Wearing unsupportive shoes puts you at risk of injury, says Dr Tamsin Lewis – even when you’re not training or racing

Can flip-flops cause injuries? Photo by M.Markus (Flickr.com)

Photo by M.Markus (Flickr.com)

I cringe when I see triathletes walking about in flip-flops, ballet pumps or Ugg boots. As trendy and cool as you may think they may look, I don’t think they’re worth the risk.

We’ve systemically de-conditioned our feet by years of walking around in thick-soled trainers and shoes with anti-pronation arch support. This means that our choice of footwear is important, and unsupportive shoes keep physios in business but the athlete out of pocket.

Nicole Oh, the head physio at Pearson Physio in south-west London, says she often sees athletes who’ve suffered injuries after wearing flip-flops. “The main problem with flip-flops is their complete lack of arch support,” she explains.

“A weak and unconditioned foot – which the majority of us have, since we cradle our feet in supportive shoes for most of the year – may not be able to cope with a sudden change in footwear when the sun comes out. This increased demand and overloading of the ankle stabilising muscles (the tibialis posterior on the inside and/or peroneals on the outside) can cause overuse injuries in their tendons, resulting in pain, swelling and weakness.”

Wearing flip-flops may not directly result in running injuries, though if you try running in them you’ve got a fair chance of doing some damage. But even worn for walking, they can contribute to injury development solely on the principle of overload.


Potential injuries

  • Posterior tibial tendon dysfunction – inflammation or tearing of the tendon that attaches the calf muscle to the arch of the foot, caused by lack of control of pronation (the foot collapsing inwards)
  • Peroneal tendon injuries – the peroneal muscle in the lower leg can become chronically tight to stop the foot collapsing inwards (pronation) and then be subject to excess strain when it has to control inward movement of the ankle
  • Plantar fasciitis – inflammation of the band of tissue that runs along the sole of the foot, caused by clawing of the toes to stabilise the foot


  • Reduce the load on the irritated muscle/tendon via taping and supportive footwear
  • When injury has healed, strengthen the ankle and foot


  • Walk around barefoot at home year-round to help strengthen your feet and improve proprioception (awareness of the position and movement of your body parts)
  • Work on foot and ankle strength
  • Instead of flip-flops, try Birkenstock-style sandals, which are more supportive and don’t encourage toe-clawing
  • Try shoes from Vivo Barefoot or Vibram that are designed to improve foot strength. Remember to only walk in them for a short period of time initially, and build up your time in them gradually