The Running Shoe: Excellent Science or Excellent Marketing?

The shoe industry has evolved most rapidly over the previous decade and will continue to evolve as new technologies and markets are formed. We are in an era where athletes are training in barefoot running shoes and it’s not uncommon for a shoe to carry a microprocessor to play music and/or retain information for further gait evaluation post training. This article aims to unravel the hype and assist coaches on advising the most appropriate footwear for their athletes.

Why Do We Wear Running Shoes?

The primary purpose of a shoe is to protect the foot; a shoe however also has the potential to change lower limb/foot function .Due to the relationship between footwear and pathology, health professionals have a responsibility to consider footwear characteristics in the etiology and treatment of various patient presentations. A correctly prescribed shoe can assist with healing rates, improve mobility and reduce injury risk of the lower limb. In the United Kingdom foot and ankle problems account for approximately 8% of musculoskeletal consultations in primary care. Whilst further investigations are often required for foot and ankle pathology the correct shoe is an easily accessible intervention for early management of symptoms.

What Are The Key Features Of A Shoe?

A shoe can have the greatest biomechanical effect on the rearfoot- ankle and subtalar joints, midfoot – midtarsal joints and the metatarsals at the forefoot . The key features of a shoe include the heel counter, density and placement of foams on the medial sole, shoelace system and forefoot rocker angle. These shoe prescription variables have the greatest potential to influence gait and are taken into consideration when choosing a shoe for particular foot posture and foot/ankle pathology.

Summer footwear, which includes the use of ‘open back’ slip-on footwear, increases the incidence of achilles and calf muscle pathology. Early intervention strategies such as changing attitudes to appropriate footwear can help reduce the risk of this common injury and commence early treatment for pathological patients. The sandal with adjustable rearfoot, midfoot and forefoot straps is advisable for patients wanting to wear a summer shoe. This will ensure the main anatomical foot structures are in a position of optimal functional efficiency.

Footwear Prescription: What Is The Gold Standard?

The gold standard of footwear prescription is the running shoe. The spectrum of functional components does not present in any other shoe category. Whether the foot requires pronatory control, pressure reduction or improved sagittal plane motion there is a running shoe on the market that can cater for this. It has been generally accepted throughout the allied health and retail communities that footwear prescription comes in 3 categories; motion control, stability and neutral. However recent research has challenged this prescription process.  In my opinion, running shoes should be prescribed based on the persons functional foot posture and injury history.

If a patient does not run on a regular basis, running shoes can still be prescribed for the pathological foot. When foot pathology presents to general practice an appropriate running shoe can be recommended for use as a first line treatment. Advice may be for the patient to wear their appropriate running shoes for the majority of weight-bearing time till further investigations, diagnosis or referrals have been implemented.

The Role of Cushioning

During running the body experiences an initial peak force of between two and three times the person’s body weight. During the 1980s running shoes were marketed with suggestions that the primary goal was to reduce initial peak force. Research over a decade later revealed that shoes to not reduce the initial peak force!

Cushioning materials are marketed very heavily in today’s running shoes. Whilst we cannot affect the initial peak force with cushioning material alone we can however slow down the rate at which force is applied to the body and reduce pressure on the sole of the foot by 17-33% - important variables to consider when prescribing shoes for our patients.

When Should You Replace Footwear? 

Generally, a running shoe will last between 800-1200km. For the regular walker and runner this equates to approximately  9-18 months.  The materials in running shoes are not overly durable. After running just 500km foot pressure can increase by as much as 100%.  The foams used in footwear manufacture are closed cell, once ruptured can never return to original form. These ruptured compression lines are visible, it is recommended to update the shoe once these lines are first noticed.

Signs of a worn out shoe include firmness under foot, reduced cushioning, significant wear on the upper and/or wear through the outsole. Some runners find it useful to alternate a second pair of running shoes – which will help improve the durability.

Barefoot Running Shoes – The Bare Essentials

Since the release of the Nike Free shoe in 2006 the barefoot running shoe market has been growing.  A barefoot running shoe can be prescribed for the athlete wanting to improve intrinsic foot muscular strength or as an aid to assist running efficiency. Care has to be taken when recommending these shoes to pathological general populations.

The risks associated with the use of barefoot running shoes include overuse musculoskeletal conditions of the foot and ankle specifically tendonitis and tendinopathies of the achilles and tibialis posterior tendons. The forefoot is also susceptible to pressure type pathologies such as capsulitis, bursitis and metatarsalgic symptoms. An increase in forefoot load may also lead to early degenerative arthritis particularly of the 1st metatarsal head. It is a matter of weighing up how susceptible your patient is to these types of injuries and working together whilst maintaining open communication to achieve the desired outcome.

There have been suggestions that barefoot running shoes contribute to a higher incidence of midfoot ground contact during gait; midfoot ground contact (as opposed to initial heel contact or forefoot contact) has been shown to be the most efficient strike pattern whilst running.  Barefoot running shoes can assist, however are not necessary to achieve this.

A barefoot running shoe should be prescribed for the elite running athlete with sound medical history looking to modify gait patterns to achieve a desired outcome. Barefoot running shoes should only be worn for a minority (10-15%) of training and monitored closely by their coach.

Conclusion

The running shoe will certainly continue to evolve. We have a responsibility as health professionals to keep up with the new technology in order to achieve the most desirable outcomes for our patients. However we also have a responsibility not to lose our perception in the hype and marketing surrounding running shoes.