Making muscles smarter

2012-12-07T09:00:00Z 2012-12-07T10:41:03Z Making muscles smarterKelsey McQuade and Mitch Smith Medill Reports
December 07, 2012 9:00 am  • 

Donna Meyers' feet are small, so a research assistant at the Rehabilitation Institute of Chicago shoves a sponge in front of each of her size-6 New Balance sneakers.

Then the shoes are latched in place, a safety harness is strung over Meyers’ sweatshirt and she’s ready for her workout. The machine is switched on, and a TV screen just inches in front of her face comes to life with gauges and an array of imagery that track her movement and balance.

At first, Meyers’ legs swing straight forward and straight backward. But as the workout picks up, her feet start rotating a bit, then a bit more, with each step. That rotation is what makes this device unique, researchers say, and what makes it different from the equipment you’ll find at the local Bally Total Fitness — for now at least.

The gauges on the TV swing to the side when sensors show Meyers’ balance becoming uncentered. The more time the needle spends in the middle, the better the workout is going.

This new machine, called the off-axis neuromuscular trainer, is an offshoot of the trusty elliptical trainer that has been a workout favorite for decades.

Northwestern University researchers who developed the new machine hope to see their product — which they say can benefit casual exercisers, dedicated athletes and patients seeking therapy for a menagerie of ailments — to be in athletic clubs by the end of the decade. Their work is part of a broader revolution in exercise equipment, as the neighborhood gym is reconceived as a smart gym, one more effective in treating and preventing injury.

Count Meyers, 74, among the off-axis disciples. The retired architect found that arthroscopic knee surgery and traditional physical therapy offered only temporary relief for her chronic aches.

“At that point,” she said, “I would have done anything because it was really painful.”

She consulted Dr. Joel Press, the medical director of the Spine & Sports Rehabilitation Center at the Rehab Institute. Press suggested the off-axis neuromuscular trainer, which he had developed with colleagues.

After three months of intense training, Meyers was back to bike riding and hiking with her husband. Two years after finishing her regimen, her knees continue to feel strong.

The off-axis trainer is just a part of a workout trend that also includes a NASA-inspired anti-gravity exerciser that allows workouts even during recovery from injuries or surgery.


Go in any gym, and you’ll find much of the same equipment.

Treadmills track the calories you’ve burned, dumbbells line up in 10-pound increments and elliptical trainers work both the lower- and upper-body with minimal resistance.

And while popular exercise machines serve an important purpose, Press said they often have fundamental design limitations.

Take the elliptical trainer, for instance. Someone can spend an hour on the machine, building up a sweat and working off that chocolate muffin they had for breakfast.

But their feet move only straight forward and straight backward on the trainer’s parallel tracks. That arrangement is fine for burning calories and toning a select group of muscles, but it’s at odds with how we experience the world.

The new device more closely mimics the body's natural movement.

“The beauty of this compared to other devices is that others are mostly stepping, while this is side to side,” said Song Joo Lee, a Ph.D. student and a part of the off-axis trainer research team.

Here’s why that’s important: A basketball player spends plenty of time running straight up and down the court. But she also must be able to pivot quickly toward the basket, veer to the right and then dart toward a loose ball on her left.

Even non-athletes have to use muscles that might be neglected at the gym. And because traditional ellipticals target only a limited of number of muscles, Press said training exclusively on those machines can hurt performance and increase the risk of injury.

“Gyms are meant to get lots of people through,” Press said. “It’s not necessarily what’s got the most science beyond it.”

Early research shows that patients are increasing their range of motion by using the off-axis trainer.

In the lab, exercisers see their progress in real-time on a high-definition television screen. The goal is for patients to keep their weight centered even as their feet rotate, a task that sounds easier than it is and can quickly work an out-of-shape journalist into a sweat.

“That’s good for the patient, real-time feedback, so you know what to do,” said Northwestern researcher Li-Qun Zhang.

As the device is commercialized, the giant TV screen could shrink to a smaller touch screen attached to the front of each trainer. The coils of wires sticking out the machine’s rear would also need to streamlined into the machine's body.

There are now six off-axis trainers in use at Northwestern and physical therapy offices. The hope is to start commercial production within five years, though Press and Zhang said a firm date or a future price for the machine hasn’t been set.

Their invention is not the only revamped piece of traditional equipment. The AlterG anti-gravity treadmill, originally designed for astronauts and now used in physical therapy, relies on a pressure-controlled chamber to reduce a patient’s body weight and allow them to build strength even as an injured leg recovers.

“An elderly person who gets a knee replacement for sever arthritis, after the surgery, they have to go through quite a bit of rehabilitation,” said Dr. Dev K. Mishra, AlterG’s chief medical officer.

Before AlterG, such therapies would often be conducted by having a patient walk in water.

While not yet ubiquitous in local gyms, the AlterG is catching on. The Chicago Bulls, Bears and Cubs use the machine, as do private physical therapy offices such as NovaCare in Lincoln Square.

NovaCare physical therapist Ryan Perry said the machine can help obese patients exercise when they are unable to support their full body weight.

“We use it for a lot of different purposes,” Perry said. “One is it helps runners continue running. If they’re training for the marathon and have shins splint, we can dial down the weight so they can continue running during the training program. It’s also nice for obese patients. If you’re 400 pounds and have a lot of stress on your knees, we can dial you down 50 percent to 200 pounds so they can walk comfortably.”

Both AlterG and the off-axis neuromuscular trainer are signs of a shifting dynamic in exercise science, as researchers revisit and redesign long-favored equipment to become more responsive.

“They’re all good for something,” Press said. “If you get a cardiovascular workout, if you get some strengthening, it’s always good. But is it good enough when you’ve had a stroke or arthritis or a bad ankle or all the different things we’re looking for? Just getting stronger is not enough."

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