Insoles Reduce Impact for Runners

MADISON – For many, running isn’t merely a sport or hobby. For the avid, running is an intricate system of punishments and rewards. And the rewards – health, fitness and the physical and psychological satisfaction of pursuing a challenging goal – are made more difficult because of a common punishment – injury.

Stress fractures, shin splints, plantar fasciitis – runners go to great lengths to avoid these obstacles that prevent them from pounding out their weekly miles. They search for the right shoe, the right stride and the right training routine.

In a study recently published in the Journal of the American Podiatric Medical Association, two UW Health researchers examined an affordable and easy method that may reduce impact force injuries common to distance running.

Katy O’Leary, a physical therapist at the UW Health Rehabilitation and Athletic Performance Clinic who specializes in athletic injuries, joined Bryan Heiderscheit, PhD, an associate professor in the University of Wisconsin School of Medicine and Public Health and director of UW Health Sports Medicine’s Runners Clinic, to examine the beneficial aspects of shock-absorbing insoles placed in running shoes.

While the results of the study stop short of guaranteeing a reduction in injury for runners, O’Leary and Heiderscheit did find that insoles significantly reduce impact forces associated with running.

The Study

Podiatrychannel.com, a health information Web site maintained by board-certified podiatry physicians, lauds running as great exercise but cautions about the toll it takes on the body.

Jogging, the Web site states, "generates forces equivalent to at least three times the body’s weight (with each step). It is important to do everything possible to protect the feet, ankles, knees, hips and lower back vertebrae."

To find if cushioned insoles provide such protection, O’Leary and Heiderscheit recruited 16 recreational runners from the Madison area. All were between 20 and 36 years old and screened to eliminate anyone with a recent history of lower-extremity injury.

"They had to run an average of 20 miles per week and couldn’t have any neurological or musculoskeletal impairments that wouldn’t allow them to run comfortably," O’Leary says about the selection process.

The subjects were given identical shoes and asked to perform 10 15-meter trials during which they ran at their own pace across a force plate, which measures a runner’s ground reaction force (the force projected back up through the body while running). To ensure the runners used their normal stride, they were not told to hit the force plate with their right foot, the foot from which O’Leary and Heiderscheit derived the data.

Accelerometers were attached to the subjects’ ankles to measure the amount of tibial acceleration that occurred while they ran. O’Leary and Heiderscheit were also careful to monitor the consistency of the subjects’ knee angles when their feet hit the force plate, because widely varying angles could have skewed the results.

Five of the trials were conducted with only shoes. For the remaining five, subjects used insoles, manufactured by the Ohio-based company Sorbothane. O’Leary and Heiderscheit both stressed that Sorbothane was not involved in any phase of the study, other than the insole donation.

"They were blind to everything until we sent them the final results paper," Heiderscheit said.

The Results

"We found a couple of good things," O’Leary says. "When the runners had the insoles in, there was a significant reduction in the ground reaction force at the initial contact point."

On average, the ground reaction force was nearly 7 percent less with the insoles. It may seem like a paltry number, but remember that’s 7 percent less force per step.

"When you think of a 7 percent reduction for, say, a 10-mile run, that’s a lot," Heiderscheit says.

Tibial acceleration also decreased, by 15.8 percent. Both factors are considered potential culprits for impact force injuries.

Ramifications

O’Leary and Heiderscheit emphasize the study results do not definitively prove that cushioned insoles reduce running injuries. That’s a much larger task and would require a more elaborate setup.

"We couldn’t come out and say it’s going to reduce injuries but it certainly has the potential to," Heiderscheit says. "The piece we’re missing is following these people over time. We’d have to account for their training differences."

Still, both are encouraged sufficiently to broach the subject with their patients.

"In my practice I’m willing to say, ‘Try it out,’ " O’Leary says. "If it’s uncomfortable, you’re probably not going to run normally. But if you have a pair of insoles that you’re comfortable with and you feel good about it, there’s a chance it might help reduce your risk. It’s something I’m willing to put out there."
And Heiderscheit believes the benefit of insoles is more likely to be reaped by casual runners rather than hard-core trainers who have their sights set on future marathons or Ironman competitions.

"If you’re putting in 10 to 12 miles per week, your body’s adaptation to those types of impacts will be much slower and you won’t have the same level of tissue strength as somebody who’s putting in 50 miles per week," he says.

Plus, the insoles could save money, because they protect not only the runner from impact force but insulate shoes from trauma, as well. With insoles at about $15 to $20 per pair, they’re a relative bargain compared with shoes that often cost $100 or more.

"Shoes are expensive but insoles are cheap," Heiderscheit says. "They can get you maybe an extra 200 miles out of your shoe."

 

Train your brain: Can jogging make you smarter?

Physical activity boosts the flow of blood to the part of the brain that is responsible for memory and learning, promoting the production of new brain cells

Exercise won't just get you fit – it can also make you more intelligent. Simon Usborne discovers how to shape up your mind

We don't need to be told that exercise is good for us. We know that it combats cholesterol, we know boosts our hearts and we know it stops the pounds from piling on. But, beyond the obvious physical benefits of a good cycle, run or swim, a growing body of evidence suggests that getting breathless can also build the brain.

Spark: The Revolutionary New Science of Exercise and the Brain, which is published later this year, shows how even regular brisk walks can boost memory, alleviate stress, enhance intelligence and allay aggression. John Ratey, an associate professor of psychiatry at Harvard Medical School in Boston and the book's author, says that exercise stimulates our grey matter to produce what he calls "Miracle-Gro" for the brain. "I can't understate how important regular exercise is in improving the function and performance of the brain," he says. "It's such a wonderful medicine."

 

Happiness

If the mere thought of trudging round ice-bound playing fields at school was enough to bring you out in a cold sweat, the idea that exercise makes us happy might sound perverse. But, beyond the (potential) mood-lifting effects of fresh air and scenery, evidence suggests that pounding the pavement can also change the way our brains work to make us happier, or even stave off depression. "Exercise is as good as any anti-depressant I know," Ratey claims.

Last December, scientists from Yale University wrote in the journal Nature Medicine that regular exertion affects the hippocampus, the area of the brain responsible for mood. Tests on mice showed that exercise activated a gene there called VGF, which is linked to a "growth factor" chemical involved in the development of new nerve cells. Tests show that this brain activation lifts a person's mood. Participants in one recent German survey were asked to walk quickly on a treadmill for 30 minutes a day over a 10-day period. At the end of the experiment, researchers recorded a significant drop in depression scores. Scientists are now working on a drug that mimics the effects of the VGF gene to market it as an alternative to conventional antidepressants.

 

Stress

If, by around 4pm, it feels as if a stressful day at work has turned your brain to blancmange, it might not only be down to overwork or a shortage of double espressos. We respond to stress in the same way our ancestors did – by adopting a "fight or flight" response. Adrenalin and other hormones are released into our bloodstreams and our muscles are primed for response. The problem is that, these days, stress is more likely to be brought on by a tricky PowerPoint presentation or a job interview than an attack by marauding lions, so the toxins that build up for a physical response have no outlet. The results can be good; the cardiovascular system is accelerated and we can work harder (for a while, at least), but others are not so good; stress slows down the gastrointestinal system and reduces appetite, and can overexcite the brain, fuzzing our thought. By responding to or anticipating stress with fight (kickboxing or judo, say) or flight (30 minutes on the treadmill, say, or 50 lengths of the pool), blood flow to the brain is increased, allowing the body to purge the potentially toxic by-products of stress. According to Ratey, exercise also helps in the long term. "It builds up armies of antioxidants such as Vitamins E and C," he says. "These help brain cells protect us from future stress."

 

Intelligence

Observers of the game of football might refute the claim that exercise leads to greater intelligence – and they would be partly right, says Ratey. "Exercise doesn't make you smarter, but what it does do is optimise the brain for learning."

Physical activity boosts the flow of blood to the part of the brain that is responsible for memory and learning, promoting the production of new brain cells. Several schools in the US and the Netherlands have taken note. Pupils at Naperville Central High School near Chicago, for example, start the day with a fitness class they call "Zero Hour PE". Equipped with heart monitors, they run laps of the playground, and teachers say exam results have soared since the keep-fit initiative kicked off.

Meanwhile, in Amsterdam, a test involving 241 people, aged 15-71, compared physical activity with the results of cognitive tasks. The researchers documented improved results among people who were more active, especially those in younger age groups.

Yet more research suggests that exercise boosts intelligence in the very, very young. Experiments on rats at the Delbrück Centre for Molecular Medicine in Berlin showed that baby rats born to mothers who were more active during pregnancy had 40 per cent more cells in the hippocampus, the area of the brain responsible for intelligence. If the same is true in humans, we can expect Paula Radcliffe's baby, Isla, to be a genius; Radcliffe was training for the New York marathon until the day before she went in to hospital to be induced – and won the race just nine months after giving birth.

Aggression

A few rounds with a punch bag or a game of squash are great ways to release pent-up aggression, but exercise does more than "get it out your system", says John Ratey. "People assume exercise reduces aggression by burning energy. In fact, exercise changes your brain so you don't feel aggressive in the first place."

The frontal cortex is the part of the brain that decides whether you throw a punch or take something on the chin. Reduced activity in the region, a trauma or abnormal development can result in an inability to control violent urges. "This area makes us evaluate the consequences of our actions," Ratey says. "It's the part of the brain that puts the brakes on when the ref makes a terrible decision and you want to beat him up." Exercise increases activity in that area, boosting rational thought, which makesus less likely to lash out.

 

Memory

Most of the competitors at the annual World Memory Championships could hardly be described as the epitome of physical fitness but, according to Ratey and other scientists in the field, a good workout does much to boost recall, especially as we clock up the years.

"When we're exercising, we're using nerve cells in the brain which help build up what I call brain fertiliser," he says. Ratey is talking about new research that suggests exercise increases blood flow to the part of the brain responsible for memory, and improves its function. In MRI scans on mice, conducted last year by neurologists at Columbia University Medical Centre in New York, the animals were shown to grow new brain cells in the dentate gyrus, which is affected in age-related memory decline.

Research on humans is ongoing but Ratey is convinced that physical activity has a similar effect. He says: "Exercise does more than anything we know of to boost memory."

 

Addiction

Smokers keen to quit cigarettes probably won't celebrate the news that exercise could be the key to a fag-free life. But research by British scientists suggests that as little as five minutes of brisk walking can reduce the intensity of nicotine withdrawal symptoms. In the tests, researchers asked participants to rate their need for a cigarette after various types of physical exertion. Those who had exercised reported a reduced desire to smoke. "If we found the same effects in a drug, it would immediately be sold as an aid to help people quit smoking," Adrian Taylor, the study's lead author at the University of Exeter, said last year.

The principle is that exercise can stimulate production of the mood-enhancing hormone dopamine, which can, in turn, reduce smokers' dependence on nicotine. "Dopamine works by replacing or satisfying the need for nicotine," Ratey explains.

Whether the findings will lead office-based smokers to dash out for a jog remains to be seen. After all, you wouldn't want to get addicted to exercise.

How much do you need?

You don't have to become a marathon runner to benefit your brain. The mainstay of exercise is simple, brisk walking, Professor Ratey says.

You'll feel the benefit even from a 30-minute walk. "That's what people need to be doing as a minimum, ideally four or five times a week. If you want to do more, then great."

Professor Ratey also recommends interval training – really pushing yourself hard for between 20 and 30 seconds while running, cycling or swimming, so that you are momentarily exhausted.

Do, say, two minutes of walking, 30 seconds' sprinting, then two minutes of walking again. It doesn't have to be a lot for a long time, but you will really notice the difference. "The side effects on the body aren't bad either – I lost 10 pounds in no time," Professor Ratey says.

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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