Protective Equipment

• Factors important to prevention of athletic injuries:

  • design (prevent and protect)
  • proper fit
  • proper selection
• Protective equipment should:

  • be simple to fit and maintain
  • be durable and reliable
  • be inexpensive
  • have minimal functional interference
• 4 protective principles:

  • deflection
  • dissipation
  • deformation
  • absorption
• Deflection:

  Important properties:

  • roundness
  • smoothness
  • ridges
  • hardness
• Dissipation:

  Qualities:

  • disperse force over larger surface area
  • layers/padding
  • many materials
• Deformation:

  Change in shape or structure:

  • cantilever pads

  Blows apart at high force:

  • bike helmet
• Absorption:

  Materials:

  • felt
  • foam (open and closed cell)
  • air
  • fluid
• Different Densities:

  • increased density = greater resistance at high force
  • decreased density = more absorption at low force
• Open cell foam:

  • sponge
  • low resilience (no bounce-back)
  • pads bony prominences
  • protects skin from protective equipment
  • decreased density = more absorption at lower force
• Closed cell foam:

  • mainly for protection
  • high resilience (rebounds)
  • less cushioning at high impacts
  • increased density = greater resistance at high force
• Fitting equipment:

  • mold to body
  • allow function
  • allow for quick removal in emergencies
• Important to fit helmets to:

  • prevent injuries
  • maintain vision
  • ensure you can play
• Fit of helmet changes due to:

  • temperature
  • hair length
  • deterioration of internal padding
  • loss of air
• Purpose of shoulder pads:

  • covers shoulder and cups deltoid
  • keep neck unrestrictive
  • snug lacing
• Modifying equipment:

  • modifications done via manufacturer’s specifications
  • modifications should not alter fit of original equipment
  • modifications should not increase stress or damage to original material
• What to think about when considering sport equipment:

  • biomechanics of body
  • individual activity level
  • protection/performance demands (what are you trying to protect against?)
• Analysis of equipment; look at:

  • fit
  • ventilation
  • temperature
  • wear recertification
  • quality/certification
  • outer surface/shell
  • inner surface/liner
  • method of attachment
  • design
• Lasts:

  • external last = shape (of shoe)
  • straight = stability -> motion control; increased base of support; for mobile/flat foot
  • curved = neutral -> stability; medial deviation of foot
• Lasts:

  • internal last = construction (area between foot and midsole)
  • board last = increased torsional resistance to pronation
  • slip last = increased flexibility
  • combination = board and slip; flexibility
• Qualities of the upper shoe:

  • contains midfoot control technologies
  • conforms to bony prominences
• Qualities of the midsole:

  • shock absorption rather than motion control
  • densities vary due to different sports and foot types
  • for better feel/ball control, some shoes do not have a midsole
• Materials of midsole:

  • polyurethane —> heavy runners
  • EVA (ethylen-vinyl acetate) —> shock absorption
  • compressed EVA —> increased durability
• Qualities of the outsole:

  • protective layer on bottom of shoe
  • constructed from different rubbers/materials depending on type of sport
  • protection, durability, traction, flexibility
• Heel counter:

  • stiff material
  • resists ankle motion
  • more pronation = stiffer heel counter
  • ankle collar = protect ankle and Achilles tendon
• Footwear fit:

  • measure feet at end of the day
  • do not increase length to accommodate width of foot (because this increases lever under the toes and can cause hyperextension)
  • the heel should be soft enough that it absorbs energy but does not collapse when walking/running
  • rigid (caves) foot = curved last with cushioning
  • mobile (flat) foot = straight last
• Forefoot height:

  • important for rigid/cavus foot people
  • if heel is too high, additional pressure is placed on the forefoot
  • forefoot is not designed to absorb energy
  • lower heel on shoe allows energy to be absorbed throughout the whole foot
  • look for shoe with only a slight difference in height
• Neutral cushioning:

  • for normal/neutral/high-arch foot
  • single density midsole
  • mild torsional rigidity
  • EVA cushioning —> shock absorption
  • slip and curve lasting
• Stability shoes:

  • for mild over-pronators
  • double density midsole
  • polyurethane —> stability
  • moderate/extreme torsional rigidity
  • curve and board lasting
  • what most people choose
• Motion control shoe:

  • for severe over-pronators/flat feet
  • triple density midsole
  • extreme torsional rigidity
  • midfoot control
  • board and straight lasting —> stability