Wearing shoes that elevate the foot at the heel (yes, even the trainers in the picture and so called “flats” with the tiniest of heel!) also affects the position of your pelvis and leads to compensatory mechanisms, in order to maintain balance, eventually leading to discomfort and pain in the lower back. Wearings heels leads in effect to a tucking of the pelvis, cancelling out the recruitment of hamstrings and glutes.
Each step you take in your positive heel shoes requires flexion at the hip and allows no extension as there cannot be a pushing-off action. Also, the weight of your body is not spread evenly between front and back, creating an excessive load on your toes and ankles.
Minimal shoes have a wide toebox, allowing your toes to spread and participate in your every move, keeping your toe muscles active and strong. This, in turn, helps improve stability in joints such as hips, knees and ankles, reducing the risks of injury later on. And of course, the more muscles are recruited, the more oxygenated blood gets pumped round your body, easing the load on the heart.
Wearing no or minimal shoes allows you to push off with the back leg, recruiting hamstrings and glutes, keeping them healthy and strong. No need to do hundreds of squats for a toned backside. Just wear minimal shoes and learn how to walk efficiently.
Now for a word of warning: going from wearing traditional shoes to minimal shoes MUST happen gradually, reducing the heel bit by bit or going barefoot for a short time at first, then longer and longer so the transition is comfortable. Tissues need time to adjust. Your achilles tendon will also be happier with a gradual approach.
Wearing no or minimal shoes takes you back to the freedom you enjoyed in your childhood. As a child, I was so much happier barefoot, to the annoyance of my parents who told me again and again to wear my shoes outside and my slippers inside! It just goes to show that sometimes, the child does know best!
PS: If you do decide to go barefoot, I would recommend you first read Whole Body Barefoot - Transitioning Well to Minimal Footwear, by Katy Bowman.