Gait analysis
amb of healthy elderly: traditional view
- Older adults walk slower - Older adults are less steady - Older adults have difficulty turning (changing direction) - Older adults need to pay more attention when walking (harder to dual-task)
requirements for successful locomotion
- Progression - Stability - Adaptation
walking on level surface
- for level walking, the pattern of the gait cycle is always the same, joint angles are very repeatable - for those without pathology, every step looks like every other step
Amb and ICF
- health condition - activity = walking - participation - body function and structures - affected by personal and environmental factors
gait cycle description #2
- initial contact - loading response - midstance - terminal stance - pre swing - initial swing - mid swing - terminal swing
gait cycle description #1
- initial double limb stance (stance = foot is in contact with ground) - single limb stance - terminal double limb stance - swing
definitions of walking
- walking uses a repetitious sequence of limb motion to move the body forward while simultaneously maintaining stance stability - a method of locomotion involving the use of the two legs, alternately, to provide both support and propulsion - walking is for moving from one place to another, to go to the table for breakfast, to climb stairs to bed, to meet a friend
gait in women vs. men
- women walk more slowly - women have shorter step length - women have higher cadence
normalization in time
gait is shown in percent gait cycle (%GC) with stance before swing
loading response
• 0-10% • Objectives - Shock Absorption - Weight bearing stability - Preservation of progression (loading/weight acceptance in a manner that does not stop forward progression) • Critical Events - Restrained knee flexion - Restrained ankle plantar flexion - Hip Stabilization (keeping trunk vertical so we don't fall forward over leading foot, keep head moving smoothly through space)
initial contact
• 0-2% • Objective: Position limb to start stance • Critical event: Floor contact by heel (or toes or midfoot if pt does not land on heel)
Mid stance
• 10-30% • Objectives - Progression of limb over stationary foot - Limb and Trunk stability • Critical Events - Restrained ankle dorsiflexion - Knee extension - Hip stabilization (frontal plane)
terminal stance
• 30-50% • Objective - Progression of body beyond supporting foot • Critical Events - Heel Rise - Free forward fall of the body (unstable situation, forward foot is not yet in contact with ground but preparing for impact, weight isn't over support limb)
pre-swing
• 50-60% • still part of stance phase • Objective - Unloaded limb prepared for swing • Critical event - Knee flexion (to bring leg forward)
initial swing
• 60-75% • Objectives - Foot clearance (foot clears ground by about 5 mm when walking, that's why people stumble all the time) - Advancement of limb from trailing position • Critical events - Knee flexion - Hip Flexion
Mid swing
• 75-87% • Objective - Limb Advancement - Foot Clearance • Critical Events - Ankle Dorsiflexion - Hip Flexion
terminal swing
• 87-100% • Objectives - Complete limb advancement - Prepare limb for stance • Critical Events - Hip deceleration - Knee deceleration - Knee extension (don't need active knee extension to walk; knee will extend due to momentum) - Ankle dorsiflexion
muscles during terminal stance
• Ankle plantarflexors - Plantarflex ankle - "push-off" - more power generated at the ankle than there is at the hip during gait; difficult for amputee with prosthetic
typical older adult
• Has some pathology • Is de-conditioned • Is less active • Is more afraid (1/3 of older adults that break hip will die within year) • NO changes in gait in older adults without pathology as compared to young adults • the cause of changes in gait is not age, it is pathology - older adults are more likely to have pathology
muscles during mid swing
• Hip Flexors - Advance swing limb • nothing active at the knee in mid-swing, it is completely passive • Ankle dorsiflexors - Toe clearance
muscles during mid stance
• Hip extensors - Propulsion • Knee extensors - Prevent flexion • Ankle plantarflexors - Eccentric - stability
muscles during terminal swing
• Hip extensors - slowing hip flexion, extending knee • Knee flexors - Eccentric • Ankle dorsiflexors - Toe clearance
muscles during initial swing
• Hip flexors - Advance limb • Knee flexors - Toe clearance • Ankle dorsiflexors - Toe clearance
muscle activation patterns in older adults
• Increased co-activation (increased stiffness) - provides stabilization - if you already activated muscles, your response time is quicker; allows them to react more quickly, heightened sense of awareness - strategy to reduce degrees of freedom, makes task more simple but decreases older adult's ability to adapt
locate markers in space
• Mark Subject • Record motion • Digitize marker positions in each camera view • 3-D reconstruction
3D coordinates of markers
• Need each marker to be seen by at least two cameras • For full body analysis, this means 5-8 cameras • Cameras usually record directly to computer for analysis • Could use videotape - more processing time
marking the subject
• No markers - Most post-processing, least encumbrance on patient (Sports) • Passive Markers - More post-processing, less encumbrance on patient • Active Markers - Less post-processing, more encumbrance on patient
GAITRite system
• Sampling rate 120-240 samples per second • Mat available in lengths from 14 foot to 26 foot walkways, 3 feet wide (sensor area 2 feet wide) • Spatial resolution approximately 1.2 cm
muscles during pre-swing
• Trunk Erector Spinae - Ipsilateral side • Hip flexors - eccentric, stopping hip extension • Knee flexors - Stabilize knee • Ankle plantarflexors - Propulsion - "push-off"
muscles during loading response
• Trunk: Erector Spinae - Stabilization • Hip extensors - Propulsion • Knee extensors - Control flexion • Ankle dorsiflexors - Eccentric to prevent plantarflexion
muscles during initial contact
• Trunk: Erector Spinae - prevent forward flexion • Hip extensors - Slow progression of thigh; extend knee • Knee extensors - control knee flexion • Ankle dorsiflexors - Eccentric to prevent plantarflexion
changes in gait in older adults
• decreased cadence • decreased walking speed • decreased stride length • increased step width • increased toe out • increased stance phase • decreased joint flexion angles at the hip, knee and ankle • Trunk more rounded (shoulders extended) Most of these changes come from walking slower; find out why pt is walking slower, fix that, and these other features of their gait will also improve
gait changes with decreased speed
• decreased velocity • decreased step length • decreased cadence • decreased stride length • increased stride width • increased stance phase • increased double support time • decreased swing phase • decreased arm swing • decreased joint flexion (H,K,A)
advantages and disadvantages
• incredibly detailed record of motion, joint torques, and m. activity • based on shape of young physically fit people, not older adults, so there are errors in the model • older adults don't want to wear a bathing suit and be recorded for 2 hours
three-dimensional analysis
• mark subject • record motion • person - marker placement - 3D coordinates of markers - marker coordinate system - anthropometric measurements - estimation of joint centers - body centered coordinate system - joint angles
walkway/mat system
• measures temporal and spatial parameters of gait • quick and inexpensive • insturmented walkway with sensors embedded, computer to calculate parameters of interest
power generation in the older adult
• older adults generate less torque and less power at the ankle - reduction in muscle strength (they are weaker) - adaptive change to create less destabilization (makes amb safer) - may be a reflection of what they choose to do, not because of pathology
proactive adaptation
• see an obstacle ahead and plan ahead to get around obstacle • older adults are good at this, better than young walkers • if older adults is given a shorter time to react, not as good • walking slower gives older adults more time to adjust/adapt to obstacles - poor vision, decreased awareness of environment • worse for shortening step than for lengthening step - due to instability of gait; we want to get swing leg out in front so it is under CoM; short step is an unstable thing to do, while longer step will still keep CoM in between your base of support
slip
• slip = perturbation to stance leg; loss of traction • usually occur at initial contact (heel slip), can be dangerous - can also occur at push off (toe slip), but people don't usually fall from a toe slip • recovery: - trunk hyperextension - arm elevation (protective response) - shorten stride length - LE flexion (lower CoM) • older adults have longer onset times, lower magnitude of postural mm. activation, so they cmopensate with more UE motion, more co-activation, and slower, smaller steps • we can strengthen them, teach them adaptations, and give AD to widen BoS
reactive adaptation
• something happens to you, like a slip or a trip, and you have to recover from it
trip
• trip = perturbation to swing leg, stops forward progression of the limb, CoM is pulled backwards • to recover from a trip, you use: - hip flexors of swing leg to get foot up over obstacle - ankle plantarflexors of stance leg to try to slow forward progress, lift CoM • rate of torque development is more crucial than available strength - weakness is not main cause of problem in older adult - co-activation of mm. allows older adult to react more quickly
community ambulator
• walk 150' (which is not even enough to reach a post office) • .9-1.2 m/s
observational gait analysis
• watch them walk • videotape - gives you a permanent record - we can slow/stop motion - can show pt to help them understand the changes we want • it is systematic, readily accessible, and inexpensive
disadvantages of observational gait analysis
• without videotape, no permanent record, just observations • inexact • unreliable, even with training and practice
