Lecture 1 (Gait Theory, Velocity, Cycle, Temporal Parameters) Flashcards
What are the two theories of gait?
Six determinants of gait and inverted pendulum
What does the six determinants of gait theory follow?
Kinematic theory
What does the six determinants of gait hypothesize?
Energy expenditure during gait (horizontal and vertical displacements) is minimized by the 6 actions of the pelvis, hip, knee and ankle
What are the 6 major gait features? Which planes?
Sagittal:
Hip and knee flexion
Knee and ankle flexion
Transverse:
Pelvic rotation
Frontal:
Lateral pelvic tilt
What does pelvic rotation affect?
Stride length; more rotation = longer stride and vice versa
Which sex experiences a more noticeable pelvic tilt when walking? Why?
Females b/c their glute med is susceptible to be weak
What is gait kinematic?
Study of motion of mechanical points of joints during upright mobility
What does gait kinematic involve?
Extent of joint movement (ROM), speed, direction (joint motion)
What are the two major phases in the 6 determinant theory?
Stance and swing phase
What does the inverted pendulum theory state?
Stance leg is kept relatively straight during single support, functioning like inverted pendulum
How does the COM differ between the two theories?
6 determinant: reduced COM displacement, stays in a straight line
Inverted pendulum: COM travels in a series of arcs
What act as the “propellers” during the push/toe off?
Gastroc and soleus
What is gait speed measured in? What are normative values based on?
Meters/sec; age and sex
What are the functional ambulatory terms for rehabilitation medicine?
-Safely cross the street (1.3 m/s)
-Community ambulation
-Limited community ambulator
-Household ambulator
-Dependent ambulator (requires assistance of a person)
How can you describe someone’s normal comfortable speed of gait?
Preferred, natural, self-selected, free
What’s the ideal walking speed for better outcome? What speed increases risk of falls etc?
1.0 m/s; 0.7 m/s
What is stance phase? What % of gait cycle?
When a foot is in contact w/ the ground, heel-strike to toe-off; 60% of gait cycle
What is the swing stance? What % of gait cycle?
Foot is not in contact w/ ground; 40%
What % in a full gait cycle does a double support occur?
22%
What are the spatial parameters?
Step length, stride length and step width
What is step length?
Calcaneus to contralateral foot calcaneus
What is stride length?
Calcaneus to calcaneus of ipsilateral calcaneus
What is step width?
Mid point of calcaneus to midpoint of calcaneus
How does foot angle affect gait?
Wide foot angle can decrease stride length
What are the critical foundational measures in PT?
Step and stride length
What are the determinants of stride length?
Age, injury/illness, height, sex (males>)
What is cadence? What is normal range for adults?
of steps per minutes; 80-90 steps/min
How to calculate gait velocity
Cadence x stride length
How does a shorter and longer step length affect cadence?
Shorter -> increased cadence
Longer -> decreased cadence
