wk 4- lesser theories Flashcards
what is STJ axis location and equilibrium model
rotational equilibrium is dependent on the STJ axis location which can change
STJ pronation moment = STJ supination moment
what is a moment
the turning effect produced by forces (muscle, ligaments etc) acting a distance away from an axis (joint)
what are the 2 types of pathological foot types in ROTATIONAL EQUILIBRIUM THEORY
Medially deviated STJ axis = net increase in STJ pronation moments
Laterally deviated STJ axis = net increase in STJ supination moments
what is the average STJ location of axis
42deg inclination from transverse plane
16deg medial deviation from the sagittal plane
what are internal and external generated forces that occur
internal:
-ligamentous and tendon tensile forces
-joint compression forces
extenral:
-GRF
-orthosis and footwear reaction forces
medial deviated STJ axis
the talar neck and head are medial in relation to plantar surface
what does a medial deviated STJ axis look like
- Medial border of the foot will have a convex shape (bulge) viewing from the transverse plane (above)
- Soft tissue contour of the taalar at the ankle will be more medially positioned and internally rotated in relation to calc, viewed from transverse plane
- Increase in convexity in the medial midfoot, from posterior view
if there is an increase in pronation moments = an incresed frequency of what conditions?
Plantar fasciitis
Hallux limitus
2nd mtpj capsulitis
Abductor hallux strain
Sinus tarsi syndrome
PTTD
MTSS
PFPS
Pes anserine bursitis
what modifications can help with a MD STJ axis
-meidal heel skive
-blake inverted device
lateral deviated STJ axis
Less likely than medial
Talar head and neck positioned more laterally in relation to the plantar surface
what does A lateral deviated STJ axis look like
Medial border of the foot has a concave shape
Soft tissue contour more laterally positioned
Increased concavity in the medial midfoot
One or both peroneal tendons bowstrung (pertude through skin)
increased supination moments = increased frequency of what conditions
Lateral ankle sprain
Peroneal tendinopathy
what modifications can you apply to a LD STJ axis
Lateral heel skive
Valgus wedges
GRF occuring medially causes
supination moment, the closer to the axis the GRF occurs, the weaker the moment, the further the stronger
what is the bosjen-moller axes model
low gear to high gear during gait due to windlass mechanism or intriinsic muscles
2 axis,
transverse axis1st met head
oblique axis met heads 2-5
opperating in high gear means
long lever arm=
Plantar aponeurosis tightens during propulsion (windlass mechanism), stiffens foot
Efficient with the long lever, less energy
Transfers weight to contralateral limb
Toe off through 1st met
Less tissue load and pathology
opperating in low gear means
short lever arm
No fascial tightening, less still
Less stable
More overuse of muscles, increased pathology
Lateral toe off
Typically used initially to offload heel (this can be seen on COP line)
what is muscle tuning theory
Muscles vibrate at a certain frequency when you hit the ground, these act as a signal to the CNS to produce a reaction called muscle tuning (done to minimise soft tissue vibrations) for the next contact to pre tune (just before contact) and cause less loads going into tissue, this theory tries to explain why no significant kinematic changes.
what does tuning do for body
Less fatigue
Comfort
How hard muscles/soft tissue have to work
Performance
Less risk of injury
what is foot core theory
Foot function is due to intrinsic foot muscles (barefoot running craze), when weak, everything is unstable and abnormal movement patterns causing overuse injuries occur
what structures are there in foot core theory
passive:bony and articular structures (ligamnts and joint capsules) which maintain arches of the foot
4 arches, medial/lateral longitudinal arch, anterior/posterior metatarsal arches
active:muscles and tendons that attach to the foot
-local stabilisers (plantar intrinsic muscles)
-global movers (extrinsics muscles originating outside the foot but insert in the foot)
neural:sensory recptors in joints, ligaments, muscles and tendons, provide input via stretch responses
how to train foot core
- Exercises for plantar intrinsic muscles (shortening the distance between 1st MPJ and calc) - short foot exercise
- Running barefoot or minimalist shoe training
Improves strength and may increase sensory input
Must build up to wearing minimal or no shoes
what is the arch spring theory
Regulation of energy storage within the foot, elongation of the soft tissues- body absoring energy in the first half of stance phase, recoil-expending energyin second hald of stance phase
Tendons and fascia take this energy, if it goes elsewhere, it could lead to pathology
what is the anatomy trains and biotensegrity
dysfunction or tightness in one area of the fascial train can have an impact on other sections (12 tracks in the body from foot to head)
pain in neck could be linked to the foot due to the fascial linkage or if theres tightness in the front, it could be linked to getting pain in the back
what is the unified theory
Combination of thoeries (Tissue stress, roots, sagittal plane faciliation) to aid orthotic outcomes
1.Reduce abnormal pronatory forces (root)
2.Reduce load through the plantar fascia (TST)
3.Facilitate 1st MPJ function (SPF)
NOTE: not really a thoery more of a concept of using multiple thoeries.
