Endurance Training Adaptations Flashcards
Mastery
What is endurance?
training for endurance aims to
what is endurance performance limited by
What is endurance?
* To endure something is to sustain it without impairment
* Training for endurance typically aims to improve e.g.,:
* How far one can go in a given time
* E.g., cycling 1 hour record
* How fast one can go over a given distance
* E.g., marathon
* Endurance performance is limited by fatigue processes
The intensity-duration relationship
How long can max be sustained
Limiters of endurance performance
what shifts the curve
- The duration that exercise can be maintained increases as the power/speed decreases
- Maximum power/speed can only be maintained for a matter of seconds
- Metabolite accumulation due to high rates of anaerobic ATP resynthesis
- Glycogen depletion
- Central fatigue
Shifts the curve
- Decreasing reliance on anaerobic energy input
- Sparing muscle glycogen
Physiological limiters of endurance performance
reduce reliance on what?
conserve what and use what?
what does endurance training focus on improving and use what
The physiological goals of endurance training aim to enhance performance by:
- Reducing reliance on anaerobic energy: Train the body to use more oxygen (oxidative energy) for ATP production, which is more efficient.
- Conserving muscle glycogen: Increase the use of fat (lipid oxidation) for energy at the same intensity, saving glycogen for when it’s really needed.
- In short, endurance training focuses on improving energy efficiency and using more fat instead of glycogen to sustain activity longer
Determinants of the Fick equation and limiters of
endurance performance
what can some adaptations for endurance be: Central, Peripheral
VO2 max limited by what
Critical Power influenced by what
what is CP a stronger indicator of then
Endurance performance depends on oxygen delivery (via cardiac output) and oxygen utilization (a-vO₂ difference), as described by the Fick equation.
Adaptations for endurance can be:
- Central: Related to oxygen delivery (e.g., VO₂max).
- Peripheral: Related to oxygen use in muscles (e.g., critical power, CP).
Key points:
- VO₂max is more limited by central factors.
- CP is more influenced by peripheral factors.
- CP is a stronger predictor of endurance performance than VO₂max.
- In short, improving endurance involves boosting both oxygen delivery and muscle utilization, with CP being more closely tied to actual performance.
The CV system adapts to endurance training by…?
what is oxygen delivery critical for?
CV enhances how? structure, function, from where. CV gets —- to better support…
The cardiovascular (CV) system adapts to endurance training to improve oxygen delivery to muscles, which is essential for sustaining activity.
Key Role: Oxygen delivery is critical for any exercise lasting beyond very short bursts.
Adaptations: The CV system adjusts its structure and function to enhance oxygen transport from the lungs to the muscles.
In short, endurance training strengthens the CV system to better support prolonged muscular activity.
Cardiovascular adaptations
what do all adaptations do
- structural changes, arteries and capillaries
- expansion, PV, RBV
- changes in what of heart, dimensions and contraction
- control of what, vascular
what do some athletes have in relation to their heart
chronic exercise leads to, ventricle, diastolic, SV
= all adaptations facilitating the transport of oxygen from the respiratory system to muscle fibers. These include:
1. Structural changes and increase in number of arteries, arterioles, and capillaries
2. Expansion of red blood cell and plasma volumes
3. Changes in cardiac dimensions and contractility
4. Improvements in the control of vascular vasodilation
Athletes have enlarged ventricles and greater myocardial mass
- An increase in ventricle dimensions
- A higher diastolic reserve due to
increased cardiac compliance - Greater change in SV for a given
change in filling pressure compared to
untrained individuals
Ventricular compliance is greater in athletes
benefits?
- better…
- stroke volume?
- heart pumps how?
***Relationship between Hbmass and VO2 max
Athletes’ hearts are more compliant (less stiff) than those of non-athletes, meaning they can expand more easily.
Compliance: It refers to the heart’s ability to change volume with a given change in pressure.
Benefits:
- Enhanced by structural changes and better relaxation.
- Results in a greater stroke volume (amount of blood pumped) for the same filling pressure.
- In short, athletes’ hearts pump more efficiently due to greater flexibility and capacity.
**A higher Hbmass increases oxygen delivery to muscles, directly supporting a higher VO₂max.
In short, more Hbmass typically means a greater VO₂max, as both are key for efficient oxygen transport and endurance performance.
Endurance training induces changes in blood volume (BV), red blood cell volume (RBCV), and plasma volume (PV):
Overall BV Increase:
- Systemic pressure?
- Venous return
End-diastolic filling
Resting heart rate
Submaximal exercise heart rate
Maximal heart rate
- Plasma Volume (PV): Increases significantly with training, improving blood flow and oxygen delivery.
- Red Blood Cell Volume (RBCV): Also increases but at a slower rate than PV.
- Blood Volume (BV): Overall BV increases due to the combined rise in PV and RBCV, enhancing endurance performance.
Systemic pressure ↑
Venous return ↑
End-diastolic filling ↑
Resting heart rate ↓
Submaximal exercise heart rate ↓
Maximal heart rate ↔ (↓?)
Key Factors for BV Expansion:
Plasma volume and why?
Red blood cell volume and why?
angiotensin II, Vasopressin?
albumin synthesis?
Results? cardiovascular? thermoreg? oxygen delivery
Plasma Volume (PV): Expands rapidly (within hours) due to sodium reabsorption, water retention, and increased fluid intake.
RBC Volume (RBCV): Expands more slowly (over weeks) via erythropoiesis stimulated by exercise and related hormonal changes.
Regulatory Mechanisms:
Hormones like angiotensin II and vasopressin regulate blood pressure
Albumin synthesis aids in maintaining blood osmotic pressure, drawing more fluid into the bloodstream.
Result: Improved cardiovascular function, thermoregulation, and oxygen delivery due to sustained BV increases.
Consequences of elevated BV
Systemic pressure **
Venous return **
End-diastolic filling ***
Resting heart rate
Submaximal exercise heart rate
Maximal heart rate
Systemic pressure ↑
Venous return ↑
End-diastolic filling ↑
Resting heart rate ↓
Submaximal exercise heart rate ↓
Maximal heart rate ↔ (↓?)
*** = lead to higher stroke volume and cardiac output
Key Outcome: Improved stroke volume and cardiac output enable better oxygen delivery and endurance capacity.
Increases in training volume increase WHAT
content?
higher training volumes are associated with what?
Increases in training volume increase mitochondrial content
Number of weekly training sessions
* Higher training volumes were associated with greater increases in mitochondrial content following 6 weeks of endurance training
Peripheral adaptations to endurance training
density of —- in —–?
More ATP thru what?
less reliance on what?
improve metabolic WHAT? and threshold
Fuel Utilization?
Increased Mitochondrial Density:
More ATP production through oxidative phosphorylation (aerobic energy system).
Less reliance on anaerobic energy, meaning less lactic acid buildup and fatigue.
Improved Metabolic Efficiency:
Higher anaerobic threshold/critical intensity, allowing exercise at higher intensities without accumulating lactate.
Smaller metabolic disturbance during submaximal exercise, meaning less strain on the body.
Fuel Utilization:
Reduced reliance on glycolysis (less muscle glycogen use).
Increased fat oxidation, sparing glycogen and enhancing endurance.
Key Outcome: Endurance training enhances muscle’s ability to produce energy aerobically, making exercise more sustainable and efficient
Type I fibre % and capillarity correlate with critical
power
Type I Fibers:
-These are slow-twitch muscle fibers optimized for endurance, using primarily oxidative (aerobic) metabolism.
- A higher percentage of Type I fibers means greater fatigue resistance and more efficient use of oxygen, supporting sustained power output at lower intensities.
Capillary Density:
- A higher capillary density improves oxygen delivery to muscles and facilitates waste removal.
- This allows for greater endurance at submaximal intensities by enhancing the muscle’s ability to maintain aerobic energy production.
Both Type I fibers and increased capillarity contribute to improved endurance performance by boosting the muscle’s ability to utilize oxygen efficiently, thus supporting a higher CP. This leads to better performance during prolonged exercise at moderate intensities
Summary
Increase in muscle oxygen…?
larger hearts and less stiff increases?
increase in blood volume…?
increase in mitochondria…?
Increase in capillary improves…?
Summary
* Increases in muscle oxygen uptake occur through increases in cardiac output and muscle blood flow
- Larger and more compliant hearts facilitate increased cardiac output
- Increase in blood volume helps increase cardiac output
- Increases in mitochondria reduce reliance on anaerobic energy and shift fuel use to rely less on carbohydrates (sparing glycogen)
- Increases in capillarity can improve O2 diffusion to the muscles as well as aid in metabolite removal
