Normal Mobility Flashcards
what’s a normal locomotion?
bipedal gait in which limbs move in a symmetrical alternating motion
what is velocity?
the average horizontal speed of the body measured over one or more strides
what is stride length?
The distance covered from one heel strike to the next heel strike by the same foot
what is step length
the distance form one foot strike to the foot strike of the other foot
what is cadence
the number of steps per unit of time (steps per minute)
what is normal mean velocity for young, healthy adults?
1.46 m/s
what is normal mean step length?
76.3 cm
what is normal mean cadence
112.5 steps/min
what are the differences between walking and running
- 60/40 distribution of stance/swing switches to 40/60
- double limb support time disappears
- step length and cadence both increase
- initial contact changes
what happens to stance times as velocity decreases
- stance time increases
- double limb support takes up 25% of cycle when cycle duration takes 1.1 sec and 50% when cycle duration takes 2.5 seconds
what happens to swing times as velocity decreases
the total time stays the same
True or false: there is no single correct method for rolling
true
what’s the purpose of momentum transfer strategy?
use for hemiparesis - used for lack of strength
what is the zero momentum strategy
the use for cerebellar pathology (more LE effort)
what is stability
controlling COM relative to moving BOS
what is progression
produces and coordinates rhythmic patterns of muscle activation in the legs, trunk, and arms that successfully move the body in your desired direction
how does stability work in stance phase?
vertical force to support body mass against gravity
how does stability apply to swing phase
repositioning the limb to estimate new BOS
how does progression apply to stance phase
horizontal forces move body in desired direction
how does progression apply to swing phase
advancing swing leg (aka postural control, or pattern of muscle that move you where you want to go)
how does alignment affect balance
- determining the effort required to support the body against gravity
- determining which movement strategies will be effective
- influencing which muscles are recruited and how to recruit them
what is adaptation
strategy used to accomplish progression and postural control (stability) to changing tasks and environmental commands
how does adaptation apply to stance phase
accommodative change in speed and direction
how does adaptation apply to swing phase
avoiding obstacles in path
true or false: adaptation does not require both reactive and anticipatory balance
false: it does require both reactive and anticipatory balance
stance takes up what precent of gait
60%
swing takes up what percent of gait
40%
what is kinematics
the movement of joints and body segments through space
what kinetics
the forces generated ruing the step cycle (join moments)
during stance phase muscle activation what happens to the ANKLE at IC, LR, and mid stance?
- dorsiflexors eccentrically control plantarflexion
- dorsiflexors eccentrically control plantarflexion
- plantar flexors eccentrically control dorsiflexion
during stance phase muscle activation what happens to the KNEE at IC, LR, and mid stance?
- knee extensors concentrically extend the knee briefly
- knee extensors first eccentrically control knee flexion
- no activity during extension moment
during stance phase muscle activation what happens to the HIP at IC, LR, and mid stance?
- hip extensors eccentrically control hip flexion
- hip extensors concentrically extend the hip
- no activity during extension moment
what two theory is happening during terminal stance and what percentage of gait cycle
- active push off theory
- controlled roll off theory
- 31%- 50%
what is active push off theory?
propulsion is generated by plantar flexors; hip and knee extensors control head, arms, trunk during push-off
what is controlled roll off theory ?
forward velocity is generated by roll off (controlled falling) rather than push off
What happens to the ANKLE during terminal stance and pre swing?
- plantar flexors concentrically plantar flex propelling the body forward
- plantar flexors passively recoil
what happens to the KNEE during terminal stance and pre swing?
- no activity to end extensor moment
- rectus femoris (knee extensor) eccentrically decelerates knee flexion
what happens to the HIP during terminal stance and pre swing?
- hip flexors passively resist hip extension
- adductor lung (hip flexor) concentrically initiates hip flexion
what precent of gait cycle is pre swing?
50%-62%
adaptation requires both?
reactive balance and anticipatory balance
muscle réponse patterns are activated from _________ to ________ when balance is threatening during walking
distal to proximal
what two ways are arm movements used to recover balance during gait?
- used to counteract COM displacement
- used in a protective role for school absorption
when is elevating strategy use? and what does it increase?
- used when a trip occurs early in swing phase
- increase hip, knee, and ankle flexion after obstacle contact
when does lower strategy use? what happens?
- when a trip occurs late in swing phase
- early plantarflexion and shortened step length
anticipatory (proactive) balance strategies modify and adapt in two ways?
- prediction
- visually activated strategies
purpose of prediction for anticipatory balance?
used to minimize destabilizing forces as a result of experience
what is the purpose of visually activated strategies?
- used to modify gait in response to environmental threats to stability
- usually carried out within 1 step cycle (may be more if turning)
What happens to stance duration, loading speed, stride length, and heel strike velocity when individuals anticipate walking on a slippery surface? increase or decrease
decrease
what happens to joint motion, muscle cavity and step length when cadence decreases while individuals are walking uphill? increase or decrease
increase
- step length decreases and cadence increases going down hill
what is cognition
the amount of cognitive resources required varies depending on the difficulty of the cognitive task
true or false: young adults reaction times are faster in sitting and slower while standing or walking
true
true or false: reaction times are faster in the single support phase as compared with the double support phase of the step cycle
false: reaction times are slower
dual task performance during obstacle crossing?
- obstacle contact increases when attention is divided
- young adults prioritize gait and obstacle crossing over verbal response time
- cell phone use takes priority over gait stability
importance of somatosensory for sensation
- contribute to appropriate stepping frequency
- joint receptors and muscle spindle afferents contribute to onset of swing phase
- Golgi tendon organ afferents contribute to gait adaptation to changing terrains
- cutaneous information
- changes in reflex amplitude
- interlimb coordination
the importance of vision for sensation?
- visual flow helps us determine our gait velocity
- visual flow helps us align our body with the environment
- peripheral vision controls legs when we are crossing obstacles
- provides topographical information
-provides metric information
the importance of vestibular for sensation
detects angle and momentum of the head
What happens during ascent of stance phase for weight acceptance, pul-up, and forward continuance?
- initiated at middle to front portion of the foot
- facilitated by knee and ankle extensors (vests laterals and soleus)
- ankle generates forward and lift forces (not main source of propulsive force)
what happens during ascent of swing phase for foot clearance and foot placement?
- achieved through tibialis anterior and hamstring activation
- controlled by hip extensors and ankle dorsiflexors
what happens during descent of stance phase for weight acceptance, forward continuance, and controlled lowering?
- absorption of energy at the ankle and knee (eccentric contraction of the gastric/soleus, rectus femurs, and vests laterals)
- eccentric hip extension by hip flexors
- eccentric contraction of the quadriceps and soleus
what happens during descent of swing phase for leg pull through and foot placement?
- early activation of the hip flexors
- by mid swing, hip, knee and ankle extensors prepare for foot placement - tibia’s anterior and gastric activate to ensure contact is made on the lateral border of the foot
what going on with adaptation during descent?
- good visual information about stair height is critical
- with reduced visual input, individuals slow down, increase foot clearance, and place their feet further back on each step to increase safety
