out of alignment. Think of the spine as a fishing rod supported by muscular guy wires. If all of the wires are tensed equally, the rod stays straight. “If you pull the wires closer to the spine,” McGill says, as you do when you pull in your stomach while trying to isolate the transversus abdominis, “what happens?” The rod buckles. So, too, he said, can your spine if you overly focus on the deep abdominal muscles. “In research at our lab,” he went on to say, “the amount of load that the spine can bear without injury was greatly reduced when subjects pulled in their belly buttons” during crunches and other exercises.

Instead, he suggests, a core exercise program should emphasize all of the major muscles that girdle the spine, including but not concentrating on the abs. Side plank (lie on your side and raise your upper body) and the “bird dog” (in which, from all fours, you raise an alternate arm and leg) exercise the important muscles embedded along the back and sides of the core. As for the abdominals, no sit-ups, McGill said; they place devastating loads on the disks. An approved crunch begins with you lying down, one knee bent, and hands positioned beneath your lower back for support. “Do not hollow your stomach or press your back against the floor,” McGill says. Gently lift your head and shoulders, hold briefly and relax back down. These three exercises, done regularly, McGill said, can provide well-rounded, thorough core stability. And they avoid the pitfalls of the all-abs core routine. “I see too many people,” McGill told me with a sigh, “who have six-pack abs and a ruined back.”

 

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Can You Get Fit in Six Minutes a Week?

 

A few years ago, researchers at the National Institute of Health and Nutrition in Japan put rats through a series of swim tests with surprising results. They had one group of rodents paddle in a small pool for six hours, this long workout broken into two sessions of three hours each. A second group of rats were made to stroke furiously through short, intense bouts of swimming, while carrying ballast to increase their workload. After 20 seconds, the weighted rats were scooped out of the water and allowed to rest for 10 seconds, before being placed back in the pool for another 20 seconds of exertion. The scientists had the rats repeat these brief, strenuous swims 14 times, for a total of about four-and-a-half minutes of swimming. Afterward, the researchers tested each rat’s muscle fibers and found that, as expected, the rats that had gone for the six-hour swim showed preliminary molecular changes that would increase endurance. But the second rodent group, which exercised for less than five minutes also showed the same molecular changes.

The potency of interval training is nothing new. Many athletes have been straining through interval sessions once or twice a week along with their regular workout for years. But what researchers have been looking at recently is whether humans, like that second group of rats, can increase endurance with only a few minutes of strenuous exercise, instead of hours? Could it be that most of us are spending more time than we need to trying to get fit?

The answer, a growing number of these sports scientists believe, may be yes.

“There was a time when the scientific literature suggested that the only way to achieve endurance was through endurance-type activities,” such as long runs or bike rides or, perhaps, six-hour swims, says Martin Gibala, PhD, chairman of the Department of Kinesiology at McMaster University in Ontario, Canada. But ongoing research from Gibala’s lab is turning that idea on its head. In one of the group’s recent studies, Gibala and his colleagues had a group of college students, who were healthy but not athletes, ride a stationary bike at a sustainable pace for between 90 and 120 minutes. Another set of students grunted through a series of short, strenuous intervals: 20 to 30 seconds of cycling at the highest intensity the riders could stand. After resting for four minutes, the students pedaled hard again for another 20 to 30 seconds, repeating the cycle four to six times (depending on how much each person could stand), “for a total of two to three minutes of very intense exercise per training session,” Gibala says.

Each of the two groups exercised three times a week. After two weeks, both groups showed almost identical increases in their endurance (as measured in a stationary bicycle time trial), even though the one group had exercised for six to nine minutes per week, and the other about five hours. Additionally, molecular changes that signal increased fitness were evident equally in both groups. “The number and size of the mitochondria within the muscles” of the students had increased significantly, Gibala says, a change that, before this work, had been associated almost exclusively with prolonged endurance training. Since mitochondria enable muscle cells to use oxygen to create energy, “changes in the volume of the mitochondria can have a big impact on endurance performance.” In other words, six minutes or so a week of hard exercise (plus the time spent warming up, cooling down, and resting between the bouts of intense work) had proven to be as good as multiple hours of working out for achieving fitness. The short, intense workouts aided in weight loss, too, although Gibala hadn’t been studying that effect. “The rate of energy expenditure remains higher longer into recovery” after brief, high-intensity exercise than after longer, easier workouts, Gibala says. Other researchers have found that similar, intense, brief sessions of exercise improve cardiac health, even among people with heart disease.

There’s a catch, though. Those six minutes, if they’re to be effective, must hurt. “We describe it as an ‘all-out’ effort,” Gibala says. You’ll be straying “well out of your comfort zone.” That level of discomfort makes some activities better-suited to intense training than others. “We haven’t studied runners,” Gibala says. The pounding involved in repeated sprinting could lead to injuries, depending on a runner’s experience and stride mechanics. But cycling and swimming work well. “I’m a terrible swimmer,” Gibala says, “so every session for me is intense, just because my technique is so awful.”
Meanwhile, his lab is studying whether people could telescope their workouts into even less time. Could a single, two- to three-minute bout of intense exercise confer the same endurance and health benefits as those six minutes of multiple intervals? Gibala is hopeful. “I’m 41, with two young children,” he says. “I don’t have time to go out and exercise for hours.” The results should be available this fall.

 

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