what is the creation of power for efficient forward motion?
- pull placed on the swing limb is the most powerful source that acts on the body’s centre of mass
- momentum provides continuation of motion
- gravity permits the body to use its own mass, by acting on the trunk when it is placed just in front of the planted foot
- elastic tissue response represents a complex form of energy return. energy that is stored at impact is returned
what are the premises of the sagittal plane theory?
premises
- the foot must be able to resist forces that are applied to it
- this must coordinate with the power input which is required to move the body forward over the foot
- the foot has 3 autosupportive mechanisms
What are the auto supportive mechanisms?
- Calcaneocuboid locking
- the locking wedge and truss effect
- the windlass effect
Explain high gear vs low gear theory?
- larger thrust is gained through high gear propulsion where medial slip of plantar aponeurosis is seen during gait. Its believed this is the windlass.
- low gear propulsion is less effective and requires more muscular involvement
what can cause a Sagittal plane block?
- first ray 1st MPJ motion impeded
- talus adduction, adduction RF on FF therefore TP force greater than SP force
What is function and structural hallux limitus?
hallux limitus
-no efficient 1st ray dorsiflexion
Functional
-reduced or inadequate 1 MPJ motion during gait while maintain adequate ROM of during non weight bearing examination
Structural
- primary and secondary deformities such as OA
- non weightbearing and weightbearing
List and describe the compensation mechanism for sagittal plane blockage?
Altered heel lift
- no Df of 1st MPJ, Df occurs somewhere else
- flexible foot compensation through MTJ, collapse and Df occurs
Vertical toe off
- apropulsive gait, foot lifted off the ground before propulsion
- slow movement low energy efficient
inverted step
- occurs when weight fails to move medially
- due to no calcaneocuboid locking, forefoot valgus
- excessive wearing of lateral shoe
Abducted and adducted toe off
-abductory twist occurs if the body can no longer move forward to compensate
compensation
Flexion compensation of the body
- if the body cannot come over efficiently abnormal torso flexion occurs
- straightened spine and HS, flexed head and neck overtime leads to chronic postural change
Explain the calcaneobuboid locking?
- Dependent of tension of plantar fascia
- During heel lift plantar fascia tightens which enables locking of calcaneocuboid
- thus allowing shift of weight from lateral to medial
Explain the two metatarsal head axes system?
- during heel lift foot must move from OA 2-5 to TA 1-2 to efficiently move over the foot
explain the locking wedge and truss effect?
- describes foot moving from midstance where metatarsals are parallel to the ground to being perpendicular
- fulcrum effect, met being perpendicular to surface more effectively the foot can transfer weight
- increase rearward thrust and forward momentum
Explain the windlass mechanism?
- DF of hallux at heel lift, tightens plantar fascia
- plantar fascia pulls hallux into metatarsals
- there is then a equal opposite force to further DF the hallux
- A Pf moment is created by the medial cuneiform force acting on base of met
-overall Pf moment from windlass over powers Df moment created
