ENDURANCE Flashcards
Marathon World Record
- dropping almost 4x faster than preceding decades
- current record = 2:01:09 Eluid Kipchoge, Berlin, 2022
Pillars to Sub-2 Hour Marathon Success
- athlete selection (human physiology and genes)
- course and environment
- training (coaching, exercise physiology)
- nutrition / hydration
- equipment
Acute Effects to Aerobic Exercise - Brain
- neural activity = increase or decrease
- blood flow = no change
- blood distribution = increase
- metabolism = increase or decrease
Acute Effects to Aerobic Exercise - Lungs
- ventilation and gas exchange = increase
- blood flow = increase
- blood distribution = increase
Acute Effects to Aerobic Exercise - Heart
- cardiac output = increase
- coronary blood flow = increase
- oxygen consumption = increase
- blood flow distribution = increase
Acute Effects to Aerobic Exercise - Blood Cells
- haemoconcentration (red blood cell movement increase) = increase
- oxygen content = increase
- levels of energy substances = no change / increase
Acute Effects to Aerobic Exercise - Muscle Fibres
- metabolism and blood flow = increase
- oxygen extraction and consumption = increase
- mechanical strains = increase
Acute Effects to Aerobic Exercise - Capillaries
- arterial dilation = increase
- capillary pressure and energy substrate exchange = increase
- venoconstriction = increase
Acute Effects to Aerobic Exercise - Pancreas, Gut & Kidneys
- blood flow = decrease
- metabolism = increase
Acute Effects to Aerobic Exercise - Bone Marrow
- blood flow = no change / increase
- mechanical strain = increase
- release of stem cells = increase
Acute Effects to Aerobic Exercise - Liver
- blood flow = decrease
- metabolism = increase
Acute Effects to Aerobic Exercise - Adipose Tissue
- blood flow = increase / no change / decrease
- metabolism = increase
Acute Effects to Aerobic Exercise - Skin
- blood flow = increase / no change / decrease
- metabolism = ?
Endurance Definition
‘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
Determinants of Endurance Performance
- 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
Factors Determining Pace
- rate of anaerobic energy expenditure (VO2max, %of VO2max that can be sustained, anaerobic threshold)
- economy (VO2 unit per speed)
Physiological Factors Determining Success in Cycling
- VO2max
- %VO2max
- choice of fuel (fat: CHO; CHO-oxid: non-oxid combustion
- O2 economy
Cycling Endurance (VO2 equation)
- VO2 = Q x a-vO2 difference
- Q (cardiac output) = HR (heart rate) x SV (stroke volume)
Aerobic Ability - Ball et al., 2017
Chris Froome:
VO2 peak = 5.91 L/min-1 (84ml/kg/min)
PPO = 525W
Gross Efficiency = 23.3% (average values 22%)
Factors Determining Aerobic Performance
- 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
VO2max Definition
‘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’
Criteria to use VO2peak instead of VO2max
- plateau in VO2 when plotted against work intensity
- final RER >1.10
- heart rate within 10 beats.min
Criteria to use VO2peak instead of VO2max
- 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)
VO2 max and Marathon Times - Farrell et al., 1979
- 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
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
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
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
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’
Endurance Training - Non-Cardiovascular Effects - Skeletal Muscle
- oxidative phosphorylation = increase
- muscle hypertrophy
- calcium handling = increase
Endurance Training - Non-Cardiovascular Effects - Ventilation
- vital capacity = increase
- tidal volume = increase
- max inspiratory and expiratory factor = increase