Shape Ups, Fit Flops and Reebok Easytone: are they worth it?

What they fail to mention, however, is that these studies are not peer-reviewed, and most are of questionable design. For this reason, ACE’s Chief Science Officer Cedric Bryant Ph.D., urges consumers to beware of studies sponsored by manufacturers. “Depending on how they conduct the study, they can prove anything they want to prove.”

The Study

To test the effectiveness of the shoes and evaluate their claims, a team led by Porcari, John Greany, Ph.D., Stephanie Tepper, M.S., Brian Edmonson, B.S., and Carl Foster, Ph.D., designed a pair of studies, one evaluating exercise responses to walking in traditional athletic shoes (a New Balance running shoe) versus the popular toning shoes. The second study evaluated muscle activation when walking in regular athletic shoes compared to toning shoes.

For the exercise response study, researchers recruited 12 physically active female volunteers, ages 19 to 24 years. All study subjects completed a dozen five-minute exercise trials in which they walked on a treadmill for five minutes wearing each type of shoe. The shoe order was randomized as the subjects were asked to walk at 3.0 mph with a 0% grade hill; 3.5 mph/0% grade; and at 3.5 mph/5.0% grade. Meanwhile researchers monitored each subject’s oxygen consumption, heart rate, ratings of perceived exertion (RPE) and caloric expenditure.

To measure muscle activation, researchers recruited a second group of 12 physically active female volunteers, ages 21 to 27 years, who performed a similar battery of five-minute treadmill trials (as explained above) rotating shoes at random. Researchers used electromyography (a.k.a. EMG) to record muscle activity in six muscle areas: gastrocnemius (calf), rectus femoris (quads), biceps femoris (hamstrings), gluteus maximus (buttocks), erector spinae (back), and rectus abdominis (abs), as subjects walked in each of the four pairs of shoes. As a baseline for EMG analysis, maximum voluntary isometric contractions (MVIC) on all muscles were also performed using manual muscle techniques prior to testing.

The Results

Across the board, none of the toning shoes showed statistically significant increases in either exercise response or muscle activation during any of the treadmill trials. There is simply no evidence to support the claims that these shoes will help wearers exercise more intensely, burn more calories or improve muscle strength and tone (Table 1).

“We tested RPE, which is basically how hard one is working, and oxygen consumption, how much oxygen you take in versus being at rest, and caloric expenditure and we found no significant difference between any of the shoes,” says researcher Stephanie Tepper, M.S. “So the toning shoes definitely don’t do more than the regular running shoe.”

As for the muscle-activity testing, the results were strikingly similar. There was no significant difference in EMG levels in any of the muscles tested between the four types of shoes (Figures 1–6).

“Looking at the EMG data, we saw nothing there as well,” says Porcari. “There were some subtle differences—sometimes they favored the regular running shoe and other times they favored the toning shoes—but it was nothing statistically significant.”

The Bottom Line

“Don’t buy these shoes because of the claims that you’re going to tone your butt more or burn more calories. That’s absolutely wrong,” says Porcari.

Then how do researchers account for the anecdotal evidence (found on blogs, etc.) from those who wear the shoes and claim their muscles get sore, which must mean the shoes are working?

“Do you feel different when you’re wearing these shoes? Of course you do because you’re walking on probably an inch worth of cushioning,” explains Porcari. “They feel different, and that’s why when people first wear them they’re probably going to be sore because you’re using different muscles. But if you wear any sort of abnormal shoes that you’re not used to wearing, your muscles are going to get sore. Is that going to translate into toning your butt, hamstrings and calves? Nope. Your body is just going to get used to it.”

Bryant isn’t surprised by the findings: “When you think about it, it’s kind of the same old song and dance,” he says. “People will still fall prey in their search for the quick-and-easy fitness solution. These shoes are just another attempt to find that magic bullet.”

Bryant says he’s also concerned that extended wear of these toning shoes may alter the walking gait mechanics of wearers and, in some cases, potentially cause problems for those who may already be at risk for lower-extremity issues. But to evaluate that will require another longer-term study. And although the toning shoes don’t deliver on their advertised claims, Porcari mentions there may be potential that these shoes could improve wearer’s balance over time, but that too will require a long-term training study.

In the meantime, Bryant is reaching for the silver lining.

“These shoes may be encouraging a fair number of people who probably wouldn’t put on a normal pair of walking shoes and go out and walk, to do so because they think they’re getting some super toning effect,” says Bryant. “So if you want to look at a positive, it’s probably serving as a bit of a motivator to get a group of inactive individuals to at least get up and get moving.”

And, no matter how you spin it, that’s a good thing.

This study was funded solely by the American Council on Exercise (ACE). Visit the ACE Get Fit^TM website for additional  ACE-sponsored research studies and to read the full findings of the toning shoes study.

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Mark Anders is an award-winning journalist who has covered a wide range of topics from rock star profiles to surfing river waves in Africa. His work has been published in more than 20 different magazines and books.