Shoes with 'toe spring' may increase risk of injury, study finds
They may feel comfy, but wearing shoes that curve upwards at the front may be weakening your foot muscles and increasing your risk of injury.
This curvature, known as a “toe spring”, is a common feature of many shoes, especially trainers. It helps the front part of the foot to roll forwards when walking or running, enhancing the comfort of thick and cushioned soles. But despite their ubiquity, the effect of toe springs on our foot muscles had not been well studied, until now. Freddy Sichting at Chemnitz
University of Technology in Germany and his colleagues used cameras and sensors to measure forces on the feet of 13 volunteers as they walked barefoot on a treadmill, and while wearing sandals with varying degrees of toe spring.
They found that the greater the upwards curvature, the less work the foot muscles had to perform. “We think this is why shoes with toe springs are so comfortable,” says Sichting, whose research was published in the journal Scientific Reports. “The foot muscles have to do less work to stabilise the toe joint when you lift up your heel and push forwards.”
Yet this comfort may come at a cost: although the study did not measure the long-term impact of toe springs, Sichting suspects that, over time, the muscles may weaken to the point where other structures in the foot, such as ligaments, take over. This may increase susceptibility to conditions such as plantar fasciitis, where the band of tissue that supports the arch of the foot becomes inflamed, resulting in intense heel and arch pain.
Trevor Prior, a consultant podiatric surgeon, senior clinical lecturer at Queen Mary University of London and spokesman for the College of Podiatry, said: “It is clear that this type of shoe does alter function and preserve energy, hence the benefit seen with running shoes designed in this manner.”
However, he stressed that the potential reduction in muscle strength and risk of injury remained theoretical. Even so, Prior advised wearing a range of footwear to minimise the negative effect that any specific shoe design might have over time.
This is also Sichting’s approach: “I use all kinds of shoes, but also barefoot shoes. Our feet evolved to walk barefoot over millions of years, and modern shoes with toe springs, cushioning, and arch support are a very recent phenomenon. They give comfort, but I’m also aware of the downsides, so I try to train my foot muscles regularly.”