3D gait analysis Flashcards
what is movement analysis?
systematic study of how the human body moves
compare neural vs mechanical contraints
1.neural constraints related to the ability of the brain and spinal cord to process sensory input, generate motor commands, and coordinate complex muscle actions.
2. Mechanical Constraints
refer to physical limitations in the body that affect movement. These are related to the structure, flexibility, and range of motion of muscles, joints, and bones, as well as the interaction between these tissues during movement.
what are the different options for gait and mvt analysis?
-observational - overground or on treadmill
-video analysis - using software
-temporal spatial analysis - stopwatch and measured track
-instrumental analysis - 3D movement analysis of kinematics
what are some challenges to analysing gait by observation?
-fast movement
-multiple joints & degrees of freedom - cant accurately assess 3 planes with a 2D video
-eye is naturally drawn to the segment with the largest displacement eg foot
what are the key points to observe while watching someone walk?
-initial contact
-loading response - knee flex and PF
-midstance - pelvis level and knee extension
-terminal stance - ankle DF, heel rise and hip ext
-pre swing - ankle DF
-initial / mid swing - ankle DK, knee flexion
-terminal swing - ankle DF. knee ext
what are the advantages of video movement analysis?
-can freeze frame at key points in gait cycle
-avoids patient getting tired while clinical observes
-software can help tracking of key points
-outcome measure for recording progress
what are examples of disadvantages of video movement analysis?
-2D
-sensitive to error of parallax (when an object looks different depending on where you’re standing or looking from)
what are technical requirements for video?
-lighting
-brightness
-contrast
-space
-walkway length
-background
-camera alignment
what are examples of temporal-spatial parameters “vital signs” of gait?
-time
-distance
-speed (m/s)
-cadence (steps/min)
-stride length (metres)
how to calculate speed, cadence and stride length for this case:
10m timed walk test - Mary is timed at 12 s and takes 22 steps
speed: 10/12= 0.83m/s
cadence - 22/ (12/60)= 110 steps per min
stride length = 10/(22/2) = 0.91m
why should we measure walking speed?
- it is recommended as a clinical vital sign
-global indicator of MSK, neurological and cardiovascular health
what are examples of commonly used outcome measures to measure walking speed?
-TUG
-10m walk test
-6 minute walk test
what activity are slow gait speeds associated with?
-reduced ADL performance
what does 3DGA involve?
-involves placing small reflective markers on bony landmarks to track movement
-gathers kinematic data - this refers to the analysis of body movements eg joint angles, stride length and walking speed etc
-kinetic data - looks at the forces that cause movement such as the force that the feet generate when they hit the ground (ground reaction force)
-EMG to measure muscle activity
what is kinematics?
kinematics is the study of how the body moves without considering the forces that cause the movement
-it looks at joint angles, step length , walking speed
what is kinetics?
kinetics focuses on the forces generated to cause or change movement
eg looks at ground reaction forces, muscle forces
what are examples of advantages of 3DGA?
-highly sensitive and reliable
-improves decisions
-better outcomes
when is 3DGA indicated?
-good for research
-for paediatric orthopaedic surgery
-diagnosis of gait disorders
-complex movement problems - fine tuning rehab in sports
what is plantar pressure analysis?
the measurement of plantar pressure and force distribution during standing and walking
-can use a force plate and in shoe sensors
why is plantar pressure analysis useful?
-to measure foot shape and position
-to identify pressure areas needing relief
what is surface electromyography?
a muscle activation measuring tool- detects ions across the sarcolemma ie depolarisation
-useful for confirming, rejecting hypothesis about motor behaviour and exercise prescription
