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The Federal Trade Commission have announced in a press release that they are taking legal action again the footwear manufacture, Gravity Defyer.
The Gravity Defyer brand was launched in 2008 and their shoes feature a spring under the heel. At that time the Gravity Defyer shoes featured their sperm logo which certainly drew a lot of commentary. More recently they have been making health claims for their shoes that are not supported by the evidence.
These claims include:
“will relieve pain, including knee, back and foot pain;”
“will relieve pain in people suffering from multiple conditions such as plantar fasciitis, arthritis, joint pain, and heel spurs; and”
“is clinically proven to relieve pain, including 85 percent less knee pain, 91 percent less back pain, 92 percent less ankle pain, and 75 percent less foot pain.“
The FTC allege that there is a lack of evidence to support those claims and further allege that the company has failed to uphold previous agreements to not make unsubstantiated claims for their products.
Gravity Defyer have been reported as responding that the suit and its claims violates their First Amendment rights.
This is a product that is getting a lot of traction in Australia where it was developed and where they call this type of footwear, thongs. They are commonly sold in podiatrists offices and are proving quite popular. The amount of arch support built into them is about the same as you could get in a prefabricated or over-the-counter foot support. You can often see comments that anyone who tries them on, buys them as they find them so comfortable.
I had an email question about if any of the toning shoes would be help for a child with Severs disease (calcaneal apophysitis). Firstly the correct name is calcaneal apophysitis and not Severs disease, as its not a disease and it is preferable to no longer name diseases after people. However, Severs is till the most widely used name and is searched more much more often in the search engines.
Secondly, no toning shoes will not help. As the problem with calcaneal apophysitis is with the growth plate at the back of the need bone where the Achilles tendon attaches, toning shoes increase the pull from the Achilles on that growth plate, so are unlikely to be that useful.
If you want a deep dive into Severs disease (Calcaneal apophysitis), then we did this PodChatLive on the condition with a leading expert:
According to Big Class Action, Skechers have proposed to settle the class action for $40 million.
A $40 million settlement has been proposed in a consumer fraud class action lawsuit pending against toning shoe manufacturer Skechers U.S.A.
Entitled Grabowski v. Skechers U.S.A., Inc., No. 3:12-cv-00204 (W.D. Ky.), the lawsuit concerns claims that Skechers violated certain state laws and consumer protection statutes in connection with the marketing and sale of its toning shoes. Skechers denies those allegations.
I have just been looking at Google trends to see what interest there is in toning shoes. There has been a big decline in the number of people searching for ‘toning shoes’ at Google since a peak in December2011:
According to Google Adwords tools, there are 12 000 searches each month for ‘toning shoes’.
This study from researchers at the University of Salzburg in Austria that looked at spinal alignment and muscle activity of selected muscles in the back while standing in typical shoes and MBT shoes.
The main findings were:
Results showed that wearing unstable MBT shoes increased flexion at the mid-thoracic level (0.8°; P = 0.001) and led to greater mean velocities of angular displacement at the thoracolumbar (11.2%; P = 0.003) and at the lumbopelvic (10.8%; P = 0.02) regions, accompanied by more lumbar erector spinae activity (18.2%; P = 0.003).
– this was done during standing and not walking
– it does confirm that there are changes in the low back, spine and muscle activity with the use of unstable or toning shoes
While adding to the body of knowledge on the biomechanical effects of toning shoes, more work is needed to determine the actual ‘clinical’ effects of those changes.
This is certainly a controversial area. Skechers did target an advertising campaign in 2011 aimed at girls which did anger some parent groups and advertising industry groups. The shoes and their promotion were targeted at age 7 and up. The campaign used slim cartoon characters as a girl band and run on the Cartoon Network and Nickelodeon:
There was a change.org petition asking Skechers to stop marketing the shoes:
The commercial in question features a band of thin girls singing about their shoes, and being followed around by surly looking boys dressed like ice cream, burgers, and other “junk” foods. Women have plenty of time to be targeted for their weight throughout their lives. By not only marketing a shoe line to young girls, but also not even having an equivalent for boys Skechers is sending a clear message to girls and women: you’re never too young to start hating your body.
This person’s concerns about Shape-ups for Girls are unfounded and way off base. The whole message behind Shape-ups is to get moving, get exercise, and get fit. This is the same messaging being used by the First Lady’s Let’s Move initiative, which is aimed specifically at children. Please look this site over and ask yourself whether the person who started the petition might voice the exact same concerns about the Let’s Move messaging for children.
Skechers are still producing the shoe.
Putting aside the above concerns about the marketing, what about the use of toning shoes in children?
I think that the predominant consensus among podiatry and health professional groups as well as industry commentators would be that if children wear shoes, then those shoes should not interfere with the normal motion and development of the foot. By that apparent consensus, then a toning shoe would appear to interfere with normal foot function, especially the windlass mechanism of the foot and run the risk of interfering with the normal development of the foot as a consequence. However, given that children do not wear shoes 24/7, it is not clear just how much of a problem that this would be. It is also not clear how much of an interference over what sort of time period is needed to really be a long term problem. There are lots of opinions, rhetoric and propaganda on this with very little science.
Children wearing toning shoes for short periods of time are possibly going to have some benefits in developing improved balance and co-ordination as they do use the muscles differently and the gait is altered. How can that be a problem? It must be helpful. That has to be balanced against the potential of interfering with normal development. It will have to be one of trade-offs.
Will they lead to a weakening of muscles? Unlikely, as most kids do spend a reasonable amount of time running around barefoot. Toning shoes do work some muscles harder, so that is not going to lead to a weakening either.
The alteration in gait that occurs in these shoes may be helpful in some children with some type’s neurological deficits. This is going to have to be a decision made in consultation with the clinician involved in treating the child and if this type of shoe would have a negative or positive effect on the particular gait of the individual.
– Normal development of the foot should not be interfered with by the footwear
– The toning shoes are probably not going to do any harm provided they are used in moderation
– The shoes may even be helpful if worn for short periods
– They may be useful in certain gait patterns in certain neurological problems in children
The windlass mechanism of the foot is an extremely important element in the normal functioning of the foot. It is the foots own natural arch supporting mechanism. The windlass mechanism consists of the plantar aponeurosis or plantar fascia. This powerful ligament attaches to the bottom of the heel bone and to the bases of the toes, so straddles the arch of the foot. During gait, when the heel comes off the ground, the toes flex, pulling on the plantar fascia and winding it around the metatarsal head (the ‘windlass’). This tightens the plantar fascia and supports the arch naturally. There are a number of different dysfunctions of the plantar fascia that can affect the windlass mechanism (see this).
What impact do toning shoes have on this windlass mechanism?
Quite frankly, they actually interfere with it. As most of the toning shoes use designs that incorporate a rocker bottom, the toes do not need to flex during gait, so the windlass mechanism is not ‘tightened’ up and the foot’s natural arch supporting mechanism is not engaged. In a lot of cases, this will not be absolute and there may well be some partial activation of the windlass mechanism. This will depend of the exact toning shoe used and the natural gait of the person using it, so it will be individual.
Is that a problem or not?
It might be or it might not be. It is going to depend on a lot of other factors. It is going to have to be one of trade-offs. For example, what are the benefits of wearing the shoe versus the negative of the windlass mechanism not working. It could well be that part of the ‘toning’ effect for the muscles being made to work harder comes as the muscles need to support the arch more as the windlass mechanism does not support it. There is certainly no research that has looked at the effect of the toning shoes on the windlass mechanism or the consequences of the potential interference with it.
However, those with problems of windlass dysfunction, may need to approach the use of toning shoes with caution as any worsening of their windlass mechanism function could potentially be problematic. More can be found on the problems of the windlass mechanism at Run Research Junkie.
Those with diabetes mellitus have an increased risk for falls. This is mostly due to the development of peripheral neuropathy which reduces the sensory input from the plantar surface of the foot. This neuropathy also puts them at increased risk for complication such a plantar ulcers, often referred to as the diabetic foot. A number of different strategies are often used to reduce the pressures under the ball of the foot to reduce the risk of these complications. One of these methods is a rocker bottom shoe. This has been shown to reduce plantar pressures, but there is a risk it may increase the risk for falls due to the instability the rocker may create.
A study in Gait and Posture from researchers at East Carolina University used 20 healthy controls to investigate what rocker sole shoes did to parameters associated with the center of mass and center of pressure which are measure of postural stability. They concluded:
In young healthy adults, shoes with rocker bottom soles had a destabilizing effect to perturbed stance, thereby increasing the potential for imbalance. These results raise concerns that footwear with rocker bottom sole modifications to accommodate an insensate foot may increase the risk of falls.
– the subjects were healthy adults and not people with diabetic neuropathy.
– its does point to a theoretical increase in instability in those who do have diabetic neuropathy.
– rocker sole shoes probably should be used with caution in those with diabetic foot complications, especially if they have other risk factors present for falls.
According to a press release from Wright & Schulte, LLC, they have filed a suit against Skechers:
alleging that his regular use of Skechers Shape-Ups resulted in five bulging discs in his lower back and his severe back injuries caused him to lose strength in his legs. Filed on December 15, 2012, this case (Case No. 3:12-cv-00838-TBR) names the defendants to be Skechers, U.S.A., Inc., Skechers, U.S.A., Inc., II and Skechers Fitness Group
According to court documents, the plaintiff purchased three pairs of Skechers Shape-Ups in 2009 and 2010 and after regularly wearing these Skechers toning shoes for two years, the plaintiff began experiencing severe lower back pain and decreasing strength in his legs allegedly due to Skechers toning shoes. Upon visiting a physician and undergoing an MRI, the plaintiff was informed that he had five bulging discs in his lower back and that his injuries would require surgery.
Court documents state that the fundamentally precarious rocker-bottom design of Skechers toning shoes caused the plaintiff’s injuries. They also allege that the manufacturers of these shoes did not perform any safety testing even when consumers had suffered from Skechers injuries and that the Skechers corporations never warned the public about the possibility of injuries associated with these toning shoes.
No comment was available from Skechers as they do not comment on litigation.
Does the case have merit? I guess it all depends what risk factors for “bulging disks” were present before they started wearing the Skechers Shape-Ups and how much they contributed to the problem (see the post on achilles tendon ruptures and toning shoes)