24-30 Hargreaves Flashcards Preview

Muscle Phys > 24-30 Hargreaves > Flashcards

Flashcards in 24-30 Hargreaves Deck (19):
1

24

What is the oxygen deficit?

Why does it occur?

What are the determinants of VO2 kinetics?

  • Gradual increase in oxidative phosphorylation
  • Delay in oxygen delivery and mitochondrial respiration
  •  
  • Ca2+ activation
  • [ATP]/[ADP].[Pi] and [NAD+]/[NADH]
  • mitochondrial PO2

2

24

What is VO2 drift?

Why does it occur?

  • Slow upward drift of VO2
  • Prolonged strenuous exercise - active muscles

3

24

What is EPOC?

Why does it occur?

  • Excess post-exercise oxygen consumption
  •  
  • Slow decline in O2 demands
  • CP resynthesis, muscle glycogen resynthesis
  • Elevated temperature and hormones

4

24 What is the metabolic fate of lactate?

  • Active recovery enhances removal, conversion to other metabolites
  • Does not increase VO2 or cause muscle soreness

5

25 What is the Fick equation?

  • VO2 = Q x (CaO2 – CvO2)
  • Q - cardiac output
  • (CaO2 – CvO2) - oxygen extraction, arteriovenous difference

6

25

What are the metabolic vasodilators?

  • K+ - depolarisation
  • H+ - metabolism
  • Adenosine - ATP
  • ATP
  • ROS
  • NO

7

25

What cardiac changes do athletes have?

  • Bigger heart – cardiac muscle and chambers bigger
  • Higher SV --> lower HR
  • Maximal HR lower – SA node pacemaker activity changes

8

25

Why does SV decrease during prolonged exercise?

High HR

9

25

What is cardiovascular drift?

What is this due to?

  • Increased HR and decreased SV
  • Hyperthermia and dehydration

10

27

What happens to respiration during exercise?

Why does EIAH occur?

Breathing frequency and tidal volume increase

Desaturate as brain needs oxygen, diaphragmatic fatigue, respiratory muscle work

11

27

What is exercise hyperpnoea?

Factors?

  • Increased depth and rate of breathing
  • Motor cortex activation, CO2 flux to lung

12

28

What factors influence maximal oxygen uptake?

  • O2 delivery - main rate limiting, muscle mitochondrial capacity exceeds
  • Central circulation - blood volume
  • Muscle diffusion capacity - capillary density
  • Muscle oxidative capacity

13

29

What controls sweat during exercise?

  • Sympathetic cholinergic nerves
  • Temperature - core and skin
  • Sweat gland
  • Dehydration

14

29

What happens during heat stress in exercise?

  • Resting CO increases significantly - blood flow to skin
  • Increased glycogen utilisation, but impaired exercise capacity
  • Central fatigue - reduced voluntary activation of muscle

15

29

What strategies can be used to enhance exercise performance in the heat?

  • Heat acclimatisation
  • Pre-cooling
  • Fluid ingestion - increased SV and CO --> decreased HR, many benefits

16

30

What are potential factors in fatigue?

  • Central fatigue
  • Ionic disturbances
  • Substrate depletion, metabolite accumulation
  • Fluid losses and hyperthermia

17

30

How is pH involved in exercise?

  • Exercise increases metabolic acid
  • Induced alkalosis - increased the removal of H+
  • H+, unsure if fatigue or protective

18

30

When Fe is repleted:

What does VO2 max track?

What does endurance track?

  • Haematocrit - O2 delivery
  • Muscle oxidative capacity

19

30

How can fuels be used to maximise success?

  • Glycogen loading
  • Fluids
  • Pre cooling