I used to be a big fan of slip-on shoes, wearing them on holiday, to pop in and out of the house. I even got some particularly pretty ones to wear at my nephew's wedding! That was before I became aware of what this type of shoe was doing to my body! I can think of five good reasons why I will never go back to wearing them!
Read on and make your own mind up! I'm hoping this article will encourage you to observe what is happening with your body when wearing any slip-on shoes. Body awareness is key.
1) Flip flops don't hold on to the foot so toes have to grip to prevent them from slipping off at some point in gait, usually when the foot is behind you (and/or the big toe and second toe will squeeze together to keep the shoe on), but also in the front foot. This introduces unnecessary tension in the toes, front of ankle and shin, leading to chronic stiffness over time in your feet, ankles, knees, hips and spine. Toes have the ability to clench and prevent you from taking a tumble, acting as an emergency stop but not as part of a natural, relaxed gait pattern.
2) Flip flops and other slip-on shoes interfere with a natural gait. Toes need to extend at the metatarsophalangeal joint (rather than flex at the phalanges) on the back leg, to allow a posterior push-off, involving calves, glutes and hamstrings.
Toes also extend on the front leg before landing, whether in walking or in running. They spread slightly as well. If wearing flip flops, this natural, relaxed motion (toe abduction and extension) is replaced by the opposite motion (toe adduction and flexion) in order to keep the flip-flop from slipping off.
3) Flip flops are most commonly associated with slips, trips and falls, especially when the ground is wet (the foot slides and may go over the front of the flip flop, which may fold underneath, or the strap may come undone altogether! These shoes are not made to last! Also, they don't allow you to move quickly if the situation requires it. If you do, then the risk of mishap increases.
4) Slip-on shoes encourage laziness as no effort is required to put them on or take them off. This convenience is what makes them so popular! You just slip them on or off, no movement of the hip involved! When a part of the body is not used, it weakens and atrophies.
5) Finally, they often have a thick, stiff sole, restricting movement of all the soft tissue that reside at the bottom of the foot, and are rarely wide enough to give room to all of the toes. The little top may overlap or curl in or the big toe may overlap and move inward, affecting your stability. They also tend to have a cushioned sole, interfering with sensory feedback from the ground.
Do this quick test:
Stand on one leg for 30 seconds to a minute, with both legs straight. Notice what your toes are doing. If they tend to grip, I recommend you ditch the slip-ons for minimalist sandals (photos below right), which feature a strap round the back, a thinner sole giving you more sensory feedback (not as much as being barefoot, obviously) and will allow a smooth transfer of your weight from the heel to the ball of the foot, with nothing flapping about underneath! Do make sure the straps are fitting snugly and make them a little tighter in wet weather and a little looser in hot weather. I would also spend more time barefoot and practise the micromovement demonstrated below (top of the foot stretch) to loosen up your toe gripping muscles!
For more micromovements designed to unstiffen your feet and the rest of you, you are more than welcome to subscribe to the Virtual Treatment Room.
Photo credits: click on each photo for external link.
Photos without a link are my own.
Minimalist footwear: Earthrunners. Xero Shoes offer a good alternative. (I have no deal with either company!).
Further reading: Does flip-flop style footwear modify ankle biomechanics and foot loading patterns?