muscular adaptations

Question 1

type I

Answer 1

oxidative capacity = high
glycolytic capacity = low
mitochondrial density = high
capillary density = high
myoglobin content = high
connection time = 80-110
nerve conduction = slow
fatigue rate = low
motor unit force = low
fibres per motor neurone = 10-180

Question 2

type IIa

Answer 2

oxidative capacity = medium
glycolytic capacity = medium
mitochondrial density = medium
capillary density = medium
myoglobin content = medium
connection time = 50
nerve conduction = fast
fatigue rate = fast
motor unit force = high
fibres per motor neurone = 300-800

Question 3

type IIx

Answer 3

oxidative capacity = low
glycolytic capacity = high
mitochondrial density = low
capillary density = low
myoglobin content = low
connection time = 50
nerve conduction = fast
fatigue rate = high
motor unit force = high
fibres per motor neurone = 300-800

Question 4

motor unit

Answer 4

motor neurone and all of the muscle cells it innervates

Question 5

all or nothing law

Answer 5

when a motor neurone fires all of fibres that it innervates contract but the number of neurones firing will differ depending on desired force production

Question 6

sarcomere structure

Answer 6

myofibril has thousands of sarcomeres
joined in series and parallel
function unit of muscles
made of myofilaments

Question 7

myosin

Answer 7

300 per thick filament
globular head
flexible tail
myosin heavy chain isoforms
speed of contraction determined by ATPase

Question 8

capillaries

Answer 8

denser = greater surface area for gas exchange
increased density = improved o2 uptake

Question 9

vascular endothelial growth factor (VEGF)

Answer 9

stimulates angiogenesis
stimulated by low o2

Question 10

angiogenesis

Answer 10

blood vessel formation

Question 11

mitochondria

Answer 11

in cytoplasm
site of ATP production

Question 12

myoglobin

Answer 12

o2 from cell membrane to mitochondria
higher affinity for o2 than Hb
even at low pp allows o2 store

Question 13

change in mitochondria over training endurance

Answer 13

36% increase in size
more type I
convert some type Iix to IIa and I
promotes fast to slow shift

Question 14

endurance training and gene expression

Answer 14

stimulus for altered heavy chain gene expression

Question 15

benefit of angiogenesis

Answer 15

increase surface area for diffusion
improved rate of o2 transfer

Question 16

order of muscle fibre recruitment

Answer 16

progressive of I then IIa then Iix as. intensity increases

Question 17

adaptations to endurance training

Answer 17

change in fibre type composition
increased blood supply
increased mitochondria
increased carb stores
increase fat stores
change in fuel use
increase oxidative enzyme activity

Question 18

myoglobin response

Answer 18

increase in muscle Mb specifically to trained muscle groups up to 80%

Question 19

mitochondrial biogenesis

Answer 19

simplified signal transduction pathway
specific detail will relate directly to different tissues and situations

Question 20

PGC-1a

Answer 20

coactivator responsible for increase in mitochondrial proteins
structural proteins for site of ETC

Question 21

mitochondrial biogenesis process

Answer 21

decrease glycogen / increase ATP
AMPK (activation via protein kinases)
PGC1 increased expression
mitochondrial genes, biogenesis, glycolysis of fatty acids

Question 22

GLUT 4 expression

Answer 22

significantly elevated immediately after a single exercise bout
remains elevated for several hours after
returns within 24hrs
training induced responses increases GULT 4 transcription

Question 23

intramuscular triaglycerol IMTAG

Answer 23

10 males
daily unilateral leg extension
lifted weighted boot
bilateral biopsies

Question 24

intramyocellular lipids

Answer 24

9 untrained healthy men
alternating endurance and interval
3 day standardised diet leading into measurements
increase in response Ito training

Question 25

oxidative enzyme activity

Answer 25

sig changes in SDH activity and CS in trained athletes

Question 26

SDH

Answer 26

oxidises succinate to fumarate

Question 27

CS

Answer 27

catalyses condensation reaction forming citrate

Question 28

Fat oxidation

Answer 28

increase in mitochondrial proteins
increased activities of Krebs cycle and ETC

Question 29

Fat oxidation study

Answer 29

8 untrained women before and after endurance training
12 wks, 5 days/week 1hr @75% vo2 max
vo2max increased 20%
RER decreased significantly at same intensity

Question 30

training intensity and fat

Answer 30

increased aerobic training aerobic power increases (utilise fats at higher intensity)

Question 31

detraining

Answer 31

happens quickly within 6 months

Question 32

cardio vascular and respiratory adaptations

Answer 32

increase max rate of ventilation, Q and SV, extraction of o2 from blood through working muscles