WELCOME TO THE Canadian Federation of Podiatric Medicine - @CFPM01 #CFPM2018

WELCOME TO THE
                Canadian Federation of Podiatric Medicine
               2018 CONFERENCE

www.podiatryinfocanada.ca                 @CFPM01 #CFPM2018

Running Shoes?
- enhance performance?

- prevent injury         Craig Payne

Running Shoes
• Do they prevent injury?
• Do they enhance performance?

Paradigm

•   Motion Control
•   Stability
•   Cushioning       Does getting it right
•   Minimalist        mean less injury?

“Overpronation”

“The truth about …”

Rationale

• “overpronation”  bad 
  “control” it with design
  features in running shoes
• Part of the ‘pronation
  paradigm’ for prescribing
  running shoes

History
• Grew out of running boom in late 70’s
• As a category it has declined in share
  – Minimalist trend
     • Feel
        – Ride
     • Responsiveness
  – Research
     • Laboratory
     • Outcome
• Category “name”  ? Bad name
  –  use ‘design features’

Lots of “throw away” lines …
• “BBS”
• “They don’t control motion”
  – “You can’t control motion”
• “They are dead”

Design Features

• Not one design feature
• Many different design features
• Different shoes in this category
  have different features

Minimalist Index

Multi-Density Midsole

Thermoplastic Medial Post

Rigid Heel Counter

Elevated Medial Insole

Supportive Tensioned Upper

Medial Heel Flare

Others
• Medial wedging
• Midsole geometries
  and torsional links
• Windlass enhancing
• Proprietary features
  – Eg Asics Space
    Trusstic
  – Eg Hoka J-Frame

Do they work at controlling motion?
• The research:
  – Shoe vs foot movement
  – Skin vs bone movement
  – Lump all the design features into one
    category
  – What measure?
    • Calcaneal eversion
    • Tibial rotation
  – What was actually causing the
    “overpronation”?
    • Never taken into account

Research

• Mixed
  – They do control motion
  – They do not control motion
• Can cherry pick evidence to support your argument
• Mean vs subject specific responses

Do shoes control motion?
• 2011
• All three interventions were effective in
  reducing calcaneal eversion (p

• Depends on cause:
  – Tight calf muscles
  – Forefoot varus
  – Weak gluteal muscle

                Never taken into
                 account in the
                   research

Outcome Studies

• Do they make a difference in the “field”

“This study is unable to provide support for
the convention that highly pronated runners
should wear motion control shoes. Current
conventions for assigning stability categories
for women's running shoes do not appear
appropriate based on the risk of experiencing
pain when training for a half marathon.”

• Knapps
• Mallisoux

- meta-analysis of 3 studies
- Military population
- Allegations from a participant

• “The overall injury risk was lower in participants who
  had received motion control shoes. Based on
  secondary analysis, those with pronated feet may
  benefit most from this shoe type.”

Aside: Funding source

Conclusion for outcomes…
• Depends on how much weight you want to
  give to each study and preconceived biases:

• Ryan et al
   – Fragility analysis might show weak
   – Funded by Nike
• Knapik et al
   – Soldiers – allegedly did not wear much
• Malisoux et al
   – Funded by Decathlon

What next
• Did not account for the cause of “overpronation”
• Analogous with ‘dose-response’ in drug trials

• “Tuning” running shoes
• Vibration dampening

Enhance Performance

• Is it legal?

International Amateur Athletic Association (IAAF) Rules

(Old) Rule 143.2:
Athletes may compete barefoot or with footwear on one or
both feet. The purpose of shoes for competition is to give
protection and stability to the feet and a firm grip on the
ground. Such shoes, however, must not be constructed so
as to give an athlete any unfair additional assistance,
including by the incorporation of any technology which will
give the wearer any unfair advantage. A shoe strap over the
instep is permitted. All types of competition shoes must be
approved by IAAF.

New rule 143.2:                  (1 Nov 2017)

• Athletes may compete barefoot or with footwear on one or both feet. The
  purpose of shoes for competition is to give protection and stability to the feet
  and a firm grip on the ground. Such shoes, however, must not be
  constructed so as to give athletes any unfair assistance. Any type of shoe
  used must be reasonably available to all in the spirit of the universality of
  athletics.
• Note (i): Adaption of a shoe to suit the characteristic of a particular athlete’s
  foot is permitted if made in accordance with the general principles of these
  Rules.
• Note (ii): Where evidence is provided to the IAAF that a type of shoe being
  used in competition does not comply with the Rules or the spirit of them, it
  may refer the shoe for study and if there is non-compliance may prohibit such
  shoes from being used in competition.

Study

• “A spokesman for Nike has told the Guardian the shoe,
  which the company believes makes runners 4% more
  efficient compared to its previous fastest marathon trainer,
  adheres to the specifications of the International
  Association of Athletics Federations. When the Guardian
  contacted the IAAF to ask whether Nike’s carbon fibre
  plate was legal, a spokesman said it was interested in its
  technical advances but wanted to make sure they – and
  shoes from other manufacturers – conformed to its rules.”

• “We are aware of the speculation around the shoe and have
  received inquiries about new designs of shoes currently being
  worn by elite athletes,” said a spokesman. “However, this is not
  linked to just one manufacturer. There is development in shoe
  tech across the board.
• “Because of this speculation and the increased interest in the
  development in this area the IAAF is going to discuss shoe
  approval processes as defined by the competition rules as part of
  the agenda at the IAAF Technical Committee in two weeks’ time in
  Zaragoza, Spain, to see if we need to change or review
  approvals.”

Is the VaporFly 4% compliant with 143.2?
• Evidence is they help
• Words used in Nike’s patent
  – "In conventional footwear, little or none of this mechanical
    energy is recovered to contribute back to ongoing movement.
    Reducing this energy expenditure and/or improving the energy
    recovery can potentially improve locomotion efficiency”
• Ross Tucker:
  – “To sum my position up, I think the addition of any device that
    purports to act as a spring (and the Vaporfly Elite clearly has
    this) should be banned for the credibility of performances both
    now and into the future.”

Old 143.2
• Such shoes, however, must not be constructed so as to
  give an athlete any unfair additional assistance, including
  by the incorporation of any technology which will give the
  wearer any unfair advantage.
New 143.2
• Such shoes, however, must not be constructed so as to
  give athletes any unfair assistance

Timelines
• Nike Patent published (Oct 2016)
• Nike press release re Breaking2 (Dec 2016)
    – Working on a shoe
• IAAF Technical Committee meets (late March 2017)
    – Amends rules
    – Appears to have taken no action
•   Nike announce the Nike VaporFly 4% (May 3 2017)
•   Breaking2 (May 6, 2017)
•   Nike VaporFly 4% comes to market (August 2017)
•   New IAAF rules come into effect (1 Nov 2017)
                      Nothing
                    happened yet

Line in the sand

• Yes, the VaporFly does return
  energy
• So does the Adidas Boost, Brooks
  Levitate, etc
• But VaporFly (carbon plate) and
  Spira (springs) have ‘inserts’ in
  addition to the energy return from
  the foam midsole.

Spira (~2007-2008)
• Wanted to be banned USATF  PR blitz
• Offered big money to anyone to wear and win
• Spira had filed suit against USATF and IAAF alleging the
  two groups had violated the Sherman Anti-Trust Act and
  restricted trade by banning Spira's shoes.
• USATF: "confirming that USATF has not examined or
  'banned' the shoe, as we have publicly stated multiple
  times over the last year-plus.“
• Spira believed they banned as they broke rule 143.2

What will happen?
• Need a ruling by the IAAF
  and not by armchair
  lawyers

Conclusion

• Injury prevention?
• Enhance performance?
  – legalities