Busting myths about running shoes

Jean-François Esculier, one of the world leaders in new trends in the prevention of running injuries recently presented some of the latest research regarding footwear. This has completely changed the way we think about and prescribe footwear.

What we have been told about footwear (from shoe companies):

• Several features of shoes can affect foot function, and therefore prevent injury. The optimum shoe is one that matches your specific biomechanical weakness, and running style.
• The heel counter, at the upper rear part of the shoe, should be made of rigid firm material to aid in stabilising the ankle.
• The midsole of the shoe absorbs shock and offers support for neutral, pronating and over-pronating runners. 
• Most running injuries are caused by external factors (shoes, running surfaces, etc.) or intrinsic factors (lack of flexibility, muscle weakness, abnormal biomechanics…).
• Heel to toe drop (pitch) is often taken as the best descriptor of "minimalism shoes".
• If we "run heavy" or are overweight we need a cushioned shoe to help absorb the shock and pressure.

What the latest research tells us about footwear:

• Pronation control technologies are ineffective.  Absorption technologies in shoes do not reduce the stress on the body, in fact they increase load on certain joints.
• Research does not support the prevention of injuries due to technology promoted by shoe companies.  
• Recommending running shoes on the basis of foot type (flat, high or universal) constitutes an unjustified practice. In addition, the efficiency of pronation control systems in governing the movements of the feet and legs has been challenged.
• 80% of injuries are caused by mechanical overload from a change of habit. The best way to prevent injuries is the quantification of mechanical stress. Footwear and biomechanics are only a small part of the puzzle.
• The isolated effect of heel to toe drop (pitch) on running kinematics is not that convincing.
• There is no scientific basis for justifying that relatively heavy people, or those that "run heavy" should wear thicker, more cushioned and more rigid shoes.  In fact, it’s quite the opposite.  A more “maximalist” shoe will encourage a greater foot strike and increased loading leading to greater forces through the body. 
• There are multiple factors to consider when describing "minimalism shoes".

So what now?

We recommend running in minimalist shoes (in other words, simple, low shoes that allow better contact with the ground), for several reasons:

• There is no proof that modern shoes with their technologies of motion control, stability, and cushioning actually prevent injury.
• Modern shoes change running biomechanics by increasing heel strike and decreasing the body’s protective intrinsic impact-moderating behaviour.
• Modern shoes significantly decrease stride pace.
• Modern shoes alter the ‘natural’ sequence of muscle contractions in the legs and back.
• Modern shoes and their cushioning do not reduce stress on the bones and may even increase it.

As part of a study led by researchers from Laval University, 42 experts from 11 countries defined minimalist shoes and built the Minimalist Index (MI). Minimalist shoes are footwear providing minimal interference with the natural movement of the foot.   For example, some Vibram Five-Finger models show MI scores close to 100%. In contrast, ultra-maximalist shoes, such as some Hoka models, have an MI closer to 0%.

The level of minimalism of running shoes can be rated with a scale that considers five characteristics:

• Drop
  • The difference between shoe thickness under the heel and where your toes start. The closer to 0, the higher the rating on the Minimalist Index.
  • Most people stop here when thinking of "minimal shoes".
• Heel height
  • The thinner the shoe, the higher the score on the stack height subscale.
• Flexibility (longitudinal and torsional)
  • The more flexibility, the higher the score on this subscale.
• Weight
  • The lighter the shoe, the higher the rating on this subscale of the Minimalist Index.
• Stability technologies
  • The least amount of technologies in your shoe means that the Minimalist Index will be higher.
     

Should I and how do I switch to different shoes?

Consider the Minimalist Index to plan your transition.  Switching from one model to another may lead to injury when done too quickly.

Runners should aim for 1 month of transition time for every 10% change in the Minimalist Index score. For example, you should plan a two-month transition period when switching from shoes rated 50% to others rated 70%.  

Depending on your habits and your tolerance to change, you may require more time or even less time to transition. Too quick of a transition towards a more minimalist shoe (higher score on the MI) will typically result in symptoms to your foot, Achilles tendon or calf muscle.  Equally, too quick of a transition towards a more maximalist shoe (lower score on the MI) will typically cause symptoms to your knee, hip or lower back, simply because different shoes load different tissues of your body differently.  

In the end, everything is a matter of adaptation! Listen to your body!

What about footwear for children?

The elements that are essential in selecting a pair of shoes for children are relatively straightforward and widely accepted by all experts in this field.

• The main role of shoes is to protect the foot from injuries and infection.
• The selection of a pair of shoes for children should be based on the “barefoot” model so that the foot develops in an optimal way. Stiff and tight shoes are not recommended.
• The more often children are barefoot, the better.

Furthermore, there is no age when the child/teenager should start wearing maximalist running shoes (cushioned, elevated heel, relatively rigid). However, if a teenager has already grown accustomed to maximalist running shoes, there should be a progressive transition to minimalist shoes spread over a few weeks in order to allow the foot to adapt

New to Running? Returning to running after a long break (greater than 12 months)?

Beginners with no running experience (or have not run for more than 12months) are “virgins” in terms of their own biomechanical learning curve.  It is therefore important to integrate as early as possible shoes that interfere as little as possible with natural biomechanics as well as with the development of the feet.

Minimalist running shoes will help runners develop more efficient impact-moderating behaviours. In other words, they will learn to run light.

Conclusion

80% of injuries are caused by mechanical overload from a change of habit. The best way to prevent injuries is the quantification of mechanical stress. Footwear and biomechanics are only a small part of the puzzle.

We are in a society driven by marketing and non-clinical logical or scientific research. The research and development departments of the companies only offer the glitz. Most importantly, no clinical studies justify the use of these technologies. 

It is important to understand that some new technologies proposed every year by companies may have no scientific basis and are designed for a simple objective, that is, to sell specific products.

In the absence of scientific proof of the protective aspect of modern shoes and in light of the indirect evidence of their probable detrimental effect, consider entrusting your body to what nature intended and run barefoot. If weather, running surfaces, or the social environment prevents you from doing so, opt for the minimalist approach.

Remember:

Any change in your training program, if too significant, entails the risk of overloading tissues and therefore causing injury. A change in shoe must be done as gradually as a change in volume of training and will affect everyone in different ways. To ensure this progression and for personalised tips, give the team here a shout. and always remember to listen to your body first!