Fashionable & Dangerous

Formerly reserved for the beach and locker room, thongs (or jandals as our New Zealand neighbours call them) have been bedazzled and upscaled. They’re sold in some of the most expensive shoe stores, alongside John Fluevog and Manolo Blahnik, making them the summer footwear of choice for trendsetters and followers.

While these lightweight slip-on shoes may be stylish and comfortable, they offer little protection for tender feet. As nothing more than a flat sole holding the foot in position with a y-shaped thong, these g-strings for feet provide no arch support and can cause foot, knee and ankle pain as well as chronic muscle conditions such as plantar fasciitis and tendonitis.

Thongs may alter gait

A 2008 Auburn University (Alabama) study found that with extensive use thongs can change the way we walk. After comparing the gait of students wearing thongs and those wearing athletic shoes, the study concluded that thong wearers took shorter steps.

However, podiatrist Angus Chard, from the University of Sydney’s Footwear Research Department, released his own findings in April this year. They showed that walking in thongs for children is similar to walking barefoot—although he admits that feet may suffer muscle overuse if thongs are worn for too long.

Stride shortens

This is primarily because wearers gripped the front of the shoe with their toes so as to lift the heel, causing the snapping noise as the heel of the foot makes contact with the heel of the shoe. The very design of these shoes prevents wearers from lifting their toes as high during the leg’s swinging phase as other shoes allow, resulting in a shorter stride and an altered walk.

Foot slips and slides

There are dozens of muscles involved in keeping shoes on your feet as you walk, from the foot up into the hips and lower back. Babs Aiyede, certified pedorthist, points to the slippery mechanics of thongs as the root of their deficiency as an everyday shoe.

“One of the main problems with thongs is that they slide around your feet when you walk. Because this type of sandal does not attach securely, its location on the foot varies with each step,” says Aiyede.

What your muscles say to your thongs

It’s this instability that not only puts wearers at increased risk of trips and falls if the foot touches down in an unexpected position, but also forces them to overuse muscles just to keep the shoes on their feet. This can cause muscle strain, which can lead to more serious problems such as tendonitis and plantar fasciitis.

Tendonitis

The posterior tibial tendon helps hold the arch in place, preventing the foot from rolling inward. “Overuse [of] will cause inflammation within the sheath, causing pain,” says podiatrist James Fitzpatrick. Since thongs offer little support, they can cause overuse of the tendon if worn in excess.

Plantar fasciitis

The plantar fascia is a thin band of tissue that stretches from the heel into the toes. When improper foot mechanics stretch the fascia, it can cause tearing at its source, causing severe heel pain. “The more unstable the foot is, the more likely you will develop the condition,” says Fitzpatrick.

At his clinic, Aiyede sees an increase of patients complaining of plantar fasciitis in the summer months. “Every year during the summer sandal season, we see an increase in the number of plantar fasciitis cases in our clinic. In many cases, patients report developing the problem after increased use of thongs,” he says.

“Ideally, in barefoot walking, the first toe extends during the push-off phase of gait—heel lift to toe-off. However, [when] the toes tend to actively flex to grip the thong during this time.

“The change in toe flexor muscle actively creates greater tensile loads on the plantar fascia. Although the body can tolerate this in small doses, prolonged or daily thong wear can cause irritation, inflammation and pain,” says Aiyede.

What to look for when buying summer footwear

Although style icons have transformed footwear from a functional item of clothing into a fashion statement, shopping for your feet should be a careful balancing act between style and practicality.

A running or walking shoe with a thick rubber sole and a firm back area around the heel are always a good option for outdoor activities. But there are safer options for dressing up your feet for the neighbourhood barbecue than fluorescent, jewel-encrusted thongs.

Aiyede recommends finding a provider who understands proper shoe fit and foot function. “A sales clerk that asks your size, hands you a box of shoes, and asks you how they fit is far from ideal,” he says. A professional shoe fitter can determine your individual needs and will take the time to evaluate the fit and function of the shoe as you walk.

If you don’t have the help of a certified pedorthist, there are several details you can look for yourself. Look for sandals that

• securely attach to your feet with a strap
• have ventilation to keep your feet cool and dry
• have appropriate cushioning
• have sufficient arch support, proper toe crest (elevation to support the toes) and heel cupping (contouring around the heels), all of which hold the foot in place

Fitzpatrick recommends holding the shoe in your hand before you buy. Flexible footwear, while comfortable, is not safe for your feet. “If you can easily twist the shoe with your hands, throw them away,” he says.

While fashionable footwear can be enticing, it’s important to also think about the biomechanical function of the feet, avoiding muscle strain and injury. “We tend to sacrifice function for fashion, but there is always a cost for fashion,” says Aiyede.

Thongs if you must

You don’t need to ban thongs from your closet. Thongs are fine to wear to the beach, the pool or around the house, but they are not a stable everyday shoe.

If you do choose to purchase a pair of thongs, look for ones with a footbed. “Thongs are generally flat pieces of foam material with a between-toe strap. As such, there are many areas on the bottom of the foot which do not make contact with this footwear. A thong with a footbed that better represents the contours of the bottom of the foot offers better support,” suggests Aiyede.