Can a pair of shoes help you burn more calories, tone your butt, banish cottage cheese thighs, and curb joint pain?
The answer depends largely on who you ask.
Rocker sole shoes started as more of a specialty shoe for people with diabetes or ankle problems, but they are increasingly marketed as toning shoes, and many shoe companies are now in on the game. There are some technical and design differences between shoe brands, but the basic principles remain the same.
These shoes have an unstable, strongly curved sole. Walking in them is akin to exercising on a balance or wobble board in the gym or barefoot along a sandy beach. Advocates say that this instability forces you to use muscles that you otherwise would not -- namely those in your feet, legs, butt, and abs -- which could lead to weight loss. The shoes can also change your posture and gait and take pressure off of achy, overused joints.
But don't stop paying your gym dues just yet.
A new study, released by the American Council on Exercise (ACE), shows that toning shoes including Skechers Shape-Ups, MBT (Masai Barefoot Technology), and Reebok EasyTone don't help you exercise more intensely, burn more calories, or improve your muscle strength and tone.
"Toning shoes appear to promise a quick-and-easy fitness solution, which we realize people are always looking for," ACE chief science officer Cedric X. Bryant, PhD, says in a written release. "Unfortunately, these shoes do not deliver the fitness or muscle-toning benefits they claim."
In the new study performed by researchers at the University of Wisconsin-La Crosse, 12 active women aged 19-24 completed a dozen five-minute intervals on a treadmill while wearing Skechers Shape-Ups, MBT, Reebok's EasyTone Reeinspire shoes, or traditional New Balance running shoes as researchers monitored how hard they worked -- technically called exercise response. A second group of 12 women aged 21-27 performed a similar battery of five-minute treadmill tests in the various shoes while researchers measured muscle usage in their calves, quads, hamstrings, buttocks, back, and abs.
The results? There was no significant difference in calories burned or muscle usage between the four types of shoes, the researchers reported.
Many people do feel that these shoes work because of soreness in different muscles. Don't be fooled, Bryant says. The shoe's unstable sole design does cause wearers to use slightly different muscles to maintain balance, resulting in temporary soreness that will subside as the body adjusts to the shoe, he says.
That said, "If these shoes are serving as a motivator for individuals to walk or get moving more often, that is a good thing, even if they don't produce the dramatic toning and calorie-burning results people think they are getting," Bryant says.
Additional studies looking at how toning shoes affect balance over time are under way, he says.
Shoe Companies React
Shoe makers are unshaken by the ACE study on toning shoes. Leonard Armato, president of Skechers' fitness group, in Manhattan Beach, Calif, stands behind his product 100%. "I have not a doubt that the Shape-Up technology requires you to make a little more effort with each step, burn more calories, and activate more muscles," he says.
Armato does, however, have some doubts about the new study results. "This study is not published in a peer-reviewed journal, and only involved 12 young, fit women who walked for five minutes on a treadmill," he tells WebMD. "ACE represents fitness trainers who are at odds with the toning industry, and don't want toning to take root."
It's a turf war, he says. "They have the most to lose if people start walking around in these shoes as opposed to going to a gym and hiring a personal trainer."
Bill McInnis, the head of advanced innovation for Reebok, based in Canton, Mass., created the technology used in Reebok's EasyTone line. "We looked at stability balls from the gym and incorporated that same thinking into a shoe," he says. "The idea was that introducing soft, micro-instability in the shoe would cause you to have to rebalance a bit with every single step and cause your muscles to work a little harder all day long," he says.
"The new study makes bold statements without the data to back it up," he tells WebMD.
"When you walk on a soft sandy beach, you will work harder so when you build a shoe that is softer when you land on it, you get the same effect and are working the muscles harder," he says.
Reebok's EasyTone shoes "increase muscle activation, but we don't make claims about burning calories or weight loss."
MBT issued this statement to WebMD: "Independent research and published studies have shown the benefits of MBT footwear. Studies have been conducted by researchers at a number of educational and research institutions. We stand by the conclusions of that research and those studies."
The Podiatrist's View of Toning Shoes
Cary M. Golub, DPM, a podiatrist in Long Beach, N.Y, says toning or rocker-bottom shoes have a place in certain people's shoe collection.
For starters, these shoes may help relieve pain among people with heel pain, he says. "They take the pressure off of the heel and give more support to the ankle," he says.
"These shoes put the strain on your hamstrings and glutes, so if you are not athletic or a seasoned walker, they may hurt the muscles that they are supposed to help," Golub says. "If you are not used to firing these muscles, the shoes may hurt."
Golub's advice: "Break them in slowly for an hour or so. Don't start walking 2 or 3 miles in them."
A Doctor's View of Toning Shoes
Najia Shakoor, MD, an associate professor of internal medicine at Rush Medical College and an attending physician at Rush University Medical Center in Chicago, spends a lot of time in her lab studying shoes and determining which types are best for people with arthritis.
Her verdict on toning shoes for people with arthritis: Thumbs down.
"I don't think there is any evidence to suggest that they do anything beneficial for arthritis," Shakoor says. Her research shows that flat, flexible shoes are more joint-friendly. "This is the complete opposite of the rocker bottom," she says.
Shakoor is not sold on the role that these shows play in improving fitness levels of people without arthritis, either.
Yes, "your posture improves because you are wearing an unstable shoe, so you have to balance yourself by standing up straight," Shakoor says. But "more research is needed to see who they are appropriate for."