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Prescription for strength: Researcher seeks 'optimal dose' for seniors' weightlifting

thumbnail Study in strength—Researcher Dr. Marcas Bamman (right), with VA and the University of Alabama at Birmingham, talks with study participant Barbara Wiggins and exercise physiologist Craig Tuggle. (Photo by Joe De Sciose)

Marcas Bamman, PhD, was a competitive soccer and basketball player in his younger days. Running up and down a field or court demanded lots of stamina, and skillful handling of the ball required endless hours of practice. But it was another aspect of sports that caught his scientific curiosity: What exactly makes muscles bigger and stronger? And what is it that causes them to lose their mass and strength?

Today, Bamman is exploring these questions as a research scientist with VA and the University of Alabama at Birmingham. His work focuses on older adults.

The answers Bamman is seeking are more complex than a matter of simply using or not using muscles. That's only the beginning. His research goes deeper:

  • What is the ideal strength-training regimen for older people?
  • What biological factors lead a person to respond better to one form of exercise over another?
  • What molecular mechanisms can be targeted to turn atrophying muscle cells into growing ones? And can the work lead to new treatments for diseases that involve muscle atrophy or wasting?

Regarding the first question, Bamman, who directs mobility research for the Geriatric Research, Education and Clinical Center at the Birmingham VA, recalls the specific episode that sparked his interest.

He and other researchers with VA and UAB conducted a clinical trial from 2001 to 2006 comparing exercise outcomes in young versus older volunteers. They used the standard strength-training regimen recommended by most professional societies: three times per week, high-intensity.

"What we found was that the older folks adapted, but not nearly as well as the young," recounts Bamman. "You might say sure, young people are always going to adapt and perform better than older people, younger muscles are going to adapt more favorably than older ones. But we didn't want to accept that as the end of the story. Maybe we don't have the optimal dose for the old. Maybe we're not giving them a fighting chance."

Pet peeves of an exercise physiologist

Marcas Bamman, PhD, an exercise physiologist and researcher specializing in strength training, describes the most common mistake he sees in the weight room, among people of all ages:

"I see a lot of people who don't perform a full range of motion because they're trying to lift too much. With a squat or leg press, for example, people won't go deep into hip or knee flexion (bending) because the load they have is way too heavy for them. When you get into that joint position where you're at a mechanical disadvantage, you need to lighten up on the load if you're going to get the full benefit of the motion."

On a more fundamental note, he laments that many lay people don't understand that there are two main types of exercise, both of which are vital.

"People who are not versed in this field often don't differentiate between strength training and fitness training," he says. "Pedaling a stationary bike is certainly going to improve cardiopulmonary fitness, and improve fatigability in your leg muscles, but it's never going to build any muscle." The same would go for an elliptical trainer, rowing machine, or Nordic Track.

"People might say, I do a Nordic Track, so I've got upper and lower body muscles working. I'll tell them, the Nordic is contraction intensity low enough so you can continually perform that movement for 30 or 40 minutes. Strength training is at intensity high enough that you can't perform the movement for more than about 30 seconds. What's happening in your muscles is different in each situation."

Bamman adds: "I'm certainly an advocate of both, in some combination, but our main research interest, especially with the older population, is getting the dosing as optimal as we can for the resistance [strength] training. I think that's where the real knowledge gap is."

Experimenting with different regimens

Bamman and his colleagues have now been working to discover the right training recipe, one that might give seniors a better "fighting chance." For the past five years or so, study volunteers aged 60 to 75 have been working out in a gym on the UAB campus under the watchful eyes of researchers and trainers with the VA and the university. A last wave of volunteers is expected to complete the study within a couple of months. The project is funded by the National Institute on Aging.

The volunteers, about 70 men and women, go through four weeks of pre-training and then 30 weeks of sweat- and grunt-inducing workouts. But the training is harder for some than others.

That's because the workouts vary, depending on which of four groups the volunteer is in. One group does a high-intensity workout three times per week. Another does high intensity two days per week. A third does high intensity on Monday and low intensity on Friday. The fourth does high, low, high on Monday, Wednesday, and Friday, respectively.

High intensity means more weight is lifted; low intensity means less weight. The low-intensity regimen in this case involves lifting a load that's only 40 percent of the person's maximum, for only one set of 12 repetitions.

"We have them stop, even though they probably could go on and do 25 to 30 reps," notes Bamman.

What's more, his team, with the help of a machine shop, has fitted standard weight machines with hydraulic cylinders to support the weight stack on its way down. This setup is used for the light-intensity workouts. Bamman explains what this means for participants' muscles:

"When you do weight training, typically you push or pull a weight and then you lower it back down. We took out all that lowering work, which is known as eccentric contraction, or eccentric loading. That's when the muscles are lengthening, and that's where you get all your soreness. When you lift a weight, that's called concentric. That's when muscles are shortening. If all you do is concentric work, you really don't get much delayed-onset soreness or inflammation. Some of that delayed soreness and inflammation is good, but too much is bad."

Using the lighter loads and only muscle-shortening movements, the researchers also wanted to "develop as much explosive muscle power as we could" in the participants. "We have them move the load very fast," says Bamman.

Finding the 'optimal dose'

By tracking how older people respond to different versions of strength training, Bamman hopes to identify an "optimal dose"—at least for the majority of exercisers. This means getting to the desired body composition—namely, stronger and larger muscles—with the least effort.

"Frankly, not every older adult should be prescribed the exact same program," acknowledges Bamman. "But in the end, when we complete this project, we will have enough data to identify responders and non-responders in each of the four prescriptions. While it's true that no one size fits all, because of genetic predispositions and all the other factors that play into it, at least we can come away from the study and say with prescription A, only 65 percent respond well, whereas on prescription C, 85 percent respond well. We'll be able to say for most people, such-and-such prescription is optimal. I do think one program will rise to the top for most people."

Bamman expects the findings will yield insights to help not only the older population at large, but also those coping with chronic diseases.

"This dosing idea is something we want to carry into multiple diseases, not just aging," says Bamman. "As a consequence of living many years with congestive heart failure, or chronic kidney disease, or osteoarthritis, or COPD, one of the side effects that often goes ignored is muscle atrophy. People will have a physical and functional decline due to the loss of muscle tissue. That's on top of the normal aging atrophy."

Bamman's pursuit—learning how to get the most bang for the buck out of weightlifting—may yield important knowledge to help Veterans and others in failing health.

Adjunct approach for chronic disease

One study now under way by the VA-UAB group is enrolling people with Parkinson's disease. "We think we can impact their symptoms, their quality of life," says Bamman. "One of their primary complaints is fatigability, and we think we can have a big impact on that through strength training."

In the optimal-prescription study, in addition to tracking participants' outcomes, the researchers are analyzing tissue samples in the lab. So far, they've seen that the genetic expression profile seen in muscle tissue affects how people respond to training, although the study isn't large enough to pinpoint the role of specific genes.

Another key factor, says Bamman, may be the amount of muscle stem cells in muscle tissue. These cells mature into new muscle cells to replace old or damaged ones.

Bamman hopes his group's findings and insights—from the gym and the lab—will eventually impact how trainers, physiologists, and physical therapists work with older people.

Biological and physiological nuances aside, motivation remains a key obstacle to getting people to exercise, whether it's lifting weights or anything else. Bamman believes programs such as VA's MOVE! Program—geared to overweight Veterans—are a good start, but more is needed. "I'd like to see more emphasis on exercise in general and strength training in particular. I hope it becomes an integral part of every patient interaction in VA—the idea that exercise is medicine. We need to say to a patient, here's a prescription—here's something you need to do along with taking your medications. I hope we get to that point."

For now, he's got lots of good feedback from study participants who have discovered—many for the first time in their six or seven decades—the benefits of strength training.

"I think it's been eye-opening and confidence-building for most of our volunteers," shares Bamman. "We get emails or phone calls from folks who go on to do things they say they'd never have dreamed of doing before they were in the study. We had one woman who was a retired nurse, and when she finished the study she maintained her strength training but also got back on a bicycle and got real interested in endurance cycling. She was about 68 or 69 at the time, and she rode her bike across the state of Georgia, with a group. She wrote me a nice letter."

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