1. Selecting Running Shoes
Injury Prevention and Performance Enhancement

2. Biomechanics Laboratory, School of Human Kinetcs
Shoe Anatomy
sole: bottom of shoe
insole: interior bottom of a shoe
some models have removable insoles
outsole: material in direct contact with ground (tread)
midsole: material between insole and outsole (made of EVA or PU)
upper: top of shoe that holds shoe to foot
Low-cut, mid-cut and high-cut uppers
toe box: area that holds toes and heads of metatarsals
vamp: material over the instep
heel counter: specialized area at heel that is relatively rigid in running shoes
last: form for shaping shoe (straight, semicurved, curved) and footprint
Biomechanics Laboratory, School of Human Kinetcs

3. Forces during Walking vs. Running
long duration
double “active” peaks
+/-20% body weight
running/sprinting/jumping:
brief durations
single “active” peak
3 times BW
heel-toe landing
landings:
brief duration
up to 10+ times BW
forefoot landing
active peaks
Biomechanics Laboratory, School of Human Kinetcs

4. Why Does Running Cause Injuries?
ground reaction forces are high (3x body weight)
impact is brief therefore little time for muscles to dissipate forces
some people’s anatomy may predispose injury (leg length discrepancy, excessively pronated/supinated feet or varus/valgus knees)
running surfaces are rigid (roads, sidewalks, frozen earth)
people tend to over-train (amount per day, no recovery days)
warm-up and stretching are often neglected
Biomechanics Laboratory, School of Human Kinetcs

5. Biomechanics Laboratory, School of Human Kinetcs
Running Injuries
plantar fasciitis
anatomical, excessive heel impacts, poor running mechanics
heel spur, hammer toes, bunions
poor shoe fit
ankle and foot sprains
mechanically caused by landing off balance or on an obstacle
tibial stress syndrome/fracture
overuse injury, training on hard surfaces, old or poor footwear
knee/back pain
anatomical differences (leg length, abnormal Q-angle)
shin splints
mechanically caused by rapid changes in training surfaces and overuse
Biomechanics Laboratory, School of Human Kinetcs

6. Biomechanics Laboratory, School of Human Kinetcs
Purposes of Shoes
protection from:
sprains (high cut shoes may help but reduce flexibility)
cuts and abrasions (strong uppers may increase weight and decrease mobility)
punctures from nails, rocks, slivers etc. especially for road running (thick soles help but reduce efficiency)
traction or prevent slippage
tread helps especially on wet surfaces
spikes and studs (check rule books)
cushioning
in midsoles (reduces efficiency)
ventilation
air circulation, water drainage or waterproof?
Biomechanics Laboratory, School of Human Kinetcs

7. Biomechanics Laboratory, School of Human Kinetcs
Cut of Uppers
low cut
greatest mobility
mid cut
high cut
may help to control ankle sprains
Biomechanics Laboratory, School of Human Kinetcs

8. Biomechanics Laboratory, School of Human Kinetcs
Running Shoe Types
Cushion:
for high-arch feet, underpronator
extra cushioning in the midsoles to help absorb shocks; their soles have a curved or semicurved shape (last) that promotes a normal running motion
Motion control:
for flat feet or feet that pronate after landing
straight last and a more rigid midsole than other running shoes, these help keep your feet properly aligned.
Stability:
for normal or neutral feet
semicurved last, but the less rigid midsoles allow feet to strike the ground naturally
Biomechanics Laboratory, School of Human Kinetcs

9. Biomechanics Laboratory, School of Human Kinetcs
Cushioning
measured by durometer (hardness)
mainly in midsole
cushioning is helpful for hard surfaces
especially as muscles start to fatigue
greater cushioning means less efficiency
may cause ankle instability and sprains
gel or air cushions cause landing instability
cushioning columns are better
breaks down over time
impact testing for endurance
Biomechanics Laboratory, School of Human Kinetcs

10. Biomechanical Efficiency?
all shoes absorb and dissipate energy
cushioned running shoes absorb the most energy
the greater the cushioning the more lost energy
sprinters’ shoes have the least cushioning and are therefore the more efficient
bare feet are most efficient but traction may be compromised and they offer little protection from stones, heat or sharp objects
Biomechanics Laboratory, School of Human Kinetcs

11. Biomechanics Laboratory, School of Human Kinetcs
Athletic Shoe Types
basketball/volleyball
sturdiest with thick midsole cushioning
for wooden floors and high impacts
cross-trainers
most versatile athletic shoes available
less cushioning
spiked for track & field
greatest traction on rubberized tracks
lightest and fastest
studded for soccer or rugby etc.
greatest traction of grass or artificial turf
Biomechanics Laboratory, School of Human Kinetcs

12. Pronation versus Supination
of hand:
one-dimensional rotation
turning palm upwards is supination, downwards is pronation
of foot
three-dimensional motion
inversion, plantiflexion and internal rotation
supination is turning foot so that plantar surface (bottom of foot) is directed medially (towards midline)
pronation is turning foot so that plantar surface (bottom of foot) is directed laterally (away from midline), this is most common motion when a foot lands during running
Biomechanics Laboratory, School of Human Kinetcs

13. Supinated Foot Pronates during Landings
foot is supinated at landing pronates during loading
orthotics help to reduce rates of pronation during landings (Bates et al. 1979; Mündermann et al., 2003; Stackhouse et al., 2004) but it is unclear how they affect the kinetics (MacLean et al., 2006)
Biomechanics Laboratory, School of Human Kinetcs

14. Orthoses and Orthotics
orthosis
device added to support an anatomical structure
i.e., brace or wedge
e.g., custom foot orthotic (CFO) appliances (“orthotics”), ankle-foot orthoses (AFO) and knee braces
Biomechanics Laboratory, School of Human Kinetcs

15. Foot Orthotic Appliances
orthotic with medial forefoot post
for forefoot supination (varus)
orthotic with lateral forefoot post
for forefoot pronation (valgus or
plantiflexed first ray)
orthotic with medial heel post for
subtalar varus
Biomechanics Laboratory, School of Human Kinetcs

16. Biomechanics Laboratory, School of Human Kinetcs
References
Bates B et al. Amer J Sports Med 7: ,1979.
Huberti HH & Hayes WC. J Bone Jnt Surg 66A: ,1984.
Insall J, Falvo KA & Wise DW. J Bone Jnt Surg 58A:1-8,1976.
MacLean C, McClay Davis, I & Hamill J. Clin Biomech 21: ,2006.
Mündermann A et al. Clin Biomech 18: ,2003.
Stackhouse CL, McClay Davis, I & Hamill J. Clin Biomech 19:64-70,2004.
Biomechanics Laboratory, School of Human Kinetcs

17. Biomechanics Laboratory, School of Human Kinetcs
Knee (Genu) Valgus
valgus: outward angulation of the distal segment
distal segment is rotated Laterally
distal means farther away from the body’s centre
“knock-kneed”
common in women
Biomechanics Laboratory, School of Human Kinetcs

18. Biomechanics Laboratory, School of Human Kinetcs
Knee (Genu) Varus
inward angulation of the distal segment
“bowlegged”
common in horse riders
Biomechanics Laboratory, School of Human Kinetcs

19. Quadriceps-angle or Q-angle
“quadriceps-angle” is formed in the frontal plane by two line segments:
from tibial tubercle to the middle of the patella
from the middle of the patella to the anterior superior iliac sine (ASIS)
in adults is typically 15 degrees
Increases or decreases in the Q-angles are associated with increased peak patellofemoral contact pressures (Huberti & Hayes, 1984).
Insall, Falvo, & Wise (1976) implicated increased Q-angle in a prospective study of patellofemoral pain.
Biomechanics Laboratory, School of Human Kinetcs

20. Biomechanics Laboratory, School of Human Kinetcs
Prostheses
prosthesis
device that replaces an anatomical structure
i.e., an artificial limb
e.g., solid-ankle, cushioned-foot (SACH) foot, FlexFoot, C-knee, Mauch leg
Biomechanics Laboratory, School of Human Kinetcs

21. Biomechanics Laboratory, School of Human Kinetcs
Sprinting Prostheses
LAUSANNE, Switzerland -- Double-amputee sprinter Oscar Pistorius won his appeal Friday and can compete for a place in the Beijing Olympics.
Olympic Rule: For the purpose of this Rule the following shall be considered assistance, and are therefore not allowed:
e) use of any technical device that incorporates springs, wheels or any other element that provides the user with an advantage over another athlete not using such a device.
It's a great day for sport. I think this day is going to go down in history for the equality of disabled people.
-- Oscar Pistorius
Biomechanics Laboratory, School of Human Kinetcs