Chapter 1 Flashcards
Factors to Consider in gait
Gait is efficient (100 calories/mile) when biomechanically sound
Complicated process a) 100 bones, 200 muscles involved
Significant involvement of pelvis and lumbar spine
Pronation
Eversion, dorsiflexion
In gait, it usually refers to movement of the calcaneus, which produces motion in the subtalar joint.
This is different than the way we use the term in posture analysis where it refers to a position of the foot.
In gait, it’s a dynamic movement. In posture, it’s a static position.
Importance in gait
A normal amount of pronation happens during gait.
An excessive amount can lead to problems.
Supination
Inversion, plantarflexion
In gait, it also usually refers to movement of the calcaneus, which produces motion in the subtalar joint.
Again, this is different than the way we use the term in posture analysis where it refers to a position of the foot.
In gait, it’s a dynamic movement. In posture, it’s a static position.
Importance in gait
A normal amount occurs during gait, but if excessive, can also lead to problems.
Phases of Gait
stance phase - weight bearing, approximately 60% of gait cycle
swing phase - toe-off to heel strike, approximately 40% of gait cycle
stance phase
heel strike
midstance
propulsive period
heel strike
(contact period)
Toe-off opposite foot
Knee extended
Foot dorsiflexed
Leg decelerating
Subtalar joint pronating throughout
Note that even though the subtalar joint is pronating (calcaneus rocking laterally), the foot itself is in a supinated position.
27% of stance phase
Major function: transfer weight and shock absorption
Note to remember:
At any given moment during the stance phase, the subtalar joint is doing the opposite of the position of the foot itself (pronation or supination).
o For example, if the foot is in a supinated position (e.g., heel strike), the subtalar joint is pronating.
midstance
Weight-bearing period between foot flat and heel lift
Toe-off completed for opposite foot
Foot in full contact with floor
40% of stance phase
Subtalar joint supinating
Note that even though the subtalar joint is supinating (calcaneus rocking medially), the foot itself is moving toward a pronated position.
Major functions:
bearing weight
convert foot from adaptive shock absorber to rigid lever for propulsion
Propulsive period
Period between heel lift and toe-off (push-off)
33% of stance phase
Subtalar supination continued and completed
Note once again that even though the subtalar joint continues to supinate (calcaneus rocking medially), the foot itself is in a pronated position.
major functions:
- transfer weight from lateral to medial side of foot, and to ball and toes for even propulsion
- shifting weight of body to other foot
Swing phase
toe-off to heel strike, approximately 40% of gait cycle
Acceleration phase
midswing
deceleration
Gait Determinants
Efficient gait has minimal vertical oscillations; additional energy is used for these vertical displacements.
Determinants are biomechanical properties which decrease vertical oscillations and allow for more efficient motion.
Normal oscillation pattern
High point: midstance (either foot)
Low point: double weight bearing (toe-off/heel strike)
Six classical determinants
Pelvic rotation
Pelvic tilt
Pelvis shift
Knee flexion
Knee-ankle relationship
Hip flexion
Pelvic rotation
Rotation of the entire pelvis away from the side of the forward leg
I.e., when the right leg is forward, the pelvis is rotated to the left.
4° to each side
Axis of rotation in the opposite hip
Result is decreased angle between leg and floor, and between hip and leg (i.e., decreased hip flexion)
Vertical displacement decreased by 3/8 “
Pelvic tilt
Pelvis dips inferiorly on the swing side (4-6°)
Opposite hip adducts (weight bearing hip)
Gluteus medius is important to prevent excessive adduction of weight bearing hip (Trendelenburg test)
Decreases vertical displacement 1/8”
Pelvis shift
Pelvis shifts toward stance side (approximately 1”)
Hip adduction on stance side
Smoothes pelvic motion, helps maintain balance
Knee flexion
Stance leg knee goes from full extension (heel strike) to 15° flexion; knee re-extends as toe-off approaches
Important shock absorber
Decreases vertical displacement 1/8”
Knee-ankle relationship
Similar to knee flexion determinant
Ankle 90° at heel strike, plantar flexion follows, then dorsiflexion as toe-off approaches
As heel raises during toe-off, vertical lift smoothed out by knee flexion
Hip flexion
Acceleration stage of swing phase
Moves foot forward with minimal vertical undulation
Would have to raise pelvis without hip flexion
Which are the prime movers of gait?
Prime movers
(1) hip flexors/extensors
Major muscles of gait
Gluteus maximus and medius
Hamstrings
Gastrocnemius and soleus
Tibialis anterior
Quadriceps
Iliopsoas
TFL
Muscle activity during Heel Strike of stance phase
heel strike
(deceleration and stabilization) (a) Hamstring activity decreases (b) Quads - extend knee (c) Gluteus medius - stabilizes pelvis, abducts hip (d) Paraspinal muscles - keep pelvis from dipping excessively (e) Tibialis anterior - dorsiflexes foot, eccentric contraction as foot makes contact
muscle activity during acceleration of swing phase
Acceleration
(a) Hip flexors (iliopsoas and quads) flex hip and accelerate forward
(b) Tibialis anterior contracts so toes clear floor
Concentric Contraction
the force generated is sufficient to overcome the
resistance, and the muscle shortens as it contracts.
Eccentric Contraction
the force generated is insufficient to overcome the resistance and the muscle lengthens as it contracts.
Muscle activity during midstance of stance phase
Midstance
(a) Body weight being pulled over foot by the body's momentum (b) Gastroc., soleus, and TFL braking and controlling (3) Toe-off (a) Propel body weight forward (i.e., upward and toward other foot) (b) Gastroc and soleus contraction
Muscle activity during Propulsion of stance phase
Toe-off
(a) Propel body weight forward (i.e.,
upward and toward other foot)
(b) Gastroc and soleus contraction
Which are the stabilizers of gait?
Stabilizers
(1) hip abductors/adductors
Which are the decelerators of gait?
Decelerators
(1) hamstrings and gluteus maximus to slow down swing
muscle activity during decelleration of swing phase
Deceleration
(a) Contraction of gluteus maximus and hamstrings decelerates and prepares limb for heel strike
What are the important aspects of physical examination of gait?
(1) Nervous system integrity
(2) Coordination and integration of movements
(3) Muscle strength and health
(4) Biomechanical integrity and stability of involved joints
What are the methods of evaluting gait?
a) Complex and difficult process to assess
b) Begin with general observation and overview
c) Break down into component parts
What are the difference causes of stance phase abnormality?
Muscle weakness
Instability
Pain
What is a gluteus medius lurch?
(i) Weak or paralyzed gluteus medius (hip abductor)
(ii) Can’t abduct hip during stance phase
(iii) Must lean toward weak involved side to center gravity over stance leg
(iv) Or may let opposite side hip sag excessively during swing phase (a) Trendelenburg Gait
What is a gluteus maximus lurch?
(i) Weak gluteus maximus (hip extensor)
(ii) Must shift pelvis anterior and thorax posterior to maintain hip extension
What is a waddling gait?
(i) Proximal lower extremity (hip, etc.) muscle atrophy, dystrophy (ii) Example: bilateral gluteus medius lurch
(iii) Feet are wide apart; walk resembles that of a duck
What is do weak quadriceps do in gait?
(i) May cause knee to buckle into flexion
What is ataxic gait look like?
(i) Characterized by staggering and unsteadiness
What does propulsive gait or festination look like?
(i) Walks on toes as though being pushed, small steps
(ii) Starts slowly, then gets faster; may need to grab something to stop
(iii) Typical of Parkinson’s disease
What is the gait presentation cerebellar instability?
(i) Cerebellum controls coordination
(ii) Reeling gait
(iii) May wander off to one side or the other
What is the presentation of gait with joint injury?
(i) Meniscal and cruciate ligament tears which lead to instability
What presentation in gait can pain cause?
Limping or antalgia
What are the two types of trauma?
Macro
Micro
What is limping gait? (include examples)
(i) Pain while weight bearing for whatever reason
(ii) Examples: Low back pain, gout, heel spurs, ingrown toenails, etc.
What is antalgia?
(i) Antalgia = anti-pain, or away from pain
(ii) Protective gait
(iii) Could be from pain anywhere in the body
What are some causes of swing phase abnormality?
Weak dorsiflexors
Hypomobile joint
Spastic paraplegia
What is the presentation of weak dorsiflexors?
Footdrop
(i) drags toes on floor when swinging the leg forward
Steppage
(i) lifts leg higher than normal so foot will clear floor
What is the presentation of a hypomobile joint (ie: hip or knee)
(a) May need to swing leg out to the side so foot will clear the floor (circumduction gait)
(b) May need to raise swinging hip higher than normal so foot will clear the floor (hip hike gait)
What is the presentation of spastic paraplegia (scissors gait)
(a) Legs cross the midline
(b) Bilateral contractural changes (adductors)
(c) Partial paralysis - must swing leg out in front without muscular assistance
