Kines 3 - OGA
Terms in this set (171)
The moment when the foot contacts the ground
Weight is rapidly transferred onto the outstretched limb, the first period of double-limb support
Shock absorbed - foot-flat position achieved
The body progresses over a single, stable limb; CL swing limb provides momentum
Progression over stance limb continues; body moves ahead of the limb and weight is transferred onto the forefoot
A rapid unloading of the limb occurs as weight is transferred to the CL limb; second period of double limb support; forefoot remains on floor for balance assist; knee rapidly flexes while weight is shifted to CL imb
The thigh begins to advance as the foot comes up off the floor; knee continues to flex
The thigh continues to advance as the knee begins to extend; the foot clearance of the ground maintained
The knee extends; the limb prepares to contact the ground for IC; leg reaches out to achieve step length
Weight acceptance phase
Includes IC and LR; period when weight is rapidly loaded onto outstretched limb; impact of floor-reaction force is absorbed and the body continues in a forward path while stability is maintained; both feet are in contact with the ground
Single limb support
Includes MSt and TSt; period when body progresses over a single, stable limb; weight is transferred onto MT heads and heel comes off ground
Swing limb advancement
Includes PSw, ISw, MSw, TSw; period when limb is unloaded and foot comes off ground; limb is moved from behind body to in front of body, reaching out to take the next step
ROM of ankle at IC
What type of torque demand is present when ankle is in IC?
PF torque - posterior to ankle joint
Which muscles maintain the ankle's foot position for LR?
Pretibial - tibialis anterior and long toe extensors
What is the functional significance of the ankle at IC?
Positioned for heel rocker
What is the purpose of the heel rocker?
Forward progression of tibia and shock absorption
ROM of ankle at LR
What is the torque demand of ankle at LR?
Which muscles are active at ankle LR?
Pretibial muscles eccentrically
Which muscle's activity peaks in LR for ankle?
Which muscles become active late in LR to control tibial advancement?
What is the functional significance of the ankle at LR?
Heel rocker created; pretibial muscles pull tibia forward creating forward momentum and initiating knee flexion
ROM of ankle at MSt
Ankle DF to 5
What is the torque demand of the ankle at MSt?
What muscles are active at the ankle in MSt and why?
Gastroc/soleus to control forward progression of the tibia
What is the functional significance of the ankle at MSt?
Calf muscles create knee stability by controlling tibial advancement; body is able to progress forward over a stable foot and tibia
What is the ankle rocker?
Ankle at MSt; forward momentum maintained while ankle moves into 5 DF
ROM of ankle at TSt
10 DF; 30 MTP ext
When does DF torque reach its peak?
What does the DF torque in TSt create?
The greatest muscle demand at any joint during gait cycle - gastroc/soleus
What do the gastroc/soleus prevent at TSt of ankle?
Forward tibial collapse
What do the gastroc/soleus allow at TSt of ankle?
Heel to rise
What is the forefoot rocker and when does it occur?
The calf muscles allow maximal forward progression by controlling ankle DF and allowing heel to rise - contributes to CL step length; created by MTP extension
What is the primary function of the "rockers"?
Preserve forward momentum
What is the significance of knee flexion?
Shock absorption and tibial progression
ROM of ankle at PSw
15 PF; 60 MTP ext
What happens to the torque demand at ankle in PSw?
DF torque rapidly decreases
What muscle activity stops in PSw at ankle?
What muscle activity contributes to ankle moving into PF at PSw?
Residual PF activity but mainly PASSIVE TENSION of gastroc/soleus
What muscle activity is initiated in preparation for DF ankle at end/after PSw?
In which stages does the forefoot remain on the floor and why?
Ankle PSw - to provide balance assist
At which stage does the most PF occur in gait?
ROM of ankle at ISw
What torque demand is present at ankle in ISw?
Low level PF torque
What muscles initiate DF in ISw?
Which muscles peak in activity in ISw of ankle?
Extensor hallucis longus and extensor digitorum longus
What is the functional significance of ISw of ankle?
DF needed to clear foot of ground - but neutral not yet achieved
ROM of ankle at MSw
DF to neutral
What torque demand is present at ankle in MSw?
Low level PF torque
What muscles are active in MSw at ankle?
What is the functional significance of ankle at MSw?
Foot clears the ground by 1 cm
ROM of ankle at TSw
What is the torque demand of ankle in TSw?
Low level PF torque diminishes to zero
What muscles are active at ankle in TSw and why?
Pretibial muscles - to prepare leg for LC so no foot slap/drop occurs - TA turns on to pull tibia forward and create knee flexion
What is the functional significance of ankle at TSw?
Neutral position assures a heel contact for IC
ROM of STJ in Weight Acceptance phase
LR: calcaneus 5 everted; STJ moves into pronation
TD at STJ in Weight Acceptance phase
Eversion due to calcaneus being lateral to WB axis of tibia
MA of STJ in Weight Acceptance phase
TA and TP = eccentrically
TA stops after maximal pronation; TP continues into SLS
FS of STJ in Weight Acceptance phase
Pronation to assist in shock absorption = IR of tibia; unlocks MTJ for shock absorption of forefoot floor contact
What reduces rotary stress on ankle joint in Weight Acceptance phase?
Pronation of STJ
ROM of STJ in Single Limb Support (SLS)
Eversion position remains relatively unchanged from position achieved in Weight Acceptance
Late TSt: progressive reduction of eversion to about 2 (from 5) by end of SLS phase
TD of STJ in SLS
Eversion torque diminishes in MSt
Inversion torque created in TSt as heel rises due to BW progressing onto obliquely aligned MT heads and pull of soleus
MA of STJ in SLS
TP, soleus, peroneals active
FS of STJ in SLS
TP and soleus eccentrically control eversion then concentrically move STJ to inversion
What does the reduction in calcaneal eversion at STJ in SLS cause?
Increased stability of MTJ - creating rigid forefoot lever during TSt - promoting forefoot rocker
Which muscles provides lateral stability of STJ and foot in SLS?
Peroneus (fibularis) longus and brevis
ROM of STJ in Swing Limb Advancement phase (SLA)
TD of STJ in SLA
Inversion torque diminishes to zero
MA of STJ in SLA
FS of STJ in SLA
Foot clears ground; ankle and STJ positioned for heel contact
ROM of knee in IC
TD of knee in IC
Brief extension torque
MA of knee in IC
Quads contract in preparation for LR - creating flexion torque; hams contract to counteract brief extension torque
FS of knee in IC
Extension torque stabilizes knee at IC
ROM of knee in LR
TD of knee in LR
Rapid, moderate intensity flexion torque
What is the greatest shock absorption mechanism in gait?
Knee flexion in LR
What causes the TD of knee in LR?
Heel rocker and position of body behind foot
MA of knee in LR
What muscle's activity peaks and what muscle's activity diminishes in LR of knee?
FS of knee in LR
Shock absorption and limb stability maintained while forward progression continues
ROM of knee in MSt
TD of knee in MSt - what creates it?
Extension torque - created by forward momentum of CL swing limb
What is the significance of the extension torque of knee at MSt?
Allows quads to stop contracting
MA of knee in MSt
Quads stabilize until knee extension torque begins - knee indirectly stabilized by calf muscle restraining tibia
FS of knee in MSt
Knee stability maintained via knee extension torque and calf muscle activity
ROM of knee in TSt
Knee appears unchanged from MSt - 5 flex
TD of knee in TSt
Extension torque peaks and diminishes
MA of knee in TSt
No knee extensor muscles active - restraint of tibia by gastroc/soleus (also stabilizes knee); biceps femoris active in some people to prevent knee hyperextension
FS of knee in TSt
Joint stability maintained as forward progression continues
T/F: The knee never reaches 0 in the gait cycle.
ROM of knee in PSw
TD of knee in PSw
Rapid unloading by transfer of BW to other foot allows residual PF at ankle to generate flexion torque at knee
MA of knee in PSw
Minimal knee flexor activity from gracilis - mostly passive tension
FS of knee in PSw
Motion in this phase is more than half of the knee flexion required in swing - with NO direct muscle activity; foot is still in contact with floor
ROM of knee in ISw
TD of knee in ISw
Thigh advancement by active hip flexion along with tibia inertia = knee flexion torque
MA of knee in ISw
BF short head, sartorius and gracilis activity peak; active concentric hamstrings contribute about 20 flex
FS of knee in ISw
Foot clears ground and thigh begins to advance
ROM of knee in MSw
When does the tibia achieve a vertical position?
TD of knee in MSw
Transition to knee extension torque in late MSw due to tibial momentum - assists with knee extension
What is the significance of hamstrings in MSw (knee)?
Slow the swing - eccentrically contracting
MA of knee in MSw
Knee extension created by momentum and gravity - SH of biceps femoris may control rate of knee extension; hams may be more active late in MSw
Where are the hamstrings most active?
MSw of knee to TSw of knee
FS of knee in MSw
Knee extension necessary for step length begins in this phase
ROM of knee in TSw
TD of knee in TSw
Knee extension torque, created by rapidly advancing tibia, continues
MA of knee in TSw
Quads concentrically to ensure full knee extension; hamstrings peak to decelerate thigh
FS of knee in TSw
Step length optimized by leg reaching out
ROM of hip & pelvis in IC
20 thigh flex; 5 forward rotation
TD of hip & pelvis in IC
Rapid, high intensity flexion torque begins
MA of hip & pelvis in IC
ALL hip extensors are active - primarily gluteus maximus and adductor magnus
Why are all hip extensors active in IC for hip & pelvis?
To prepare to stabilize thigh during LR
Which muscle's actions are reduced in IC for hip & pelvis?
Semimembranosus and biceps femoris long head
FS of hip & pelvis in IC
Hip & pelvis are in a position of forward reach
ROM of hip & pelvis in LR
20 flex and 5 forward rotation
TD of hip & pelvis in LR
Rapid, high intensity flexion torque present
What is the second highest torque demand during the gait cycle?
Flexion torque in LR of hip & pelvis
What is the highest torque demand during the gait cycle?
What TD begins in LR of hip & pelvis?
MA of hip & pelvis in LR
Lower fibers of glut max, adductor magnus and hams - to counteract flexion torque
Which muscles peak in activity in LR of hip & pelvis?
Posterior TFL, glut med/min, upper glut max
What is the function of the muscles that peak in LR of hip & pelvis?
Stabilization of pelvis in frontal plane
FS of hip & pelvis in LR
Hip joint stabilized during shock absorption; trunk flexion prevented and thigh stabilized; pelvis stability in frontal plane
ROM of hip & pelvis in MSt
Neutral for both
TD of hip & pelvis in MSt
CL swing limb moves body past stance limb leading to change from flexion to extension torque by end of MSt; adduction torque continues
MA of hip & pelvis in MSt
No hip muscle activity required in sagittal plane; pelvis stabilized in frontal plane by abductor group
FS of hip & pelvis in MSt
Stable joint position achieved in sagittal plane without hip extensor muscle activity; pelvis stabilized to prevent drop in frontal plane
ROM of hip & pelvis in TSt
20 apparent hyperextension and 5 backward rotation (and anterior pelvic tilt)
TD of hip & pelvis in TSt
Hip extension torque for stabilization; adduction torque diminishes
MA of hip & pelvis in TSt
Posterior TFL stops; anterior TFL activates to restrain hyperextension of hip
FS of hip & pelvis in TSt
Step length maximized; pelvic rotation makes gait pattern look smooth
ROM of hip & pelvis in PSw
Thigh falls forward to 10 apparent hyperextension (due to simultaneous 40 knee flex); pelvis 5 backward rotation
TD of hip & pelvis in PSw
Hip extension torque diminishes as limb is unloaded
MA of hip & pelvis in PSw
Adductor longus activity contributes to femur flexion; RF active in some
FS of hip & pelvis in PSw
Limb advancement begins - hip flexion motion contributes to knee flexion
ROM of hip & pelvis in ISw
15 thigh flex and 5 backward rotation
TD of hip & pelvis in ISw
Tibial inertia maintains hip extension torque initially - hip extension torque approaches 0 by end of this stage
MA of hip & pelvis in ISw
Iliacus, gracilis, sartorius, adductor longus
Which muscles peak in activity in ISw for hip & pelvis?
Iliacus, gracilis, sartorius
FS of hip & pelvis in ISw
Limb advancement continues
ROM of hip & pelvis in MSw
25 flex (same as knee); pelvis neutral
TD of hip & pelvis in MSw
Gradually increasing hip flexion torque due to limb inertia
MA of hip & pelvis in MSw
Hamstrings initiate activity in late MSw
Why do hamstrings initiate activity late in MSw for hip & pelvis?
To slow swinging limb
FS of hip & pelvis in MSw
Thigh advancement slows; momentum created by swinging limb helps carry body past CL stance limb
ROM of hip & pelvis in TSw
20 flex and 5 forward rotation
TD of hip & pelvis in TSw
Hip flexion torque diminishes by end
MA of hip & pelvis in TSw
Hamstrings, adductor magnus, lower glut max, TFL, glut med, upper glut max
What muscles peak in their activity during TSw of hip & pelvis?
What is the function of the adductor magnus and lower glut max fibers during TSw of hip & pelvis?
Initiate activity in preparation for stabilization of hip in sagittal plane during weight acceptance that is approaching
What is the function of the TFL, glut med, upper glut max during TSw of hip and pelvis?
Prepare for stabilization of pelvis in frontal plane during weight acceptance that is approaching
FS of hip & pelvis in TSw
Forward rotation of pelvis contributes to step length; limb is positioned for heel first IC
Trunk action during gait cycle
What causes arm swing in gait?
Trunk rotation of about 5 in horizontal plane
Is arm swing passive or active?
When does arm swing occur?
When walking fast enough - about 90 steps per minute
What are the accomplishments of Weight Acceptance?
Forward progression, stability, shock absorption
What is the critical event of IC?
Heel first contact
What is the critical event of LR?
Hip stability; controlled knee flexion and ankle PF
What are the accomplishments of SLS?
Stability (on one leg) and forward progression
What is the critical event of MSt?
Controlled tibial advancement
What is the critical event of TSt?
Controlled ankle DF with heel rise; trailing limb generates momentum for CL limb
What can substitute for direct muscle activity?
What are the accomplishments of SLA?
Foot clearance of 1 cm and limb advancement
What is the critical event of PSw?
Passive knee flexion to 40 and ankle PF
What is the critical event of ISw?
Hip flexion to 15 and knee flexion to 60
What must occur in order for foot clearance?
Knee flexion to 60
What is the critical event of MSw?
Further hip flexion to 25 and ankle DF to 0
What is the critical event of TSw?
Knee extension to neutral (possible 5 flex)