Biomechanical principles & gait

Question 1

What does Wolff’s law state?

Answer 1

That a bones shape and structure is a reflection of its mechanical loading history eg a tennis players racket are will have greater bone density than the other arm.

Question 2

What does Wolff’s law state?

Answer 2

That the shape and structure of a bone is a reflection of its mechanical loading history.

Question 3

What six different mechanical forces can bone be subjected to?

Answer 3

Unloaded, tension, compression, shear, bending and torsion.

Question 4

Vertebral fractures are commonly a result of which force being applied to the bones?

Answer 4

Compression.

Question 5

Pulled muscles and avulsion fractures are commonly a result of what type of force being applied to bones?

Answer 5

Tensile forces.

Question 6

A common ACL/MCL injury sustained by american football players is caused by which force acting on the bones?

Answer 6

Shear Force (planted/strapped foot and opposing tackle).

Question 7

Which two bones are frequently subjected to bending forces, especially when skiing?

Answer 7

Fibula, Tibia and femur.

Question 8

What makes up the menisci?

Answer 8

Fibrocartilagenous tissue.

Question 9

What operation can cause an increase in the incidence of OA in the knee?

Answer 9

Meniscectomy

Question 10

By what % does a menisci increase congruency in the knee joint?

Answer 10

50%.

Question 11

Tendons connect what to what?

Answer 11

Muscle to bone.

Question 12

Ligaments connect what to what?

Answer 12

Bone to bone.

Question 13

What type of collagen to tendons contain?

Answer 13

Type 1 collagen.

Question 14

What structure resists tensile forces and stores up energy in order to act as a spring during locomotion, complementing muscle force?

Answer 14

Tendons.

Question 15

What are the main functions of ligaments?

Answer 15

To guide and limit joint mobility and to maintain congruence and act as strain sensors.

Question 16

Why do strained ligaments hurt?

Answer 16

They have a good nerve supply - complete rupture results in no pain - surgery needed.

Question 17

What are the four major properties of skeletal muscle?

Answer 17

Irritability - responds to nervous stimulation
Contractibility
Extensibility
Elasticity

Question 18

Which globular protein is involved in muscle contraction?

Answer 18

Troponin (and tropomyosin in the thin filaments).

Question 19

Plyometrics refers to what type of action?

Answer 19

Repeated and rapid muscle stretches and contractions, ie jumping up and down.

Question 20

An agonist muscle is defined as…

Answer 20

the muscle responsible for producing the movement.

Question 21

An antagonist muscle is defined as…

Answer 21

the muscle that opposes the agonist in a particular movement ie relaxes to allow an agonist to act, or contracts proportionally to produce a slow movement.

Question 22

A Fixator or stabiliser muscles is defined as…

Answer 22

a muscle which provides an immobile base for a join on which other prime movers act.

Question 23

A synergist muscle is defined as…

Answer 23

a muscle that prevents unwanted movements which would be produced if the prime movers (agonist) acted alone.

Question 24

What types of mechanical forces can bones be put under?

Answer 24

Unloaded, tension, compression, shear, bending and torsion.

Question 25

What are the three muscle mechanism components?

Answer 25

Swing
Shunt
Spin

Question 26

What is passive insufficiency?

Answer 26

A factor limiting biarticular muscles that span two joints, i.e. hamstring. Don’t allow movement at both joints at the same time.

Question 27

What is active insufficiency?

Answer 27

A factor limiting movement due to a muscles inability to contract by more than a fixed amount. There’s insufficient ‘shortening’ ability when another joint is already flexed.

Question 28

What defines the concurrent movement of muscles?

Answer 28

When two muscles are acting together, shortening at one end, but lengthening at the other.

Question 29

What defines COUNTERcurrent movement of muscles?

Answer 29

The opposite of concurrent movement, where the muscles involved either lengthen at both ends or shorten at both ends.

Question 30

What is gait?

Answer 30

The movement pattern associated with human locomotion - running and walking.

Question 31

The gait cycle is defined as the interval between…

Answer 31

Two successive heel strikes of the same foot.

Question 32

Stance phase and swing phase make up what?

Answer 32

The Gait Cycle.

Question 33

What is the stance phase defined as?

Answer 33

Heel strike to toe off.

Question 34

What is the swing phase defined as?

Answer 34

Foot is off the group and is moving away from toe-off to the heel strike - the weight baring phase.

Question 35

Over pronation of the foot can be caused by, and can result in what conditions.

Answer 35

Subtular joint hypermobility, collapsed medial longitudinal arch. Causes increased susceptibility to achilles tendon problems and hallux valgus.

Question 36

What is hallux valgus?

Answer 36

A bunion.

Question 37

What characterises a hemiplegic gait?

Answer 37

One leg swung out laterally.

Question 38

What pathology is a common cause of a hemiplegic gait?

Answer 38

Stroke

Question 39

A parkensonian gait can also be described like?

Answer 39

A shuffle - small, tentative steps with little peripheral movement, do not have a natural arm swing.

Question 40

An antalgic gait is used to describe what type of walk?

Answer 40

A limp/movement away from the side of pain.

Question 41

What is an ataxic gait caused by?

Answer 41

Cerebellar dysfunction.

Question 42

Tipping of the pelvis during the stance phase of the gait cycle is suggestive of which pathology?

Answer 42

Trendelenburg.