Architectural & Structural Factors Affecting Strength & Power

Question 1

Architectural/ structures in muscles

Answer 1

Cross sectional area
Pennation angle
fibre length
fibre distribution
type of fibre
innervation ratio

Question 2

limitation to diagram about physiological and mechanical factors in muscle group function

Answer 2

no mention of neural factors

Question 3

What is cross sectional area

Answer 3

Muscle size

Question 4

Pennation angle

Answer 4

how fibres are arranged

Question 5

muscle strength depends on

Answer 5

muscle size

Number of fibres placed parallel to one another

Question 6

What do ACSA and PCSA mean

Answer 6

Physical cross sectional area

anatomical cross sectional area

Question 7

Techniques for measuring changes in CSA

Answer 7

girth
ultrasound
MRI
DEXA scan
CT scan

Question 8

Limitations for measuring changes in CSA

Answer 8

Placement of measurement taken

Question 9

Why doesn’t CSA explain everything

Answer 9

Inability to activate entire muscle

co-activation of antagonist muscles

Limitations with measurement of strength and muscle size

different specific tension

Question 10

CSA definition

Answer 10

how much force can be produced per unit are of muscle fibres

Question 11

Body size

Answer 11

has an effect on force production

larger people are stronger than smaller in general pop

Question 12

Structural factors: Motor unit types key properties

Answer 12

Contractile speed
MU force
Fatiguability

Question 13

Type II motor unit

Answer 13

fast contraction velocity (up to 6 fls)
fatiguable
increased motoneuron size
fibre diameter
iinnervation ratio

Question 14

Type I motor unit

Answer 14

Slow contraction velocity (up to 2 fls)

fatigue resistant

Question 15

Are parallel or in series muscle (architecture) stronger

Answer 15

In parallel due to sum of all three in sequence

Question 16

influence of pennation on thickeness

Answer 16

high pennation = decreased thickness

low pennation = increased thickness

Question 17

why are pennated (fan) muscles better for strength

Answer 17

pack more muscle fibres into set volume of muscle

Question 18

Fibre length

Answer 18

muscle fibres are generally shorter than muscle length

Muscles that tend to have large CSA have short fibres

Question 19

Longer fibre length on ROM and velocity

Answer 19

Greater ROM and velocity contraction

Question 20

fibre length and injury in cruciate ligament reconstruction

Answer 20

Shows shorted fascicles

greater pennation angles

lower eccentric strength

Question 21

measurement of pennation angle and fascicle length

Answer 21

ultrasound
MRI
CT

Question 22

measurement of pennation angle and fascicle length

Answer 22

ultrasound

Question 23

The hamstrings are fusiform muscle group, what are they characterised by

Answer 23

Fast contractions

absolute force of contraction is small compared to pennate muscle groups

Question 24

strength

Answer 24

peak force under a given set of condidtions

Question 25

what happens during isokinetic muscle actions

Answer 25

the peak torque exerted during concentric actions decreases as the angular velocity increases

Question 26

rate of force development is made up of

Answer 26

maximum force

time taken to reach given % force

Question 27

Does muscle tendon stiffness influence RFD

Answer 27

tissue stiffness is inversely proportional to length, longer muscles and tendons are more compliant and force transmission may be slower