732 Gait, COM, Kinetics, Aging, etc.

total vertical displacement of COM during gait

5cm

when is COM highest in vertical displacement with gait

midpoint of single limb support

when is COM lowest in vertical displacement with gait

midpoint of the double limb support

maximum side to side displacement

midpoint of the stance phase on the supporting limb

total motion of side to side displacement

4cm (2cm to right and 2cm to left)

in regard to energy- when the supporting limb is in front of body

the body slows down which decreases kinetic energy and increases potential energy

in regard to energy- when the supporting limb is behind the body

the body speeds up increasing kinetic energy and decreasing potential energy

at heel contact, the foot force is anterior and down, the GRF is

posterior and up

at midstance, the foot force is down, the GRF is

up

at toe off, the foot force is down and posterior, the GRF is

up and anterior

peak vertical GRF

120% of body weight

when are the two peaks in vertical GRFs

heel contact and push off

peak anterior-posterior GRF

20% bodyweight

when are peak posterior forces

foot flat

when are peak anterior forces

push off

path of center pressure

the continuous trajectory representing the average location of all downward forces applied to the ground by the foot

aging is associated with

• decreased strength

• decreased ROM

• increased balance impairments

parameters in gait that are decreased with age

• speed

• stride length

• step length

• joint excursion

• ankle power during push off

• functional base of support

parameters in gait that are increased with age

• double support

• toe out

• step width

diminished of gait speed is associated with

• decreased stride length

• decreased single support time

• increased double support time

muscle activity with age

higher torque parameters of hip flexion and adduction, knee extension, and ankle dorsiflexion and inversion. Fall risk elders may also use co-contraction to increase stability

antalgic gait

an abnormal gait pattern caused by pain

details of an antalgic gait pattern

• characterized by weight avoidance on painful limb (except hip pain cases)

• shorter step length and stance time on painful side

• shorter swing time on the uninvolved side

central nervous system disorders

primary cause of gait impairments; the inability to generate and/or control an appropriate level of muscles leads to impaired motor control

central nervous system disorders impaired motor control examples in gait

• over-reaction to stretch

• impaired selective control, with reversion to primitive locomotor responses

• abnormal muscle timing can affect the cyclic nature of gait

• spasticity

musculoskeletal impairments

abnormal ROM, muscle weakness, and/or sensory loss can affect gait

MSK impairments can be secondary to other conditions such as

• muscle weakness due to nerve damage

• increased joint laxity secondary to previous ankle sprain

• abnormal ROM at one joint can lead to compensatory changes in joint movement at surrounding joints