Exercise Physiology Flashcards

1
Q

At rest what are the needs of skeletal muscles

A

Low metabolic needs, 20-30% oxygen uptake

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2
Q

What are oxygen requirements of muscle mass at rest

A

75ml/min

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3
Q

What are oxygen requirements of muscle mass during severe exercise

A

300ml/min

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4
Q

Why are glucose anf fats mobilised for oxidation

A

To yield ATP for muscle contraction

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5
Q

Which systems undergo change in order to meet metabolic needs

A
  1. Cardiovascular system
  2. Respiratory system
  3. Endocrine system
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6
Q

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

A

By measuring the increase in oxygen uptake compared to rest

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7
Q

What is VO2max

A

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

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8
Q

What si the single best measure of cardiovascular fitness

A

VO2max

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9
Q

What is isometric (static) exercise

A

Constant muscle length and increased tension

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10
Q

What is dynamic exercise

A

Rhythmic cycles of contraction and relaxation; change in muscle length

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11
Q

How does the body respond to isometric and dynamic exercise

A

Through adjustments to the cardiovascular system and respiratory system

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12
Q

What is moderate exercise

A

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

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13
Q

What is heavy exercise

A

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

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14
Q

What is marathon pace

A

Heavy exercise

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15
Q

Where is the lactate threshold reached

A

During heavy exercise

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16
Q

What is severe exercise

A

‘Working on borrowed time’- fatigue is inevitable and highly predictable

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17
Q

Where is critical power/ speed

A

In severe exercise

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18
Q

What is extreme exercise

A

Maximum effort for 2 minutes or less

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19
Q

What are the two types of respiration

A

Aerobic and anaerobic

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20
Q

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

A

Aerobic

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21
Q

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

A

Anaerobic

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22
Q

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

A

The combined actions of ATP/ creatine phosphate and glycolysis

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23
Q

Why is anaerobic respiration less efficient

A

Lactic acid is produced

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24
Q

When is anaerobic respiration prevelant

A

During the early minutes of high-intensity exercise

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25
Q

How do muscles generate force during aerobic respiration

A

They use oxygen through oxidative phosphorylation

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26
Q

Which type of respiration yields more ATP

A

Aerobic

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27
Q

When is aerobic respiration the primary method of energy production

A

During endurance events

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28
Q

Which type of muscle fibres are in use during anaerobic exercise

A

Fast twitch muscle fibres

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29
Q

Describe the characteristics of fast twitch muscle fibres

A
  • 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)
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30
Q

Describe the characteristics of anaerobic exercise

A
  • Sprinting, weight lifting
  • Short duration, great intensity
  • Creatine phosphate and glycogen from muscle fibres
  • Fast-twitch muscle fibres: IIa/IIb
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31
Q

Describe the characterstics of slow twitch muscle fibres

A
  • 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
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32
Q

Describe the features of aerobic exercise

A
  • 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
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33
Q

Which type of muscle fibres are used in aerobic exercise

A

Slow twitch muscle fibres

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34
Q

What is oxygen consumption proportional to

A

Work done

35
Q

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

A

An oxygen deficit

36
Q

What happens post exercise

A

ATP and CP are resynthesised.

Excess lactate is resynthesised into glucose and glycogen

37
Q

What contributes to fatigue

A

Lactate formation

38
Q

What impairs oxidative enzymes

A

Lactate formation

39
Q

What happens when oxygen consumption is above aerobic energy production

A

Energy production is supplemented by anaerobic mechanisms.

40
Q

What is anerobic threshold

A

The point at which lactate starts to accumulate in teh blood

41
Q

What can be used to indicate a potential for endurance exercise

A

Anaerobic threshold

42
Q

What provides most of the energy for muscular exercise

A

Carbohydrates

43
Q

What contributes small amounts of enegy for muscular exercise

A

Fats

44
Q

What is an insignificant source of energy for muscular exercise

A

Protein

45
Q

What is respiratory quotient

A

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
Q

Describe what happens to plasma glucose levels during exercise

A

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

47
Q

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

A

by 10%

48
Q

Where is glucose derived from

A

Glycogen stores in skeletal muscle and liver

49
Q

What does adrenaline stimulate

A

Glycogenolysis

50
Q

What does prolonged exercise stimulate

A

Gluconeogenesis

51
Q

What are gluconeogenesis and lipolysis stimulated by

A

Cortisol, noradrenaline, adrenaline and growth hormone

52
Q

What is cardiac output at rest

A

5 L/min

53
Q

What is cardiac output during heavy exercise

A

38 L/min

54
Q

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

A

80%

55
Q

What happens to blood flow to the brain during heavy exercise

A

It remains constant

56
Q

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

A

Circulation declines

57
Q

What adjustments occur during heavy exercise

A

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

58
Q

What happens to the nervous system during exercise

A

The vagal (parasympathetic) activity declines and the sympathetic increases

59
Q

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

A

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
Q

What happens to inactive tissues

(regional blood flow)

A

Vasoconstriction due to noradrenaline and sympathetic activity

61
Q

What happens to active tissue

(regional blood flow)

A

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

62
Q

Which substances are metabolites

A

CO2, ADP and organic acids

63
Q

What is SVR

A

Systemic vascular resistance

64
Q

What affect do increased metabolites have on blood pressure

A

Vasoldilation and decreased SVR

65
Q

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

A

Noradrenaline causesvasoconstriction and increased SVR

66
Q

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

A

Adrenaline causes vasodialtion of the muscles and capillaries and decreased SVR

67
Q

What is the overall effect on SVR during exercise

A

SVR is decreased

68
Q

What is blood pressure

A

BP = CO x SVR

69
Q

What does a decrease in SVR result in

A

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

70
Q

Summarise the cardiovascular changes that occur during exercise

A

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
Q

What effect does training have on performance

A

Training improves performance

72
Q

What 3 things are required during training

A

Regular exercise of:

  1. appropriate intensity
  2. appropriate duration
  3. appropriate frequency
73
Q

What will regular training with strenuous exercise result in

A
  1. Lowering resting HR
  2. Increasing cardiac output
    1. Increasing the size of the heart
74
Q

What do cardiovascular changes result in

A

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

75
Q

What effect does training have on heart size

A
  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
Q

What effect does training have on stroke volume

A

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
Q

What effect does training have on heart rate

A
  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
Q

What effect does training have on cardiac output (CO)

A
  • 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
Q

What is athlete’s heart

A

A normal response to healthy exercise or pregnancy

80
Q

What does athlete’s heart result in

A

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
Q

What does pathological hypertrophy lead to

A

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
Q

How does exercise reduce cardiovascular disease

A
  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
Q
A