1
Q
Six Determinants of Gait
A
- States that energy costs during gait (vertical & horizontal displacements) is minimized by six actions of the pelvis, hip, knee, & ankle.
- Sagittal plane: hip and knee flexion, knee and ankle flexion
- Transverse Plane: Pelvic rotation
- Frontal Plane: lateral pelvic tilt
- Premise 1: gait is the translation of the COM through space along a pathway requiring the least expenditure of energy
- Premise 2: Minimizing the amount that the body’s COG is displaced from the line of progression is the major mechanism for reducing the muscular effort of walking, & consequently, saving energy.
- Based upon Gait Kinematics: study of motion of mechanical points of joints during upright mobility Involves:
1. extent of joint movement (ROM)
2. Speed (velocity of body & limbs
3. Direction (joint motion: flex, ext) - classifies two major phases: stance, swing
- Phases indicates specific phases in cycle
- each joint shows “normative data” for an adult
2
Q
Inverted Pendulum Theory
A
- States that the stance leg is kept relatively straight during single support, functioning like an inverted pendulum
- COM, located near the hip, travels in a series of arcs prescribed by each single support phase. The limb travels like a pendulum, thus does not require much energy.
3
Q
Gait is measured by
A
- m/s
- age
- sex
- level of community access
to determine health status
4
Q
Functional ambulatory terms in rehab (with or w/o assisted device)
A
- safely crosses the street (1.3 m/s)
- community ambulation (going to the store, has to adapt)
- limited community ambulator (maybe due to pain, 1 or 2 blocks)
- household ambulator
- dependent ambulator (requires assitance of a person)
5
Q
Preferred Gait Speed and Slow and Fast Speeds
A
- a person’s normal comfortable speed of gait may be referred to as preferred, natural, self-selected, or free. When assessing gait note that the gait is self selected or preferred gait speed.
- slow and fast speeds of gait refer to speeds slower or faster than a person’s normal comfortable walking speed, designated in a variety of ways
6
Q
Gait velocity indicates…
A
- function, falls, and requirement for specialized skill care
- Gait speeds:
- > 1.0 m/s: predictive of completing yard work, climb flights of stairs
- < 1.0 m/s: benefit from fall prevention, >0.67 to complete self care, >0.89 for household activities
- < 0.60 m/s: predicts future risk of falls and hospitilization, tends to require assitance with ADL and IADLs, >0.49 to cross street
- < 0.40 m/s: lomger length of stay in acture care, likely d/c to skilled nursing, inpatient rehab, or nursing home setting or home health services
- Use 10 m walk test to measure gait velocity
7
Q
Gait cycle (2 phases)
A
- Stance phase: during a walking cycle, a given foot is in contact with ground, heel strike to toe off, 60%
- Swing phase: during the walking cycle, a given foot is not in contact with ground, 40%
- 20% is double support, 80% single support
8
Q
Double & Single Support
A
- There are two periods of double support occuring between the time one limb makes intial contact and the other one leaves the floor at toe off
- At normal walking speed, each period of double support occupies about 11% of gait cycle, which makes approx, 22% for a full cycle.
- The body is thus supported by only one limb for nearly 80% of cycle. The approx. value of 10% for each double support phase is usually assigned to each of the double support periods.
9
Q
Gait Spatial & temporal parameters
A
Foundational: step & stride length (spatial), step& stride length are equal bilaterally
Stride length: is the typical measure used in gait analysis
Gait cycle:right initial contact to right initial contact
10
Q
Spatial parameters
A
- Step length:calcaneus to contralateral foot calcaneus
- Stride length: calcaneus to calcaneus of ipsilateral calcaneus, 0.67 m women, 0.76 m men
- Step width: mid point of calcaneus to mid point of calcaneus
- Foot angle: toes pointed out
- measured in m
- Step and stride length is a critical measure in PT. The longer your step or stride length the more ground you’ll cover!
- Determinants of stride length: age, height, males>, injury/illness
11
Q
Gait Temporal Parameters
A
- Number of steps per min (cadence): normal 80-90 steps per min in adults
- Swing time or stance time (secs)
- Gait velocity essential for PT (age, six determinants), 1.2-1.4 m/s for adults
12
Q
Clinical application
A
- PTs use several important measures
- Gait velocity: in all settings determines discharge preferences, intervention outcomes
- stride length: injuries (orthopedic), neurological clients
- level of community ambulation
13
Q
Calculation of Gait Measures
A
- Calculation of Gait velocity (gait velocity=cadence x stride length)
- Example: cadence of 80 steps per min x 0.9 m (stride length) =0.72 m/s (move decimal point to left two times to account for seconds)
- Cadence= # of steps taken by person per unit of time. Cadence is measured per min
- A shorter step length will result in an increased cadence at any given velocity
- A longer step length will result in a decreased cadence at any given velocity
