Kinematics
Describing the
motions of the body parts
relative to each other during the different phases of gait
Concerned with motion of bodies without regard for the forces acting to produce the motion
Kinetics
Concerned with
forces acting on the body parts
External forces- forces exerted by the pull of gravity
Internal forces- forces exerted by muscular contraction
weight acceptance
initial contact
loading response
mid stance
Three functional tasks are achieved during these eight gait phases:
-Weight acceptance in early stance
-Single Limb Support from Midstance to Terminal Stance
-Limb advancement during swing
Impact on energy expenditure and the mechanics of walking
Six determinants that affect energy expenditure in sustained walking:
pelvic rotation
pelvic tilt
knee flexion in stance phase
foot interaction with the knee
ankle interaction with the knee
lateral pelvic displacement
Moment
Ground reaction forces will creates a “moment” on the joints of the limbs
Moment is what is the “impact on the joint” or ”what does the joint want to do?”
Muscle activation
“What controls the activity of the joint?”
Initial Contact
Initial Contact is part of the “weight acceptance phase” and is 3% of the gait cycle.
It initiates the first rocker of the gait cycle
The progression is then to loading response which is 3% to 12 % of the gait cycle.
Normal GRF are directed anterior to the knee
The body controls these motions with:
Active vastii muscle and tense IT band (via glut max)
Low level activity by hamstring provides protective flexor moment to prevent knee hyperextension
initial contact
ankle is neutral
knee is extended
hip is 30 degrees flexion
what is the GRF
GRF is
posterior to ankle
anterior to knee
anterior to hip
initial contact muscles
gluteals
hamstrings
quadriceps
pre-tibials
During Loading Response:
Frontal Plane
GRF:
Lateral to the ankle
Medial to the knee
Medial to the hip
