Exam Studying

Question 1

A MUSCLE CONTAINS AN EQUAL NUMBER OF FAST-TWITCH AND SLOW-TWITCH MUSCLE FIBERS. THIS MUSCLE WILL HAVE MORE OF WHICH TYPE OF MU?
a) type I
b) type IIa
c) type IIb

Answer 1

a) type I

Question 2

THREE MUSCLES HAVE THE SAME CROSS-SECTIONAL AREA AND THE FOLLOWING FEATURES
-MUSCLE A: 5000 MU, MOSTLY TYPE I
-MUSCLE B: 400 MU MOSTLY TYPE I
-MUSCLE C: 400 MU MOSTLY TYPE II
WHICH MUSCLE HAS THE BEST FINE MOTOR CONTROL?
a) Muscle A
b) Muscle B
c) Muscle C

Answer 2

a) muscle B

Question 3

THE MOST ATP PER SECOND CAN BY PRODUCED BY WHAT METABOLIC PROCESS
a) PCr
b) Glycolysis
c) Oxidative Phosphorylation
d) Lactate dehydrogenation

Answer 3

a) PCr

Question 4

WHICH TYPE OF MU WOULD AN ATHLETE USE WHEN TESTING THEIR 1 REP MAX BENCH PRESS
a) Type I
b) type IIa
c) type IIx
d) all of the above

Answer 4

d) all of the above
-size principle
-recruit in order

Question 5

WHICH OF THE FOLLOWING IS TRUE?
a) Type IIx MU fire at a slower max rate than type II MU
b) Type I MU produce peak force before type II MU
c) Activating 50% of you MU requires you to use about 50% of your maximal effort
d) Type I MU are larger than type IIa MU

Answer 5

b) Type I MU produce peak force before type II MU

Question 6

WHICH MODEL OF MU RECRUITMENT OCCURS IN VOLUNTARY CONTRACTION?
a) After-hyperpolarization
b) Onion-skin model
c) avengers assemble model
d) Science is a spectrum - we don’t know for sure they are both theories

Answer 6

d) Science is a spectrum - we don’t know for sure they are both theories
-onion-skin model tested through voluntary contractions
-but competing theories for how muscles work in real world
?

Question 7

YOU ARE DOING SHOULDER RAISES WITH EMG MEASURING MOTOR UNIT ACTIVATION IN YOUR DELTOIDS. WHEN WILL YOU HAVE THE LARGEST EMG SIGNAL?
a) when holding the weight at 90 degrees (ISO)
b) Raising the weight (CON)
c) Lowering the weight (ECC)
d) holding the weight at 90 degrees (ECC)

Answer 7

b) Raising the weight (CON)

Question 8

WHAT IS NOT A PROPERTY OF TYPE I FIBERS?
a) high capillarization
b) high mitochondrial density
c) slow myosin ATPase
d) high storage area for glycogen

Answer 8

d) high storage area for glycogen

Question 9

WHAT FIBER TYPE IS FOUND IN MURINE OR FROG MODELS, BUT NOT HUMANS?
a) Type I
b) Type IIa
c) Type IIb
d) Type IIx

Answer 9

c) Type IIb

Question 10

FROM LARGEST TO SMALLEST, RANK THE CROSS-SECTIONAL AREA OF HUMAN MYOFIBERS:
a) IIx, IIa, I
b) l, lla, llx
c) lla, llx, I
d) IIb, IIa, I

Answer 10

c) lla, llx, I

Question 11

WHAT MOTOR UNIT HAS THE HIGHEST FIBER TO MOTOR UNIT RATIO?
a) IIx
b) IIa
c) I
d) Ia

Answer 11

a) IIx

Question 12

WHAT IS NOT A BENEFIT OF HAVING THE FIBERS OF ONE MOTOR UNIT SPREAD ACROSS THE ENTRIE MUSCLE?
a) neighboring fibers can share blood supply
b) unequal pull on tendon, allowing greater force
c) distribution allows for smoother contraction
d) metabolic buildup is reduced

Answer 12

b) unequal pull on tendon, allowing greater force

Question 13

WHAT FIBER TYPE WOULD HAVE THE LARGEST REFRACTORY PERIOD
a) slow oxidative fibers
b) fast oxidative glycolytic fibers
c) fast glycolytic

Answer 13

a) slow oxidative fibers

Question 14

THE MUSCLE BIOPSY BETWEEN AN OLYMPIC SPRINTER AND AN OLYMPIC MARATHONER ARE COMPARED. THE AMOUNT OF PROTEINS DECTECTED THAT ARE ASSOCIATED WITH CALCIUM PUMP MACHINERY WOULD BE:
a) higher in the sprinter
b) higher in the marathoner
c) no difference between athletes

Answer 14

a) higher in the sprinter

Question 15

ALWAYS A SCIENTIST, DR.NEDERVEEN FIRST JUMPS OFF OF HIS CHAIR AND THEN JUMPS OUT OF THE 1ST FLOOR OF IWC TO TEST HIS GTO RESPONSE. HE NOTICES THAT THE GTO RESPONSE;
a) is less active during the faster lengthening velocities
b) is more active during faster lengthening velocities
c)the GTO is a reflex, there is no difference between velocities

Answer 15

b) is more active during faster lengthening velocities

Question 16

THE MUSCLE FIBERS OF ONE MU;
a) are clustered together tightly in the same area of a muscle
b) are recruited by order of size (small to large)
c) contain the same myosin heavy chain isoforms
d) are innervated by multiple motoneurons

Answer 16

c) contain the same myosin heavy chain isoforms

Question 17

WHICH OF THE FOLLOWING STATEMENTS IS NOT TRUE?
a) In a muscle with an even type I : type II ratio, there are more type I motor units
b) Muscle fibers from type I MU have a faster rate of force relaxation than those for type II MU
c) Regardless of training status, Type II MU have greater specific force than type I MU
d) Muscle fibers from type II MU have the same density of myofilaments than those from type I MU

Answer 17

b) Muscle fibers from type I MU have a faster rate of force relaxation than those for type II MU

Question 18

IN COMPARISON TO SLOW TWITCH MUSCLE FIBERS, THE FAST TWITCH FIBERS HAVE;
a) greater absolute force
b) lower recruitment threshold
c) greater myofibrillar density
d) all of the above

Answer 18

a) greater absolute force

Question 19

WHY IS THERE A GREATER SPECIFIC FORCE IN A TYPE II VS TYPE I MOTOR UNITS?
a) there are more active cross-bridges during
b) there are more muscle fibers activated
c) there are more myofilaments to produce force
d) all of the above

Answer 19

d) all of the above

Question 20

SOMEONE WITH A HIGH PERCENTAGE OF SLOW TWITCH FIBERS WILL;
a) have a power velocity curve shift
b) have a lower Vmax
c) achieve peak power at a lower velocity
d) all of the above

Answer 20

d) all of the above

Question 21

WHICH OF THE FOLLOWING STATEMENTS IS CORRECT?
a) muscle fibers conduct action potentials much slower than motor nerve axons because they don’t have myelin
b) type I muscle fibers have a slower conduction velocity than type IIx because of a greater t-tubular network
c) larger diameter axons have greater t-tubular network
d) the faster conduction velocity of type IIx motor nerves is due to the smaller diameter of their axons

Answer 21

a) muscle fibers conduct action potentials much slower than motor nerve axons because they don’t have myelin

Question 22

IN COMPARING THE FORCE-FREQUENCY RELATIONSHIP BETWEEN TYPE IIx AND TYPE I MU, IT IS TRUE THAT;
a) type I units will have a lower maximal force
b) neither type of unit will achieve full force summation at the firing frequency they are first recruited at
c) maximum force will be achieved at lower firing frequencies in type I units
d) all the above

Answer 22

d) all the above

Question 23

THE FIRING RATE REQUIRED FOR SUMMATION OF A TYPE IIx MU WILL BE FASTER THAN TYPE I UNIT BECAUSE;
a)the sarcoplasmic reticulum is larger and more extensive in the type IIx muscle fibers
b) the diameter of the axon of a type IIx motor unit is greater
c)the size of the motoneuron soma is greater in the type IIx unit
d) the twitches are faster in the type IIx MU

Answer 23

c)the size of the motoneuron soma is greater in the type IIx unit

Question 24

DURING 10 REPS OF BICEP CURLS OF A 20KG DUMBBELL, THE QUANTITY OF BICEP EMG WILL BE;
a) lowest during the last contraction
b) lowest during the lifting phase
c) lowest during the lowering phase
d) equal for the lifting and lowering phase

Answer 24

c) lowest during the lowering phase

Question 25

IN REGARD TO MU ACTIVATION, IT IS TRUE THAT;
a) MU recruitment is the predominant gradation mechanism between 50 and 100% maximum muscle force
b) for the same absolute force and velocity, the amount of motor unit activation would be the same in ECC and CON contractions
c) Type IIx MU would be recruited in both slow and fast maximal CON contractions on an isokinetic dynamometer
d) all of the above

Answer 25

c) Type IIx MU would be recruited in both slow and fast maximal CON contractions on an isokinetic dynamometer