The document discusses biomechanics of walking and famous cases of Achilles tendon ruptures. It covers the aim of walking, phases of the gait cycle including stance and swing phases, movement of the main joints and muscles involved. Common gait problems like antalgic and high steppage gaits are described. Famous cases of Achilles ruptures are mentioned, including George Clooney rupturing his left Achilles tendon while filming the movie Troy in 2000. The document provides information on walking biomechanics and tendon injuries for medical students.

1. Obaje Godwin Sunday
AE-FUNAI
obaje199@gmail.com, +2348068638121
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2. Walking and Weight-bearing
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3. Biomechanics of Gait (Walking)
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4. General Outline…
 Aim of walking
 Foot on the Ground and Walking
 Movement (Running)
 Major Joints in the Foot during walking
 Muscles involved In Walking
 Gait Patterns
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5. At the end of this lecture:
Explain with the knowledge of biomechanics of
gaits and tendon in the scenario of George Clooney,
leading actor and sexiest man who ruptured his left
Achilles tendon in 2000.
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Classroom questions to
400l Basic Medical
Students at AE-FUNAI
from classes of
Biomechanics and Forensic
Medicine

6. Aim of Walking
 To move the body forward and backward. It is
towards a desired location speed and direction.
 To use energy. The body does this by moving in
straight line. Sufficient energy is generated through
up and down movement
 To cause least amount of pain for people with
painful foot conditions. Our brains have a variety of
strategies for achieving this goal, including putting
less pressure on a painful foot, or alternating the
foot's position when we walk to limit discomfort.
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7. Aim of Walking Cont’D
 The foot itself act as a shock absorber for dispersing
the force of the body as it lands.
 To form a rigid lever toward the end of the phase of
gait where the foot is on the ground, in order to
provide a way to propel the body forward.
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8. Foot on the Ground
 Have a think of what happens to each foot when we
walk. There are two phases/stages: Stance phase and
Swing phase
 Stance phase is the time when the foot is on the
ground. It comprises about 60% of the walking
cycle. Here, both feet will be on the ground for a
period of time.
 Swing Phase is when one foot is on the ground and
one in the air. The foot that is in the air is said to be
in the "Swing" phase/stage of gait.
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9. Foot on the Ground
 When the foot is on the ground while walking, there
are five sub-stages that a single foot undergoes as:
Heel strike, Early flatfoot, Late flatfoot, Heel rise,
and Toe off.
 Heel Strike
 The heel strike stage: The moment when the heel
first touches the ground and lasts until the whole
foot is on the ground.
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10. Foot on the Ground
 Early flatfoot: The moment that the whole foot is on
the ground. It occurs when the center of gravity in
the body passes over top of the foot.
 Note that the center of gravity is located
approximately in the pelvic area in front of the lower
spine when we stand and walk.
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11. Foot on the Ground
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12. Foot on the Ground
 The main purpose of this stage is to allow the foot to
serve as a shock absorber. This helps to cushion the
force of gravity on the body.
 Late flatfoot
 When the center of gravity of the body has passed in
front of the neutral position the person entered the
late flatfoot stage.
 It ends when the heel lifts off the ground. Here, the
foot needs to go from being a flexible shock absorber
to being a rigid lever that move the body forward.
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13. Foot on the Ground
 Heel rise
 Here, the foot functions as a rigid lever to move the
body forward. There is a force that goes through the
foot and is 2-3x a person's body weight. The reason is
because the foot creates a lever arm that serves to
magnify body weight forces.
 Given these high forces and considering that the
average human takes 3000-5000 steps per day (an
active person commonly takes 10,000 steps/day).
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14. Foot on the Ground
 This why the foot can easily develop chronic
repetitive stress-related conditions such as:
metatarsalgia, bunions, tibial tendon dysfunction ,
peroneal tendonitis and sesamoiditis .
 Toe off
 This begins when the toes leave the ground. Here,
the swing phase is also initiated.
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15. Running
 The basic difference between walking and running.
When running, is the time both feet are off the
ground (the "float" phase).
 It is also the period of greater speeds.
 The forces that go through the foot when it lands can
be substantially greater than during walking. It is 4-
5x body weight during running. It is more during
sprinter (6-7x body weight).
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16. Movement of the Main Joints in
Walking
 Ankle joint and the transverse tarsal joint. The
transverse tarsal joint is made up of several joints
like talo-navicular and calcaneo-cuboid joints.
 Ankle Joint
 Help the foot to move up (dorsiflexion) and down
(plantarflexion). It is assisted by two muscular
compartments in the anterior and posterior of the
leg as: anterior muscle compartment for upward
movement and posterior compartment to pull the
foot back down.
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17. Movement of the Main Joints
During Walking
 Transverse Tarsal Joint
 There are talo-navicular, calcaneal cuboid joint and
subtalar joints. The subtalar joint allows the foot to
have some side to side motion.
 The transverse tarsal joint can loosened in the early
flatfoot stage and opened in the late flatfoot and
heel rise. This is the mechanical activities at certain
points in the walking cycle.
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18. Movement of the Main Joints
During Walking
 The transverse tarsal joint is loose when the joint
axes of the two joints involved are parallel to each
other.
 When the two joint axes are not parallel, the
transverse tarsal joint becomes rigid and prevents
movement through the joint (late flatfoot and heel
rise).
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19. Movement of the Main Joints
During Walking
 The locking and unlocking of this joint is very
important to a normal gait cycle. When the heel hits
the ground, the ankle joint is lowered gently onto
the ground and the transverse tarsal joint is locked.
 In the early flatfoot, the transverse tarsal joint
unlocks, allowing the foot to become floppy and
movement is allowed. This action allows the foot to
serve as a shock absorber.
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20. Movement of the Main Joints
During Walking
 As the center of gravity passes over the neutral
position, the posterior tibial tendon pulls on this
joint and locks it, once again creating a rigid lever.
 Here, the heel rises off the ground and the calf can
channel force into the ground to propel the body
forward.
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21. Movement of the Main Joints
During Walking
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22. Muscles Work During Walking
 Heel Strike - Early Flatfoot
 The anterior compartment is most active.
 Tibialis anterior muscle, the extensor hallicus
longus, and the extensor digitorum longus lower the
foot onto the ground.
 If these muscles do not work, the foot will tend to
slap onto the ground. Here, it is clinical and called
foot drop.
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23. Muscles Work During Walking
 Late Flatfoot - Heel Rise
 Here, there is contraction of the posterior
compartment muscles against the cater of gravity on
the body. This contraction of the calf muscle serves
to control the body movement as it goes forward so
that the body does not fall forward.
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24. Muscles Work During Walking
 During late flatfoot, the calf muscle is strongly
contracting and lengthening. This is called an
"eccentric" muscle contraction. It serves to generate
an extraordinary amount of internal force within the
calf muscle and Achilles tendon.
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25. Muscles Work During Walking
 This is why most Achilles tendon ruptures and calf
tears occur during this stage gait.
 Heel Rise - Toe Off
 Here is concentric contracture of the calf muscle.
Meaning, there is continuous shortening rather than
lengthening performing
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26. Gait/Walking Problems
 Antalgic Gait or painful walking
 Sign: reduced amount of time spent in the stance
phase.
 This is because people do not want to spend any
more time than necessary on a foot that is causing
them pain. In a painful foot will spend less time on
the injured foot of only 20-30% of their gait than
50%.
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27. Gait/Walking Problems
 Sign: decreased stride length from patients not
wanting to push off from their painful foot as
powerfully as normal.
 Here, one stride tends to be longer than the other.
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28. Gait/Walking Problems
 High Steppage Gait
 This form of walking is seen in patients whose
anterior compartment muscles do not function
normally for instance, patients with a drop foot.
 This lack of anterior muscle compartment
functioning causes the foot to slap onto the ground
during the heel strike phase of walking.
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29. Gait/Walking Problems
 Patients normally respond to this problem by
bending their knee more than normal during the
swing phase of gait to lift the foot higher off the
ground.
 Treatment: fit the patient with an AFO (Ankle Foot
Orthosis) , which is a rigid brace that keeps the foot
locked in a 90 degree angle.
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30. Famous Achilles Ruptures
 Someone hit me on the back of the leg. People often
say when they rupture their Achilles tendon. The
Achilles is the strongest tendon in the body. It begins
as an extension of the calf muscle and inserts into
the heel bone/calcaneus.
 Rupturing the Achilles tendon often occurs during a
sudden dynamic movement to change directions
E.G. Basketball, tennis and squash. It is a pretty
common injury for people usually men in their 30-50
years.
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31. Famous Achilles Ruptures
 Former US Vice President (1993-2000) and Nobel
Peace Prize (2007) winning environmentalist
ruptured his left Achilles playing pick-up basketball
with members of the US House of representatives in
1994.
 Oscar winning actress Dame Judi ruptured her
Achilles in 1981 while rehearsing for the role of
Grizabella in the West End debut of the musical
CATS. As a result of the injury the part was given to
Elaine Paige of EVITA fame.
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32. Famous Achilles Ruptures
 George Clooney leading actor and sexiest man alive
(1995-2000) ruptured his left Achilles tendon in the
movie Troy.
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