wk 3- theories

Question 1

what can force cause

Answer 1

motion or deformation of a mass

Question 2

equation for force

Answer 2

F= mass x acceleration

Question 3

force has what, which explains what reaction

Answer 3

equal and opposite reaction, explains ground reaction force

Question 4

define stress

Answer 4

intensity of internal forces within an object or the ability to develop internal resistance to loading force

Question 5

stress equation

Answer 5

S= force / cross sectional area

Question 6

larger cross sectional area for stress means?

Answer 6

it can withstand higher amounts of stress and vice versa

Question 7

define pressure

Answer 7

force applied perpendicular to unit surface area

Question 8

pressure equation

Answer 8

P= force/area

Question 9

higher pressures are caused by

Answer 9

smaller surface areas

Question 10

define strain

Answer 10

relative amount of deformation of an object when it is subjected to load
the change in length

Question 11

strain equation

Answer 11

difference in length

Question 12

what is elastic deformation

Answer 12

initial part of strain when it can bounce back to its original length (reversible)

Question 13

what is plastic defamation

Answer 13

second part of strain when tears occur and the material cannot go back to original length (irreversible)

Question 14

exceeding what will cause rupture in material (plastic defamation)

Answer 14

ultimate tensile strength

Question 15

what are 3 issues with roots theory

Answer 15

1. Reliability of measurement (bisections, ROM, soft tissue movement)
2. Criteria too stringent for normal foot alignment - majority have a deformity
3. Position of STJ during walking

Question 16

what is tissue stress model

Answer 16

injury occurs if the mechanical stresses acting on the tissue is beyond the tolerance of the tissue. Treatment is directed at reducing the load and increasing tissue capacity. Injury is NOT caused by intrinsic deformities.

Question 17

stress on tissues can cause 3 responses

Answer 17

1. Elastic region (reversible, normal give and take)
2. Plastic region (overuse injuries, damages to tissues)
3. Biological response to stress (wolf and davies laws, remodelling due to stresses)

Question 18

types of stresses

Answer 18

1. Axial (compressive-squashed and tensile-lengthened)
   Compressive: bone, plantar foot muscles
   Tensile: tendons, ligaments, muscles
2. Shear (friction)
   Between structures (layers of the skin, joints, uneven muscle fibres, insetion of tendon to bone- attachments arent always perpendicular and often on angles)

Question 19

loading patterns can be

Answer 19

1. Bending- compressive and tensile stresses on opposite sides
   Metatarsals during propulsion
2. Torsion- shear stresses, greatest at the edge
   Jones fractures.

Question 20

what type of stresses does plantar fascia take

Answer 20

compressive (ground)
tensile (conteract pronation)
shear (attachment to calc)

Question 21

4 steps to assessment and managing stress related pathology

Answer 21

1. Identify tissues being excessively stressed

Based on history, symptoms (NILDOCART), what is the patients goal, Come up with initial Dx (skin to bone)

2. Application of controlled stresses

Weight bearing, non weight bearing, palpation, ROM, function/strength assessments
Allows you to develop a working diagnosis and rule out other diagnoses

3. Evaluate findings

Is the cause secondary to mechanical loading?
Assess the structure: what is its action during the activities when it hurts, what stresses are involved, can stresses be elevated, do the tissues have reduced capacity to withstand stress?

4. Institute a management protocol

Reduce stress to a tolerable level (rest, footwear, foot orthoses)
Healing the involved tissue (soft tissue modalities like ice, shock wave, compression)
Restoration of flexibility and strength (increase stress capacity of tissues, exercises)

5. Monitor, evaluate and adjust treatment plan

Question 22

challenges of TSM

Answer 22

1. measurement (no way to measure the tissue stresses, other than compressive stress through plantar pressures)
   We dont know if interventions reduce stress
2. Unclear link between assessment and orthosis prescription (roots theory goes off normal positions, stress model targets reducing stress in areas- more freedom in choosing orthotic prescriptions but more complicated)
3. Doesn’t explain how the foot functions (not useful for prevention)

Question 23

strengths of TS model

Answer 23

1. Outcome measure (treatment guided by symptoms reduction, functional improvement and meeting patient goals) instead of changing their foot to normal like roots theory (kinematic change)
2. Multifaceted approach (foot orthosesis may be part of treatment, not limited to custom made and incorporates other therapies like exercises)

Question 24

what is sagittal plane facilitation of motion theory

Answer 24

3 rockers in the sagittal plane, heel, ankle and 1st MTPJ that facilitate motion (70% of motion). if there is a block in any of these rockers, the body compensates to push through or around it

Question 25

what compensations can be visualised if theres blocks in one of the rockers

Answer 25

-early heel lift (more pressure and load in forefoot) -vertical toe off (more hip dominate in gait) -abducted or adducted toe off (to roll over the foot) -energy into loading the tissue more

Question 26

what are the 3 autosupport mechanisms of SPFM

Answer 26

1. Calcaneocuboid locking- secondary to tightening of the plantar fascia Stabilisation of rearfoot and midfoot with joint locking prior to heel lift 2. Windlass mechanism DF of the hallux pulls on the plantar aponeurosis, shortening the distance between the met heads and calc 3. Closed packing of bone Fascial tightening and locking wedge effect Final piece of stabiliation process and foot can now resist highly repeititve loads

Question 27

what could cause a lack of heel rocker

Answer 27

1. trauma 2. neurological conditions (foot drop)

Question 28

what could cause a lack of ankle rocker

Answer 28

1. ankle equinas (soft tissue or bone) 2. forefoot equinas 3. ankle stiffness

Question 29

what could cause a lack of forefoot rocker

Answer 29

1. hallux ROM decreased 2. functional hallux limitus 3. windlass function

Question 30

compensations/consequences of ankle restriction

Answer 30

Steppage gait (vertical toe off) Early heel lift (bouncy gait) Midfoot pronation Shorter step length Increased genu recurvatum and increased lumbar lordosis (COP forward) Extensor substitution Unstable MTJ

Question 31

compensations/consequences of 1st MTPJ restriction

Answer 31

1. Altered heel lift, a delay in the heel because midfoot pronation occurring to compensate for lack of ROM in MPJ 2. Vertical toe off, foot lifted off the ground (steppage gait) 3. Inverted step, COP deviated laterally to shift the area of toe off 4. Abducted and adducted toe off, a twist 5. Flexion compensation at the torso, knee, head

Question 32

treatment interventions for heel rocker

Answer 32

1. surgery 2. footwear modification (heel rocker sole, heel raises) 3. bracing

Question 33

treatment interventions for ankle rocker

Answer 33

1. stretches 2. manual therapy 3. heel raise 4. surgery

Question 34

treatment for forefoot rocker

Answer 34

1. allow 1st ray plantarflexion (1st ray cut out, mortons reverse extension, cluffy wedge, casting technique) 2. rocker sole

Question 35

what is functional hallux limitus

Answer 35

functional inability of the proximal phalanx to extend on the 1st metatarsal head (DF 20-30deg). Full range of motion non weightbearing.