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Flashcards in Locomotor biomechanics Deck (11)
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1

List common lameness indications

- many described
- most commonly: walk/trot
* torso movement (head nod and hip/pelvic hike)
- limb movement (fetlock joint angle = relates to force, foot placement = crossing under body, swing phase movement = toe drag, step length, cranial/caudal phase)

2

Outline head nod in relation to lameness

- drops on non-lame diagonal
- less excursion on lame diagonal
- accelerated upward on non-lame diagonal
- Force = movement * acceleration
- higher acceleration --> higher force

3

Describe 'hip hike'

hip on the lame side has a greater vertical displacement and appear to drop before hiking up to the original position

4

Outline the mechanism for hip hike

- DURING LAME LIMB STANCE: small amount of force --> reduced fetlock hyperextension, small amount of rotation, reduced pushoff. Reduced pelvic movement.
- DURING SOUND LIMB STANCE: increased force --> more fetlock hyperextension, more rotation, increased pushoff. Increased pelvic movement more obvious on lame side
* overall pelvic rotation amplifies effect at level of tuber coxae
* same mechanism for TL lameness: increased force with sound limb, increased movement during sound limb stance, more obviously visible on contralateral side

5

What is the most sensitive parameter for change in hip hike after blocking (nerve)?

HHD = hip hike difference

6

Outline the mechanics of force on a circle

- inwardly directed force provides centripetal acceleration
- result is alingment of limbs with GRF

7

What is joint torque?

- GRF creates joint moments
-to provide stable support, the GRF moments need to be counteracted by internal forces (mm/ tendon forces)
- increased movement arm --> increased internal force
- increased tendon force --> increased stress/strain --> increased risk of injury

8

What 3 factors may influence the inside/outside force?

- weight support
- stride length
- lean angle

9

What dictates amount of vertical force?

gravity (vertical force is produced when the limb is in contact with the ground)

10

Describe vertical force in different stride lengths

- shorter stance/ longer swing --> higher force
- longer stride --> longer swing phase --> higher phose
- outside limb needs to produce higher force

11

Why is the lame limb often seen easiet on inside of circle/ lungeing?

lower force but more acute angle on inside of circle