Understanding Normal and Pathological Gait Flashcards
What is the definition of normal gait?
A series of rhythmical, alternating movements of the trunk & limbs which result in the forward progression of the center of gravity.
What happens as normal gait speed increases?
Gait becomes a series of controlled falls.
What is a gait cycle and when does it begin and end?
A single sequence of functions by one limb. Beginning when reference foot contacts the ground and ending with subsequent floor contact of the same foot.
What is the standard toe out angle?
7-10 degrees
What is step length?
The distance between corresponding successive points of heel contact of the opposite feet.
What is the relationship between right and left step length in normal gait?
They are equal.
What is stride length?
Distance between successive points of heel contact of the same foot.
What is normal stride length?
2 times step length
What is the walking base?
Side-to-side distance between the line of the two feet
What is another name for walking base?
Stride width, base of support
Walking base will be ______ in those with balance issues.
Larger
What is cadence?
Number of steps per unit of time
What is normal cadence?
100-115 steps/min
Does it take more energy to maintain a faster or slower gait?
slower
What is normal walking base?
3-5 inches
What is velocity?
The distance covered by the body in a unit of time
What is velocity usually measured in?
m/s
True or False: Instantaneous velocity does not vary during the gait cycle
False, It does vary
How do you calculate average velocity?
step length x cadence
What is comfortable walking speed (CWS)?
The speed that requires the least amount of energy consumption per unit of distance
What is the average CWS?
80 m/min
What are the 2 phases of gait cycle?
Stance phase and swing phase
What is stance phase?
When the reference limb is in contact with the floor.
What is swing phase?
When the reference limb is not in contact with the floor
What are the two types of support?
single support and double support.
What is single support?
Only one foot is in contact with the floor
What is double support?
Both feet are in contact with the floor
What are the parts of stance phase?
Hell contact, foot-flat, midstance, heel-off, toe-off
What are the parts of swing phase?
Acceleration, midswing, and deceleration
What percentage of gait cycle do stance and swing take up?
60; 40
What percentage of gait cycle do single and double support take up?
40;20
What happens when walking speed increases?
Stance phase decreases,swing phase increases, and double support decreases
What is running?
Walking w/out double support
What is the stance/swing ratio in running?
40;60
What happens to the support in running?
Double support disappears and ‘double swing’ develops.
Where is the body’s COG during walking?
Midway between the hips, a few cm infront of S2.
Least energy consumption if COG travels in a ________ _______.
Straight Line
What is vertical displacement?
The rhythmic up and down movement of the COG in gait.
When is vertical displacement at its lowest point? Its highest?
double support, midstance
What is average vertical displacement?
5cm
What is the path of vertical displacement?
An extremely smooth sinusoidal curve
What is lateral displacement?
The rhythmic side-to-side movement of the COG during walking
When does lateral displacement reach it’s lateral limit?
Mid stance
What is the average lateral displacement?
5cm
What is the path of lateral displacement?
An extremely smooth sinusoidal curve
What is overall displacement?
The sum of vertical and horizontal displacement
What does overall displacement of COG look like from an AP view?
A figure 8
What are the determinants of optimization in gait and what are they used for?
pel rotation; pel tilt; kn flex. in stance phase; ank mech.; ft mech.; and lat. disp. of body. Used to min. abnormal shifts of COG to reduce the energy consumption of gait.
What is optimal pelvic rotation in gait and what does it do?
Forward rotation in the horizontal plane by ~8 degrees. Reduces the angles of hip felx. and exten. Enables a longer step length w/o lowering COG.
What is optimal pelvic tilt in gait and what does it do?
5 Deg dip of swinging side in gait. In standing it’s a trendelenberg sign. It reduces the height of the apex of the curve of COG.
What is optimal kn flex. in stance phase and what does it do?
~20 deg. It shortens leg in mid. of stance phase. Reduces height of apex of curve of COG.
What does optimal ank mech in gait do?
Lengthens leg @ heel contact. Smoothens COG curve, reduces lowering of COG
What does optimal ft mech in gait do?
Lengthens leg @ toe-off as ank moves from dorsiflex to plantar flex. Smoothens COG curve, reduces lowering of COG.
What does optimal lat disp. of body in gait do?
Narrow walking base min. lat. disp. of COG. Reduces energy comsumption bc of reduced lateral acceleration and deceleration.
What forces have the most significant influence on gait?
gravity, muscular contraction, inertia, and ground reaction force (GRF)
The force that the ft exerts on the floor due to gravity and inertia is opposed by?
The GRF.
GRF may be resolved into?
Horiz. and vert. components.
Joint position and RF help with understanding what during gait?
muscle activity
What is the position of the heel at initial heel contact?
Transient
What muscles in the ankle, knee, and hip are active at heel-contact?
DF; Quad; Glut. max. & hamstrings.
What type of muscled demand does gait have?
Low, 20-25% of max muscle strength, MMT of ~3+
What are the common gait abnormalities?
Antalgic gait; Lat trunk bending; Funct leg-length discrepancy; Inc. walking base; inadeq. df control; and excessive kn exten.
What is Antalgic gait and its causes
Stance phase on affected side in short. Inc. in stance on unaffected side. causes: OA, Fx, tendinitis
What is abormal lateral trunk bending in gait and its causes?
Trendelenburg gait- unilat (Usual). Waddling gait-bilat. Causes: px in hip, hip abd wk, leg-length discrep, and abnormal hip joint
In a normal hip how is joint reaction force (JRF) calculated?
JRF up the femur = Body weight+abductor force down the femur
JRF is always ______ than body wght.
higher
What is JRF?
Force generated w/in a joint in response to forces acting on the joint.
What is JRF in the hip the result of?
The need to balance the moment arms of body wght and abd tension.
What does JRF in the hip do?
maintain a level pelvis
What are the joint reaction forces in SLR? single leg stance? walking? running?
2W; 3W; 5W; 10W
What is functional leg length discrepancy and its common compensations?
Swing leg is longer than stance leg; Circumduction, hip hiking, steppage, vaulting
What happens in abnormal inc walking base and what causes it?
walking base 5-10 cm; deformities- abd hip, valgus knee. Instability- Cerebellar ataxia, proprioception deficits
What happens in gait with inadequate df control? causes?
Stance phase- foot slap; swing phase- toe drag; causes- wk tibialis ant., spastic plantar flexors
What happens in gait with excessive knee exten. and what are common causes?
Loss of normal kn flex during stance phase; kn may go into hyper extension; genu recurvatum; causes- Quad weakness, quad spasticity, and knee flex weakness
What is genu recurvatum?
hyperextension deformity of the knee
What is the extra step in running gait?
The float when knee drive comes from hip/glutes and the rest of the leg hags relaxed
