Anti-gravity Treadmills Help after Injury

If you read running magazines you might have seen stories or advertisements for "anti-gravity treadmills". Runners shared their experiences with this machine in a recent Washington Post article:

I had been reading about “anti-gravity treadmills” in running magazines for a couple of years, wondering occasionally how such a thing could work, when I received an offer from Gainesville chiropractor Kevin Maggs to try one.

At his office, Maggs helped me slip on a specially designed pair of shorts before I stepped onto the treadmill he bought a few weeks ago from the AlterG company of Fremont, Calif. He raised a plastic bubble that enclosed the device up to my waist, and I zipped the shorts to it, creating an airtight seal.

Like any other treadmill, this one had speed and incline controls, and I started walking, just as I have during countless other warm-ups. But then I began to take weight off my feet in 1 percentage-point increments by pumping air into the clear bubble. Slowly the air pressure began to support me.

At 80 percent of my body weight, I felt as if I could fly. I told Maggs to go home; I’d be here running all day. At 20 percent of my body weight, the least the machine allows, my toes were barely touching the treadmill.

Medical benefits

“You feel invincible,” said Lachlan Leach, who was walking slowly on the treadmill when I arrived, the first steps of her rehabilitation for a stress fracture in her foot. “You feel like you can just take off running.”

She can't; that wouldn’t be good therapy. But placing a small load on the stress fracture while it heals, and staying in shape rather than eliminating all cardiovascular activity, will speed her recovery, Maggs said. Some health insurance may cover the therapy, he said.

“It’s very hard to tell a runner not to run,” said Maggs, who estimates that about 80 percent of his patients are runners and triathletes. We are an obsessive lot, prone to persisting through injuries no matter how much long-term damage we’re doing.

Joe Kehoe swears the treadmill saved his half-marathon in March. The 35-year-old Haymarket resident had been training diligently for the race when he strained a calf muscle trying to alter his gait.

“I would have had to completely stop running,” Kehoe told me. Instead, Maggs treated him, then put him on the device at a slower speed than normal and at about 60 percent of his body weight. As his injury healed, Kehoe gradually increased both. He said he ran a personal best in the 13.1-mile race.

And at Walter Reed Army Medical Center, wounded veterans, most of whom suffered limb damage from roadside bombs, are using the treadmill.

“It lets them run with confidence,” said physical therapist Bo Bergeron. “They’re not going to fall. And if they stumble, they’re not going to hit the treadmill.”

The treadmill isn’t perfect. The model for athletes sells for $75,000; the one designed for medical use costs $30,000. Therapists can’t get at a patient’s legs to help while he’s walking. It gets really warm in that bubble, the shorts and air pressure are somewhat uncomfortable and when you remove the air you feel the toll in your quads. So far, there are only a handful in this area, according to the company’s Web site.

Invention and success

The idea of supported running is nothing new. Rehab facilities feature treadmills with harnesses that hold up patients as they recover from leg injuries and strokes. Coaches and physicians have been sending injured athletes to work out in the pool for years. These are much cheaper and, in most cases, more accessible alternatives. But they also are much less precise, and water will not support as much weight.

The treadmill’s purpose isn’t only therapeutic. Athletes, especially elite runners, have figured out that they can train at faster paces while saving wear on their legs. There’s even a formula, worked out by the company: For every 10 percent decrease in body weight on the treadmill, cardiovascular fitness can be maintained by increasing speed 0.6 miles per hour.

The development of the anti-gravity treadmill is a story in itself. NASA scientist Robert Whelan spent years working on technology that would help keep weightless astronauts in space on their treadmills. For a graduate school engineering project, his son, Sean, decided to reverse the concept and build a treadmill that takes weight off runners’ legs.

He later formed a company and in 2006 demonstrated the first one for Alberto Salazar, the legendary former marathoner who coaches elite U.S. distance runners at the Nike Oregon Project, according to Kate Yanov, director of marketing for AlterG. Salazar bought five, she said.

From there, the treadmill spread to more than 80 professional and collegiate football, basketball and soccer teams, including the Washington Redskins, the New York Knicks and AC Milan, according to the company’s Web site. The U.S. military has bought them to help rehabilitate troops with leg wounds and traumatic brain injuries, Yanov said. Top women marathoners have trained on them during their pregnancies.

The company has sold more than 400 to date, Yanov said, about 65 percent to medical facilities and the rest to athletic teams or sports facilities.

Source: Washington Post, Lenny Bernstein 4/19/11

High-intensity vs. endurance workout--which is the victor?

Endurance training and high-intensity workouts--do both offer cardiovascular benefits? A study finds that each form of exercise has health benefits, with intense workouts perhaps edging out the competition.

The study focused on a group of 47 adolescents (average age about 16) who were assigned to a moderate exercise group, a high-intensity exercise group or a control group for seven weeks. The moderate exercise group did 20 minutes of steady running three times a week, while the high-intensity group did four to six repeats of an all-out sprint with brief recovery periods three times a week.

Both groups showed evidence of cardiovascular benefits at the end of the study. The high-intensity group had substantial improvements in systolic blood pressure, aerobic fitness and body mass index. Among the moderate-intensity group's improvements were aerobic fitness, body fat percentage, body mass index and insulin concentrations. No injuries were reported.

The moderate-intensity group burned more calories than the high-intensity group: 4,410 versus 907 on average. But the study authors noted that the high-intensity group exercised for a total of only 63 minutes, 15% of the 420 minutes spent by the moderate-intensity group.

Most exercise experts recommend that workouts include both endurance and interval training, which can be done outside or in a gym.

Although this was a small study, lead author Duncan Buchan of the University of the West of Scotland was optimistic about the implications of the results: "This is the first study to demonstrate the effects of a novel interval training program on both traditional and novel (cardiovascular disease) risk factors in adolescents," he said in a news release. "Larger scale and extended interventions must be undertaken so that the long term impact and effects of intermittent training programs on unfavorable metabolic profiles may be investigated further."

The study was released Wednesday in the American Journal of Human Biology.
Source: Jeannine Stein, Los Angeles Times; 4/6/11

Weight Training

Resistance exercise such as weight training affects blood vessels differently than aerobic exercise and offers other cardiovascular benefits, finds a new study.

Researchers at the Appalachian State University in Boone, N.C., compared blood vessel (vascular) responses to two types of moderate-intensity workouts: three sets of 10 repetitions of eight resistance exercises and 30 minutes of aerobic cycling.

There were significant differences in the vascular responses to the two types of exercises. Resistance exercise produced greater increases in blood flow to the limbs, while aerobic exercise reduced arterial stiffness, but without an increase in blood flow.

"Resistance exercise may offer greater benefits from the increases in blood flow to active muscles and could be implemented as a companion to an aerobic training program," wrote study leader Scott R. Collier, of Appalachian State University, and colleagues in a press release.

"The present study indicates that an acute bout of resistance exercise shows many favorable cardiovascular benefits and should therefore be considered as part of a daily exercise training program," the researchers concluded.

Source: November issue of Journal of Strength and Conditioning Research.

Some Adults Unable to Benefit from Work-Outs

Recently, researchers in Finland made the discovery that there are those who just do not become fitter or stronger, no matter what exercise they undertake. To reach this conclusion, the researchers enrolled 175 sedentary adults in a 21-week exercise program. Some lifted weights twice a week. Others jogged or walked. Some did both. Before and after the program, the volunteers’ fitness and muscular strength were assessed.

At the end of the 21 weeks,some improved their strength enormously, some not at all. Others became aerobically fitter but not stronger, while still others showed no improvements in either area. Only a fortunate few became both fitter and more buff. As the researchers from the University of Jyvaskyla wrote with some understatement, “large individual differences” exist “in the responses to both endurance and strength training.”

Hidden away in the results of almost any study of exercise programs is the fact that some people do not respond at all, while others respond at an unusually high rate. Averaged, the results may suggest that a certain exercise program reliably will produce certain results — that jogging, say, three times a week for a month will improve VO2max (maximal oxygen capacity) or reduce blood pressure; and for almost any given group of exercisers, those results are likely to hold true. But for outliers, the impacts can be quite different. Their VO2max won’t budge, or it will fall, or it will soar.

The implications of such wide variety in response are huge. In looking at the population as a whole, writes Dr. Jamie Timmons, Ph.D., a professor of systems biology at the Royal Veterinary College in London, in a review article published last month in The Journal of Applied Physiology, the findings suggest that “there will be millions of humans that cannot improve their aerobic capacity or their insulin sensitivity, nor reduce their blood pressure” through standard exercise.


But what is it about one person’s body that allows it to react so vigorously to exercise, while for others the reaction is puny at best? One answer, to no one’s surprise, would seem to be genetics.

In other words, this issue is as intricate as the body itself. There is a collection of compelling data that indicate that about half of our aerobic capacity “is genetic,” Dr. Timmons wrote in an e-mail. “The rest may be diet,” or it could be a result of epigenetics, a complicated process in which the environment (including where you live and what you eat) affects how and when genes are activated. “Or it could be other factors,” he said. Although fewer studies have examined why people respond so variously to strength training, “we have no reason to doubt,” he said, that genetics play a similar role.

But none of this means that if you once took up jogging or weight lifting and didn’t respond, you should take to the couch. It may be that a different exercise regimen would prompt beneficial reactions from your particular genome and physiology, Dr. Timmons said. (Although scientists still have a long way to go before they can say, definitively, who needs what exercise, based on genetic and other differences.) In the meantime, Dr. Timmons stressed, even low responders should continue to sweat. Just as scientists don’t yet understand the complicated underpinnings of the body’s response to exercise, they also don’t necessarily understand the full range of exercise’s impacts. Even if you do not increase your VO2max, Dr. Timmons said, you are likely to be deriving other benefits, both big and small, from working out. Exercise does still remain, “on average,” he said, “one of the best ‘health’ treatments we have.”

Source: NY Times, 11/17/2010