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)
A study published in Clinical Biomechanics (online Sept 2012) looked at pain levels in people aged 40-65 with plantar fasciitis. Using a visual analogue pain scale, they compared the use of foot orthotics to toning shoes to foot orthotics and toning shoes.
The pain scores on the VAS for the 3 conditions were:
Rocker shoes and foot orthotics: 9.7mm
Rocker shoes: 30.9
Foot Orthoses 29.5
So the rockers shoes combined with foot orthoses produced the best results and the authors concluded:
The findings indicate that a combined prescription of rocker sole shoes and custom-made foot orthoses had greater immediate therapeutic effects compared to when each treatment had been individually prescribed.
– this is not a very commonly used intervention for treating plantar fasciitis
– this was an acute intervention and the participants were not followed over time
– the VAS is not the most validated measure for pain levels in plantar fascitis
For more on plantar fasciitis, see this post.and this essay. Run Junkie has one of the sensible approaches to it.
A recent news report talks about litigation against Skechers from a male who claims that his Achilles tendon was ruptured from the use of their Shape Up toning shoes. The case has not been heard yet and there is no statement from Skechers.
Is the claim valid?
Toning shoes do alter the way you walk. They do alter the loads on different tissues, and yes they do make the calf muscles work harder, so they do place a greater load on the Achilles tendon. Much more is needed to rupture it though (more on Achilles ruptures), so to claim it is the cause is, in my opinion, a bit of a stretch. There must be a number of other risk factors present first and an Achilles tendon rupture is usually accompanied with simultaneous ankle dorsiflexion and knee extension. That will possibly be increased somewhat in toning shoes that have a rocker bottom. Generally a number of risk factors need to be in place for the rupture to happen, so the toning shoes can only be one of them.
As by way of analogy, there was the controversy when the Cox-2 inhibitor, Vioxx which was used as an anti-inflammatory agent was withdrawn from the market due to the increased risk for cardiovascular events. A number of people who had heart attacks or strokes while on this drug sued. Most of the cases failed, as they already had the risk factors for the heart attack or stroke (see this Wikipedia discussion) and Vioxx was not found to be the causative factor.
It will be interesting to see which way this Skechers case goes, or if it is just settled (which would be shame, as I would like to know which way the courts would rule!). Would they rule in favor of the litigant that the shoes caused the Achilles rupture or will they rule like in the Vioxx cases that other risk factors were already present?
Ever since MBT started the footwear category for the toning shoes, they have been plagued with the illegal reproduction of their shoes. Like any company they are constantly having to fight this on many fronts. One of these fronts is to try and get the websites that sell the illegal copies removed from the search engines. In order to maintain transparency, Google reports the number and some information on the copyright removal request that it gets and actions. Here is the details on the requests received from Masai Marketing and Trading AG for the MBT shoes. This give an indication of the extent of the problem.