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Flashcards in Exercise Physiology Deck (83):
1

At rest what are the needs of skeletal muscles

Low metabolic needs, 20-30% oxygen uptake

2

What are oxygen requirements of muscle mass at rest

75ml/min

3

What are oxygen requirements of muscle mass during severe exercise

300ml/min

4

Why are glucose anf fats mobilised for oxidation

To yield ATP for muscle contraction

5

Which systems undergo change in order to meet metabolic needs

1. Cardiovascular system

2. Respiratory system

3. Endocrine system

6

How can the amount of work in a performance task be assessed

By measuring the increase in oxygen uptake compared to rest

7

What is VO2max

The measure of the maximum volume of oxygen that an athlete can use.

 

8

What si the single best measure of cardiovascular fitness

VO2max

9

What is isometric (static) exercise

Constant muscle length and increased tension

10

What is dynamic exercise

Rhythmic cycles of contraction and relaxation; change in muscle length

11

How does the body respond to isometric and dynamic exercise

Through adjustments to the cardiovascular system and respiratory system

12

What is moderate exercise

Steady state attained in 2-3 minutes, can talk comfortably

13

What is heavy exercise

Steady state not attained for 10-20 minutes, can talk but less comfortably

14

What is marathon pace

Heavy exercise

15

Where is the lactate threshold reached

During heavy exercise

16

What is severe exercise

'Working on borrowed time'- fatigue is inevitable and highly predictable

17

Where is critical power/ speed

In severe exercise

18

What is extreme exercise

Maximum effort for 2 minutes or less

19

What are the two types of respiration

Aerobic and anaerobic

20

Which type of respiration is long term and happens during exercise such as swimming or cycling

Aerobic 

21

Which type of respiration is short term and happens during exercise such as weight lifting or sprinting

Anaerobic

22

How does anaerobic respiration allow muscles to generate force in the absence of oxygen

The combined actions of ATP/ creatine phosphate and glycolysis 

23

Why is anaerobic respiration less efficient

Lactic acid is produced

24

When is anaerobic respiration prevelant

During the early minutes of high-intensity exercise

25

How do muscles generate force during aerobic respiration

They use oxygen through oxidative phosphorylation

26

Which type of respiration yields more ATP

Aerobic

27

When is aerobic respiration the primary method of energy production

During endurance events

28

Which type of muscle fibres are in use during anaerobic exercise

Fast twitch muscle fibres

29

Describe the characteristics of fast twitch muscle fibres

  • Large in diameter
  • Light in colour (low myoglobin)
  • Surrounded by few capillaries
  • Relatively few mitochondria
  • High glycogen content (have a ready supply of glucose for glycolysis)

30

Describe the characteristics of anaerobic exercise

  • Sprinting, weight lifting
  • Short duration, great intensity
  • Creatine phosphate and glycogen from muscle fibres
  • Fast-twitch muscle fibres: IIa/IIb

31

Describe the characterstics of slow twitch muscle fibres

  • Red in colour (high myoglobin)
  • Surrounded by many capillaries
  • Numerous mitochondria
  • Low glycogen content
  • Also metabolise fatty acids and proteins- broken down into acetyl CoA that enters the Krebs cycle

32

Describe the features of aerobic exercise

  • Long-distance running, swimming
  • Prolonged but at lower intensity
  • Fuels stored in muscle, adipose tissue and liver
  • Major fuels used vary with the intesnsity and duration of exercise (glucose early, FFA later)
  • Slow twitch muscle fibres

33

Which type of muscle fibres are used in aerobic exercise

Slow twitch muscle fibres

34

What is oxygen consumption proportional to

Work done

35

What is caused by oxyegn consumption not immediately rising to match energy requirements

An oxygen deficit

36

What happens post exercise

ATP and CP are resynthesised. 

Excess lactate is resynthesised into glucose and glycogen

37

What contributes to fatigue

Lactate formation

38

What impairs oxidative enzymes

Lactate formation

39

What happens when oxygen consumption is above aerobic energy production

Energy production is supplemented by anaerobic mechanisms. 

 

40

What is anerobic threshold

The point at which lactate starts to accumulate in teh blood

41

What can be used to indicate a potential for endurance exercise

Anaerobic threshold

42

What provides most of the energy for muscular exercise

Carbohydrates

43

What contributes small amounts of enegy for muscular exercise

Fats

44

What is an insignificant source of energy for muscular exercise

Protein

45

What is respiratory quotient

RQ= Vol CO2 produced : Vol O2 used

Volume of carbon dioxide produced to the volume of oxygen used per unit time by the body under steady state conditions

46

Describe what happens to plasma glucose levels during exercise

Plasma glucose levels fall very little unless severe and prolonged exercise occurs

47

By how much do plasma glucose levels fall over 3 hours of continuous exercise

by 10%

48

Where is glucose derived from

Glycogen stores in skeletal muscle and liver

49

What does adrenaline stimulate

Glycogenolysis

50

What does prolonged exercise stimulate

Gluconeogenesis

51

What are gluconeogenesis and lipolysis stimulated by

Cortisol, noradrenaline, adrenaline and growth hormone

52

What is cardiac output at rest

5 L/min

53

What is cardiac output during heavy exercise

38 L/min

54

How much cardiac output is distributed to exercising muscles in heavy exercise

80%

55

What happens to blood flow to the brain during heavy exercise

It remains constant

56

What happens to blood flow to the renal and splanchnic system during heavy exercise

Circulation declines

57

What adjustments occur during heavy exercise

There are adjustments to heart rate and stroke volume which has effects of regional blood flow and blood pressure

58

What happens to the nervous system during exercise

The vagal (parasympathetic) activity declines and the sympathetic increases

59

What does an increase in symapthetic nerve activity during exercise result in

An increase in heart rate and mobilisation of blood from large veins. Causing an increase in stroke volume and more complete emptying of the ventricles

60

What happens to inactive tissues

(regional blood flow)

Vasoconstriction due to noradrenaline and sympathetic activity

61

What happens to active tissue

(regional blood flow)

Vasodilation of the arterioles due to the presence of metabolites and adrenaline. Results in more blood being brought to the tissue

62

Which substances are metabolites

CO2, ADP and organic acids

63

What is SVR

Systemic vascular resistance

64

What affect do increased metabolites have on blood pressure

Vasoldilation and decreased SVR

65

What affect does increased sympathetic activity and secretion of noradrenaline have on BP

Noradrenaline causesvasoconstriction and increased SVR

66

What does increased sympathetic activity and secretion of adrenaline do to blood presure

Adrenaline causes vasodialtion of the muscles and capillaries and decreased SVR

67

What is the overall effect on SVR during exercise

SVR is decreased

68

What is blood pressure

BP = CO x SVR

69

What does a decrease in SVR result in

An increase in the force of ventricular contraction which casues an increase in systolic pressure (diastolic pressure is stable)

70

Summarise the cardiovascular changes that occur during exercise

Increased exercise = increased sympathetic output anf build up of metabolites.

Increased sympathetic output = increased cardiac output, vasodilation in skeletal muscles, vasocostriction in viscera

Increased metabolites = vasodilation in active tissue

71

What effect does training have on performance

Training improves performance

72

What 3 things are required during training

Regular exercise of:

  1. appropriate intensity
  2. appropriate duration
  3. appropriate frequency

73

What will regular training with strenuous exercise result in

  1. Lowering resting HR
  2. Increasing cardiac output
    1. Increasing the size of the heart

74

What do cardiovascular changes result in

An increase in the maximal O2 uptake, capacity for physical work is increased

75

What effect does training have on heart size

  1. Long term aerobic training increases the heart's mass and volume. 
  2. Enlargement occurs due to increased size of the left cavity and modest thickening of its walls
  3. This improves the heart's stroke volume
  4. Accelerated protein synthesis leads to individual myofibrils increasing in number and thickening

76

What effect does training have on stroke volume

An endurance athlete has a large stroke volume at both rest and exercise. The greatest increase in stroke volume occurs during the transition from rest to moderate exercise

77

What effect does training have on heart rate

  1. As exercise intensity increases the HR of athletes accelerates to a lesser extent that untrained
  2. Athletes achieve higher maximum O2 uptake before reaching submaximal HR
  3. Larger stroke volume accounts for lower exercise HR
  4. If the heart pumps large quantity of blood with each beat then adequate devlivery of blood (O2) to the active muscles requires only small increase in HR

78

What effect does training have on cardiac output (CO)

  • Increase in maximum CO represents most significant change
  • CO = HR x SV
  • CO increases due to imporved stroke volume.
  • CO increases in order to meet the oxygen requirements of exercising muscle

79

What is athlete's heart

A normal response to healthy exercise or pregnancy

80

What does athlete's heart result in

An increase in heart's muscle mass and pumping ability (walls and chamber size increase). Left ventricular mass is up to 60% greater than in untrained subjects

81

What does pathological hypertrophy lead to

An increase in muscle mass (not as increase in heart's pumping ability) due to accumulation of myocardial scarring. Can increase mass of heart by up to 150%

82

How does exercise reduce cardiovascular disease

  1. Improves the heart's contractility, work capacity and circulation
  2. Improves the ratio of blood lipids (HDL/ LDL/ triglycerides)
  3. Controls and prevents moderate hypertension
  4. Controls weight, reduces body fat and increases muscle mass
  5. Alleviates stress and decreases cigarette smoking
  6. Reduces insulin resistance

83