Foot and Ankle Biomechanics
in Athletic Injuries
2003 World Exercise Professionals Symposium
KACEP 4th Annual Meeting
Daejeon, KOREA
KyungMo Han, PhD., ATC
California State University
Dominguez Hills
Introduction



Anatomy of the foot and ankle
Biomechanics of the foot and ankle
Athletic injuries of the foot and ankle
Bone of the
Foot

28 bones
(26 +2)

14 phalanges
5 metatarsals
7 tarsals

2 sesamoids


Plantar Flexion







Gastrocnemius
Soleus
Plantaris
Peroneus Longus & Brevis
Tibialis Posterior
Flexor Hallucis Longus
Flexor Digitorum Longus
Dorsiflexion




Tibialis Anterior
Extensor Digitorum Longus
Extensor Hallucis Longus
Peroneus Tertius
Inversion, Adduction and Supination





Tibialis Posterior
Tibialis Anterior
Flexor Digitorum Longus
Flexor Hallucis Longus
Extensor Hallucis Longus
Eversion, Abduction and Pronation




Peroneus Longus
Peroneus Brevis
Peroneus Tertius
Extensor Digitorum Longus
Arches of the Foot




Anterior metatarsal arch
Transverse arch
Medial longitudinal arch
Lateral longitudinal arch
Articulations




Forefoot
 Metatarsophalangeal (MTP) Joint
 Proximal interphalangeal (PIP) Joint
 Distal interphalangeal (DIP) Joint
Midfoot
 Tarsometatarsal (Lisfranc) Joint
Hindfoot
 Subtalar Joint
Midtarsal Joint
Single Plane Movements



Inversion/Eversion
 Frontal plane (X axis)
 The foot twists inward and upward
Abduction/Adduction
 Transverse plane (Y axis)
 The foot rotates laterally and medially
Plantar flexion/Dorsiflexion
 Sagittal plane (X axis)
 The foot moves upwards and downwards
Tri-Plane Movements

Supination
Inversion
 Plantar flexion
 Adduction


Pronation
Eversion
 Plantar flexion
 Adduction

Supination of the Subtalar Joint
(Open Chain: NWB)

Talus


Neutral
Calcaneus



Inverts
Adducts
Plantar flexes
Pronation of the Subtalar Joint
(Open Chain: NWB)

Talus


Neural
Calcaneus



Everts
Abducts
Dorsiflexes
Supination of the Subtalar Joint
(Closed Chain: WB)

Talus




Moves lateral
Externally rotates
Dorsiflexes
Calcaneus

Inverts
Pronation of the Subtalar Joint
(Closed Chain: WB)

Talus:




Moves medially
Internally rotates
Plantar flexes
Calcaneus

Everts
Subtalar Joint

ROM: 20 degrees (inversion) & 5 degrees (eversion)

Accessory motions:
 Convex portion of calcaneus glides laterally with
inversion
 Convex portion of calcaneus glides medially with
eversion

Open pack position: subtalar joint neutral
Closed pack position: full supination

TRIPLANAR MOTION
Longitudinal Midtarsal Axis



9 degrees from
the sagittal plane (X axis)
15 degrees from the
transverse plane (Y axis)
Primarily provides Z axis, Frontal
plane motions
 INVERSION/EVERSION
 ABDuction/ADDuction
 dorsiflesion/plantar flexion
Oblique Midtarsal Axis



57 degrees from the sagittal plane
(X axis)
52 degrees from the transverse
plane (Y axis)
Therefore, primarily provide X & Y
axes, sagittal & transverse plane
motions
 DORSI flexion/PLANTAR
flexion
 ABDuction/ADDuction
 inversion/eversion
Compressive Forces of the Foot
(60 lb of load applied to the talus)
Weight Distribution
(Barefoot standing)
Deltoid Ligament Stress
(Average of 14 degrees of valgus talar tilt)
Deltoid Ligament
Stress





LS: talar lateral shift
AS: anterior shift
TT: valgus talar tilt
DD: deep deltoid
SD: superficial deltoid
Ankle Joint
Stability

The superficial and deep
deltoid ligaments are
responsible for resistance
to eversion and external
rotation stress
Mechanisms of Inversion Sprain



The mechanism of lateral ankle sprains involves a
combination of sudden uncontrolled plantar flexion
and inversion at the beginning of the initial contact of
the foot with even or uneven surfaces
This causes unexpected inversion torque to the ankle
joint
An ankle sprain occurs when this torque is applied at
a rate that exceeds the minimum time necessary for
the neuromuscular system to respond
Ankle Joint Stability


The ATF and CF ligaments
forms a 105 degrees angle
with one another
ATF



Resists ankle inversion and
plantar flexion (resists to
anterior talar displacement and
internal rotation of the talus)
Greatest tension in PF
CF


Resists ankle inversion and
dorsiflexion (contributes the
subtalar joint stability)
Greatest tension in DF
Peroneus Longus Latency
Peroneus Longus
Platform
Ankle
Ankle
1.2
1.0
0
Inversion Platform
0.8
-20
0.6
Compute Mean and SD
of 100 ms before
Platform Drop
0.4
10 SD
above Mean
-40
0.2
0.0
-60
0
50
100
150
Time (ms)
200
250
Angle (Deg)
Peroneus Longus EMG (mV)
PL EMG
Flat Feet/Fallen Arch
(Pes Planus)


Associated with excessive pronation, forefoot varus,
wearing tight shoes (weakening supportive structures)
being overweight, and excessive exercise placing
under stress on arch
Excess pronation causes the foot’s arch to collapse &
elongate giving the appearance of a flat foot
High Arch
(Pes Cavus)



Associated with excessive supination, accentuated
high medial longitudinal arch
Poor shock absorption resulting in metatarsalgia,
foot pain, clawed or hammer toes
Associated with forefoot valgus, shortening of
Achilles and plantar fascia
Achilles Tendonitis

Inflammation of the achilles tendon

Commonly occurs from shearing and tractional
placed on the achilles tendon at the back of the heel

The foot accelerates into an excessively pronated
position and the calcaneus is everted
An increase in medial tendo-achiulles traction
Results in transverse shearing of the tendon and
sheath


Plantar Fasciitis




Excess subtalar joint pronation lowers the arch
Places a traction force on the plantar fascia
Inflammation of the fascia and surrounding tissues
 causing pain in the arch and heel
Chronic traction  development of a bony growth
on the calcaneal tuberosity  “heel spur”
Jones Fracture

Caused by inversion and plantar flexion, direct
force (stepped on) or repetitive trauma

Most common = the base of 5th metatarsal
Hallux Valgus
(Bunion)


Exostosis of 1st metatarsal head;
associated with forefoot varus;
shoes that are too narrow,
pointed or short
Bunionette (Tailor’s bunion)
impacts 5th metatarsophalangeal
joint - causes medial
displacement of 5th toe
Turf Toe
(1st metatarsophalangeal joint sprain)


Hyperextension (or hyperflexion) injury resulting
in sprain of 1st metatarsophalangeal joint
May be the result of single or repetitive trauma
during push off in walking, running, and jumping
Other Athletic Injuries

Injuries to the tarsal region







Fracture of the talus or calcaneus
Apophysitis of the calcaneus (Sever’s Disease)
Retrocalcaneal bursitis (Pump Bump)
Heel contusion
Cuboid subluxation
Tarsal tunnel syndrome
Tarsometatarsal (fracture) dislocation
Other Athletic Injuries

Injuries to the metatarsal region






Longitudinal arch strain
Metatarsal stress fractures
Sesamoiditis
Metatarsalgia
Morton’s Neuroma
Injuries to the toes






Sprained toes
Fractures and dislocations of the phalanges
Morton’s toe
Hallux Rigidus
Hammer toe, Mallet toe or Claw toe
Overlapping toes