KIN 4571 - human locomotion

what changes when quadrapeds switched to bipeds/

anatomical changes preceded neurological changes; foramen moved forward (directed the neural changes); limb and muscle coordination changed; new posture and equilibrium demands

what are the events of the gait cycle?

right heel contact (RHC), left heel contact (LHC), right toe off (RTO), and left toe off (LTO)

true or false: humans spend most of the time on single support compared to double support when walking

true

what is the swing phase?

time from toe off to heel contact on one side (consecutive)

what is the stance phase?

time from heel contact to toe off on one side (consecutive)

what is stride length?

distance between heel to heel contact on same foot (consecutive)

what is stride frequency?

number of strides that one makes per unit of time (seconds)

what is step length?

distance between heel contact of one foot and heel contact of the opposite foot

what is step frequency (cadence)?

number of steps that makes per unit of time

what is dorsi-flex?

angle between the shank and foot decreases

what is planter-flex?

angle between the shank and foot increases

true or false: biepdal ambulation is a learned behavior

true

what is the seen differences between infants’ and adults’ gait pattern?

no arm swing → reciprocal arm swing (18~m3y), toe-walking/flatfoot → plantigrade gait (heel-toe)(1.5y), straight leg → accentuated knee bend at early stance (shock-absorption)(3-7y)

what does plantigrade mean?

walking with the entire sole of the foot—including the toes, metatarsals, and heel—flat on the ground

what are the changed from infant to adult gait due to?

anatomy biomechanics, neural differences: segmentally → more dependent on supraspinal system, muscle activation patterns

how do we know there are muscles activation changes?

using an EMG, electromyography

what are the surface electrode signals from of an EMG?

from temporal and spatial summation of all active motor units

what would the EMG of an infant tell us?

high degree of muscle co-contraction, lack of sequential EMG patterns, and synchronous joint movements

what is the role of CNS in locomotion?

generate propulsive forces, modulate changes in center of gravity (CoG), account for muscle properties, adapt to changing conditions in the environment, coordinate multi-limb trajectories based on visual, auditory, vestibular and peripheral afferents

what changes were notable when the subject was asked to walk faster?

stride/step length and stride/step frequency changed

what can occur to increase speed?

both stride/step length and stride/step frequency can increase speed, but one does not need both at the same time to

what are some phase differences between a walk and run?

walking has a longer support phase and shorter swing phase while running has a shorter support phase and longer swing phase

true or false: walking usually has longer double support phase than running

true

true or false: running has more shorter single support phases than walking

true

true or false: stride frequency in running is consistent as velocity increases

true

true or false: stride frequency in walking can increase as velocity increases

true

true or false: stride length in walking and running can increase as velocity increases

true