ENDURANCE Flashcards

1
Q

Marathon World Record

A
  • dropping almost 4x faster than preceding decades
  • current record = 2:01:09 Eluid Kipchoge, Berlin, 2022
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2
Q

Pillars to Sub-2 Hour Marathon Success

A
  • athlete selection (human physiology and genes)
  • course and environment
  • training (coaching, exercise physiology)
  • nutrition / hydration
  • equipment
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3
Q

Acute Effects to Aerobic Exercise - Brain

A
  • neural activity = increase or decrease
  • blood flow = no change
  • blood distribution = increase
  • metabolism = increase or decrease
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4
Q

Acute Effects to Aerobic Exercise - Lungs

A
  • ventilation and gas exchange = increase
  • blood flow = increase
  • blood distribution = increase
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5
Q

Acute Effects to Aerobic Exercise - Heart

A
  • cardiac output = increase
  • coronary blood flow = increase
  • oxygen consumption = increase
  • blood flow distribution = increase
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6
Q

Acute Effects to Aerobic Exercise - Blood Cells

A
  • haemoconcentration (red blood cell movement increase) = increase
  • oxygen content = increase
  • levels of energy substances = no change / increase
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7
Q

Acute Effects to Aerobic Exercise - Muscle Fibres

A
  • metabolism and blood flow = increase
  • oxygen extraction and consumption = increase
  • mechanical strains = increase
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8
Q

Acute Effects to Aerobic Exercise - Capillaries

A
  • arterial dilation = increase
  • capillary pressure and energy substrate exchange = increase
  • venoconstriction = increase
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9
Q

Acute Effects to Aerobic Exercise - Pancreas, Gut & Kidneys

A
  • blood flow = decrease
  • metabolism = increase
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10
Q

Acute Effects to Aerobic Exercise - Bone Marrow

A
  • blood flow = no change / increase
  • mechanical strain = increase
  • release of stem cells = increase
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11
Q

Acute Effects to Aerobic Exercise - Liver

A
  • blood flow = decrease
  • metabolism = increase
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12
Q

Acute Effects to Aerobic Exercise - Adipose Tissue

A
  • blood flow = increase / no change / decrease
  • metabolism = increase
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13
Q

Acute Effects to Aerobic Exercise - Skin

A
  • blood flow = increase / no change / decrease
  • metabolism = ?
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14
Q

Endurance Definition

A

‘The act of sustaining prolonged stressful effort’. It is limited by the capacity of the C-R system (heart, blood vessels, blood, lungs) to deliver O2 and excrete CO2 and in the ability of muscle to metabolise fuels aerobically

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15
Q

Determinants of Endurance Performance

A
  • maximum rate a subject can exercise at (VO2max)
  • the highest % of this rate of the subject can exercise at for a sustained period of time (% of VO2max)
  • economy of subject carrying out repetitive muscular actions (O2 cost per unit speed)
  • choice of energy pathways that are employed to power exercise at the optimal achievable %VO2max (i.e., anaerobic glycolysis vs oxidative phosphorylation
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16
Q

Factors Determining Pace

A
  • rate of anaerobic energy expenditure (VO2max, %of VO2max that can be sustained, anaerobic threshold)
  • economy (VO2 unit per speed)
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17
Q

Physiological Factors Determining Success in Cycling

A
  1. VO2max
  2. %VO2max
  3. choice of fuel (fat: CHO; CHO-oxid: non-oxid combustion
  4. O2 economy
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18
Q

Cycling Endurance (VO2 equation)

A
  • VO2 = Q x a-vO2 difference
  • Q (cardiac output) = HR (heart rate) x SV (stroke volume)
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19
Q

Aerobic Ability - Ball et al., 2017

A

Chris Froome:
VO2 peak = 5.91 L/min-1 (84ml/kg/min)
PPO = 525W
Gross Efficiency = 23.3% (average values 22%)

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20
Q

Factors Determining Aerobic Performance

A
  • blood volume, SNS + PNS, Mitochondrial & capillary density, respiratory capacity
  • venous return, speed of O2 use
  • max HR, max SV, Hb conc, O2 extraction of muscle
  • cardiac output, a-vO2 difference
  • genetics + training
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21
Q

VO2max Definition

A

‘the maximum rate of oxygen uptake under normal conditions of ambient temperature and pressure for a subject utilising the majority of muscle mass in a dynamic exercise activity’

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22
Q

Criteria to use VO2peak instead of VO2max

A
  • plateau in VO2 when plotted against work intensity
  • final RER >1.10
  • heart rate within 10 beats.min
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23
Q

Criteria to use VO2peak instead of VO2max

A
  • plateau in VO2 when plotted against work intensity
  • final RER >1.10
  • heart rate within 10 beats.min-1 of age predicted max
  • final lactate value of >10mmol.L-1 (this is variable)
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24
Q

VO2 max and Marathon Times - Farrell et al., 1979

A
  • VO2max is correlated with marathon times
  • time = 2.17-3.49
  • r value = 0.91
  • still large unaccounted for variations in people with same VO2max
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25
Billat et al., 1994
- velocity at VO2max helps determine race pace - athletes with the same VO2max run at different speeds so velocity at VO2max (vVO2max) is an important determinant of performance - time spent at VO2max (tlimvVO2max) determines performance
26
Endurance performance determinants
- anaerobic metabolism also determines performance - lactate threshold shows strong relationship to performance - determining maximum lactate steady state (MLSS) can determine optimal race pace
27
Morgan et al., 1989
- athletes running at same sub-max speed show differing O2 cost - amongst athletes of similar ability VO2max is poor indicator of performance - performance time is related to VO2max, AT and RE showing link between state of physical training and predicted performance time - appropriate increased measured training volume mostly leads to decreased performance times
28
Endurance Training Definition - ACMS Position Stand, 1998
'when exercise involving large muscle groups is performed 3-5d/wk at an intensity between 40/50-80% VO2max for 20-60+ mins over several weeks it leads to functional changes that improve the rate of energy supply to demand, essential to perform endurance sports at a high level'
29
Endurance Training - Non-Cardiovascular Effects - Skeletal Muscle
- oxidative phosphorylation = increase - muscle hypertrophy - calcium handling = increase
30
Endurance Training - Non-Cardiovascular Effects - Ventilation
- vital capacity = increase - tidal volume = increase - max inspiratory and expiratory factor = increase
31
Endurance Training - Non-Cardiovascular Effects - Hemorrheology
- blood viscosity = decrease - coagulability = decrease - oxygen transport capacity = increase
32
Endurance Training - Cardiac Effects - Normal LV function
- I/R protection - prevention of age-related diastolic dysfunction - physiologic hypertrophy to training
33
Endurance Training - Cardiac Effects - Systolic Heart Failure
- reverse LV-remodelling - LV ejection fraction = increase - improved neurohormonal activation - arrhythmia prevention
34
Endurance Training - Cardiac Effects - Diastolic Heart Failure
- prevention of diastolic function - improvement of LV relaxation and compliance in HFNEF
35
Endurance Training - Cardiac Effects - Cardiac Values
- prevention of value degeneration - prevention of calcification
36
Endurance Training - Vascular Effects - Aorta
- aortic stiffness = decrease - aortic compliance = increase
37
Endurance Training - Vascular Effects - Conduit Vessel
- endothelial vasodilation = increase - NO production = increase - oxidative stress = decrease
38
Endurance Training - Vascular Effects - Resistance Vessel and Microcirculation
- vasculogenesis by EPCs sensitivty to adenosine = increase
39
Endurance Training - Vascular Effects - Capillary Bed
- capillary vessel formation = increase
40
Endurance Training - Vascular Effects - Venous Circulation
- venular capillaries = increase
41
Endurance Training - Vascular Effects - Pulmonary Artery
- endothelial function = increase - pulmonary artery pressure = decrease - in chronic heart failure
42
Endurance Training -Neurohormonal and Autonomic Effects
- sympathetic tone = decrease - parasympathetic tone = increase
43
Endurance Training -Neurohormonal and Autonomic Effects - In CHF
- norepinephrine - angiotensin II - ANP, BNP
44
Endurance Training -Neurohormonal and Autonomic Effects - Antiarrythmic Effects
- normalisation of heart rate variability - shortened action potential duration - hyperpolarization - attenuated automacity
45
Systemic Effects of Endurance Training - Skeletal Muscle
- hypertrophy - hyperplasia - fibre type switching
46
Systemic Effects of Endurance Training - Vascular
- increased flow - increased vasoreactivity - increased angiogenesis
47
Systemic Effects of Endurance Training - Metabolism
- increased insulin sensitivity - increased oxidative phosphorylation - increased mitochondrial biogenesis - increased adipose 'browning'
48
Central Adaptation to Endurance Training - Blood Volume
- plamsa volume and Hb increase
49
Central Adaptation to Endurance Training - Stroke Volume
- greater ventricular volume alongside greater myocardial contractility
50
Central Adaptation to Endurance Training - Heart Rate
- decrease at rest and sub-max-ex, no change in MHR
51
Central Adaptation to Endurance Training - Cardiac Output
- greater SV leads to greater max Q
52
Central Adaptation to Endurance Training - Blood flow and Distribution
- increase in total muscle blood flow during max-ex but decrease during sub-max-ex
53
Central Adaptation to Endurance Training - Oxygen Extraction
- increase extraction of O2 and a-VO2 difference
54
Central Adaptation to Endurance Training - Arterial Blood Pressure
- decrease in SBP and DBP at rest and submax
55
Central Adaptation to Endurance Training - Ventilation
- greater tidal volume and breathing frequency leads to greater overall ventilation during max-ex, but decreases during sub-max-ex
56
Central Adaptations to Endurance Training
- myocardial changes - hypervolemia - angiogenesis - respiration
57
Trained Heart - Scharharg et al., 2002
- the max pumping rate of the heart determines VO2max
58
Trained Heart - Ekbom, 1968
- endurance in trained athletes increase Q from 5 - 40L/min (Untrained increase from 5 - 20L/min) - increased cardiac performance during ex is related to eccentric left ventricular cardiac hypertrophy
59
Benefits of Exercise to Endothelium
- shear stress - cyclin strain - myokines (e.g., IL-6) - adipokines (e.g. adiponectin) - insulin
60
Tesch et al., 1984 - aerobic exercise
- regular aerobic exercise stimulates new capillary growth - allows a slower passage pf Hb facilitating better O2 extraction
61
Chronic Microvascular Adaptations - Direct Exercise
- blood vessels supplying active skeletal muscle (O2, glucose and O2 in; CO2, H+and CO2 out - increased vasodilator signalling - increased capillary density - increased insulin/PI3K signalling
62
Chronic Microvascular Adaptations - Indirect Exercise
- decreased HbA1c, decreased insulin secretion and decreased micro complications
63
Hypervolemia (Increase in Blood Volume) - Convertino et al., 1980
- 8% increase in blood volume accounted for by 12% increase in plasma volume following 8 consecutive days training - pv in first days of training account for bv increase - rbc can take > 4 weeks to increase in response to training - increased bv is due to initial protein and fluid shifts from extra- to intra-vascular space followed by increase in total body water
64
Plasma Volume Expansion - Convertino et al., 1991
- every 1% increae in PV leads to a similar % decrease in HR with endurance training - alters the frank-starling mechanism - hypervolemia leads to greater central venous pressure leads to end diastolic volume (cardiac preload) leads to greater stroke volume - hypervolemia increases Qmax and increased VO2max
65
Pulmonary Adaptations to Endurance Training
- reduce respiratort work at a given ex-intensity, lends more O2 to non-respiratory active skeletal musculature - max-ex: as Ve= Fb x TV, increase in VO2 max raises O2 requirement and elimination of CO2 via greater alveolar ventilation rate - sub-max-ex: endurance training reduces ventilatory equivalent for O2 (Ve/VO2) during sub-max-ex and lowers % of total O2 cost of breathing - decrease in O2 cost of breathing by ventilatory muscle enhances endurance by reducing fatigue and the non-used O2 by respiratory muscles is available elsewhere
66
Babcock et al., 1998 - Endurance Training Benefits Ventilatory Muscles
- inspiratory muscle fatigue occurs during prolonged intense exercise - enhances ability to sustain high levels of sub-max ventilation. training causes less disruption in whole-body hormonal and acid base balance that could negatively effect muscle function - increases inspiratory muscle capacity to generate force and sustain a given level of inspiratory pressure - performance is benefitted by reduced energy demand due to less respiratory work, reduced lactate production by ventilatory muscles and improve how ventilatory muscles metabolise as fuel - anaerobic threshold can be determined by ventilatory threshold, related to performance
67
Muscle Adaptations to Endurance Training
- hypertrophy - fuel storage - mitochondria
68
Costill et al., 1976 - Hypertrophy of Type 1 Muscle Fibres
- gastrocnemius muscle type 1 fibres; elite endurance runners 79%, non-elite middle distance runners 62%, and untrained 58% - fibre size in elite runners 30% bigger - genetic predisposition in determining muscle fibre response to ex shown through small magnitude of change with training
69
Andersen and Henriksson, 1977 - Skeletal Muscle Adaptations to Regular Aerobic Exercise
- 8 weeks of endurance training led to a conversion of type 11b to 11a
70
Maughan et al., 1997 - Fuel Storage and Endurance Training
- muscle glycogen storage is increased (due to increased sensitivity of muscle insulin receptors) - insulin promotes glucose uptake via GLUT4 transporters (25% higher in endurance trained muscle)
71
Fuel Storage and Endurance
- glycolytic enzymes are increased - training increases capacity for glycogen provided adequate time has elapsed and sufficient CHO is consumed
72
Hurley et al., 1986 - Fuel Storage and Endurance
- muscle TG concentrations significantly increase with endurance training and are used more - aerobic training reduces muscle glycogen use and plasma glucose oxidation during ex but increases the use of fat during ex
73
Mendenhall et al., - Fuel Storage and Endurance
- lower RER and muscular RQ - smaller rise in plasma FFA concentration - lower rate of use of blood glucose by muscle - reduced accumulation of muscle lactate - increased oxidation of lipid relative to CHO -
74
Mitochondrial Size and Density
- mitochondria don't limit VO2max but influence performance by selection of energy used - greater mitochondrial (conc and size) means greater pyruvate oxidation and less lactate in cytosol at any given exercise intensity - greater mitochondria improves efficient ATP resynthesis via oxidation (more than 30mol ATP from OP, 3mol ATP produced by glycolysis) - more mitochondria improves fat oxidation - increased mitochondria number and size improves aerobic ATP production
75
Kiessling et al., 1971 - Muscle Mitochondria Density and Enzyme Activity
- mitochondria size is increased (~14-40%) in trained muscle - mitochondrial number increased (120%) in human vastus lateralis of trained men following 28 weeks training
76
Holloszy et al., 1970 - Muscle Mitochondria Density and Enzyme Activity
- trained muscle mitochondria increased capacity to generate ATP aerobically via oxidative phosphorylation - TCA cycle enzymes increased by 34-101% after treadmill training - isocitrate dehydrogenase increased by 90% - cytochrome C content increased 102%
77
Gollnick and Saltin, 1983 - Muscle Mitochondria Density and Enzyme Activity
- relationship between VO2max and and SDH (mitochondrial marker)