Chronic Adaptations

With reference to the content notes, please answer the following questions:

What are chronic adaptations?

long-term physiological changes that occur as a result of participating in a training program. The types of adaptations that lead to improved performance are dependent on the specific type of training that is undertaken. Training needs to be completed regularly over an extended period of time. (6-8 weeks, three times a week) Chronic training adaptation may occur at the cardiovascular and respiratory systems, and/or within the neuromuscular system.

What are the factors that impact on the chronic adaptations that can be obtained from training?

The type and method of training undertaken - whether it be aerobic, anaerobic or resistance training. SAID principle (Specific Adaptation to Imposed Demands)
The frequency, duration/time and intensity of training undertaken – the greater the frequency, duration and intensity of training, the more pronounced the adaptations. However we must still consider the factors of overtraining and diminishing returns
The individual’s capacities and hereditary factors (genetic makeup or potential) – such as VO2 max and muscle-fibre type distribution (fast-twitch vs slow-twitch)

How long does training take before we expect to see chronic adaptations?

*Aerobic Training*	*Anaerobic Training*	*Resistance Training*
Minimum period for adaptation to occur is 6 weeks, although they are more evident after 12 weeks Developed through continuous, fartlek, long-interval and also HIIT training. Adaptations include an increased ability of the athlete to produce ATP aerobically through an improved economy	Minimum period for adaptations to occur with anaerobic training is 6 weeks Greatest adaptations occur in the muscular system, however changes also occur in the cardiovascular system Adaptation to anaerobic training are designed to bring about increased muscle size (hypertrophy), enabling greater force production, power output, strength and speed. Further adaptations include improved anaerobic capacity and tolerance to metabolic by-products	Neural adaptations have a substantial impact in the first 8-10 weeks of resistance training, After about 10 weeks, muscular hypertrophy is the predominant factor contributing to increased strength Developed through resistance training

TASK 2 – CHRONIC ADAPTATIONS TO AEROBIC TRAINING

With reference to the content notes, please answer the following questions:

With reference to the notes, summarise the aerobic chronic adaptations of the cardiovascular system.

CARDIOVASCULAR Adaptations to Aerobic Training
Adaptation		Explanation of how adaptation affects performance:
Increased Left Ventricle Size & Volume		Aerobic training results in the enlargement of the heart muscle (cardiac hypertrophy) For endurance athletes, an increase in the size and volume of the left ventricles significantly increases the stroke volume and cardiac output at maximal intensities, allowing a greater volume of blood to be ejected from the heart, thus providing more oxygen for the athlete to use
Increased Stroke Volume of the Heart		The increased capacity and size of the left ventricle together with greater blood volume and increased venous return contribute to a significant increase in the heart’s stroke volume after aerobic training As greater stroke volume allows more oxygen to be delivered to the working muscles, this improves the athlete’s ability to use more oxygen and thus improving their ability to use more oxygen and thus improving their ability to resynthesise ATP aerobically, This allows work at higher intensities for longer, with fewer fatiguing, producing an improved overall performance
Increased Capillarization of the Heart Muscle		Increase in the capillary density and blood flow to skeletal or cardiac muscle as a result of aerobic training The increased supply of blood and oxygen allows the heart to beat more strongly and efficiently during both exercise and rest
Decreased Resting Heart Rate		An athlete’s HR is a good indicator of their aerobic fitness. - Elite endurance athletes can have a resting heart rate as low as 35 bpm compared to an average resting HR of around 70bpm Amount of oxygen required at rest (approx 5L / min of blood does not change as a result of their training status. So as a result of greater stroke volume (another chronic adaptation), the left ventricle is pumping out with each beat, meaning that it is only required to contract less frequently to meet these demands at rest
Decreased Heart Rate During Submaximal Workloads		Trained aerobic athletes have lower HR when working at submaximal workloads compared untrained individuals As a result of higher stroke volume, more blood is pumped with each heartbeat, therefore the heart does not need to work as hard to supply the required blood flow and oxygen The heart also works more efficiently which results in a slower increase in HR during exercise and a faster attainment of steady state
Faster Recovery Heart Rate		Trained athlete’s HR will return to pre-exercise levels (resting HR) much quicker than that of untrained individuals. This occurs after both maximal and submaximal exercise A greater efficiency of the CV system enables this. The quicker the HR recovery, the more aerobically fit is the individual
Increased Cardiac Output During Maximal Exercise		While cardiac output remains unchanged at rest and during submaximal exercise, it does increase during maximal workloads (up to 25-30L/min) in trained individuals This is a result of the increase in stroke volume, because there is minimal increases in max HR (there is a limit to how fast your heart can beat)
Decreased Blood Pressure		A by-product of aerobic training is lower blood pressure, especially among people who suffer from hypertension Both the systolic and diastolic BP levels during rest and exercise will lower to help reduce resistance to blood flow and reduce strain on the heart (thereby decreasing the risk of heart attacks and other cardiovascular conditions)
Increased Capillarization of Skeletal Muscles		Greater capillary supply means increased blood flow, which in turn allows for greater supply of oxygen and nutrients to the muscles, and improved removal of by-products. The more capillaries that surround each muscle fibre, the more diffusion of oxygen can occur between the blood vessel and the skeletal muscle to maximise the rate of oxygen consumption by the muscles.
Increased Blood Volume		Regular and sustained aerobic training may lead to a 25% increase in total blood volume. This results in more red blood cells and the haemoglobin content (oxygen carrying capacity of the blood) Blood plasma may also increase significantly, resulting in an increased ratio of plasma in the cells which reduces the viscosity of the blood to allow it to flow more smoothly through the blood vessels

With reference to the notes, summarise the aerobic chronic adaptations of the respiratory system.

RESPIRATORY Adaptations to Aerobic Training
Adaptation		Explanation of how adaptation affects performance:
Increased Tidal Volume		Aerobic training will increase the strength and endurance of the respiratory muscles, allowing the individual to inhale and exhale more air. This results in a greater amount of air inspired and expired by the lungs per breath (same concept as improved stroke volume for CV system) This provides a greater amount of oxygen available to be diffused into the alveoli capillaries for transportation through the cardio-respiratory systems
Decreased Resting & Submaximal Respiratory Frequency		With an improved pulmonary efficiency and increase in the ability to extract oxygen from the alveoli, the number of times and athlete is required to breathe in and out per minute is lower at rest and during submaximal levels (same concept as lower resting HR for CV system)
Increased Pulmonary Ventilation during Maximal Exercise		Aerobic training results in more efficient and improved pulmonary ventilation (minute ventilation). At rest and during submaximal exercise, ventilation may decrease due to improved oxygen extraction However during maximal workloads, ventilation will increase as a result of a greater tidal volume and respiratory frequency (same concept as higher cardiac output for CV system)
Increased Pulmonary Diffusion		Aerobic training results in an increase in the surface area of the alveoli, which increases the pulmonary diffusion (improved oxygen and carbon dioxide exchange between the alveoli and the capillaries) This means more oxygen is extracted from the alveoli and more carbon dioxide is being removed from the capillaries

With reference to the notes, summarise the aerobic chronic adaptations of the muscular system.

MUSCULAR Adaptations to Aerobic Training
Adaptation		Explanation of how adaptation affects performance:
Increased Mitochondria & Myoglobin		Aerobic training enhances the ability ot extract oxygen into the muscles and use it to resynthesise ATP for energy and muscular contractions. Myoglobin and mitochondria both play key roles in working together to utilise the oxygen for ATP resynthesis. Mitochondria are the sites where aerobic resynthesis of ATP occurs Myoglobin are proteins in the muscle that transports oxygen between the bloodstream and the mitochondria Increased size and number of mitochondria – allows for the greater oxidation of fuels to produce ATP aerobically (the more sites available to produce energy, the more energy can be produced) Increased myoglobin stores - improves the ability of the muscles to extract oxygen and deliver it to mitochondria for energy production
Increased a-VO2 Difference		Trained aerobic athletes can extract more oxygen from their bloodstream into their muscles during both submaximal and maximal exercise. A greater a-VO2 difference enables more oxygen availability at the muscles for energy production.
Increased Muscular Fuel Stores & Oxidative Enzymes		Aerobic training increases the storage of glycogen and triglycerides (fuel for energy resynthesis) at the muscle, making energy production more readily available. Oxidative enzymes (responsible for metabolising these fuel stores for ATP) are also increased which means that there is less reliance on the anaerobic glycolysis system (allowing us to work aerobically with no fatiguing by-products) until higher intensities.
Increased Oxidation of Glucose & Triglycerides		The muscular adaptations in the muscle fibres allow for an improved ability of the aerobic system to metabolise glucose and triglycerides at any given exercise intensity. This means that a trained athlete has to rely less on glycogen (preferred fuel source), thereby ‘sparing’ their glycogen stores. Glycogen sparing allows the athlete to sustain a higher level of intensity, maintaining a faster pace, which results in an improved aerobic performance.
Adaptation of Muscle Fibre Type		Aerobic training has shown to improve the ability to recruit type IIb (fast twitch fibres) more in a manner that represents the more oxidative type IIa (fast twitch fibres). Some evidence also shows that fast twitch fibres can take on the characteristics of slow twitch fibre types as a result of endurance training, therefore improving aerobic performance. * Type I (slow twitch): oxidative fibres* * Type IIa (fast twitch): oxidative fibres* * Type IIb (fast twitch): glycolytic fibres*

CHRONIC ADAPTATIONS TO AEROBIC TRAINING: SUMMARY

CARDIOVASCULAR

RESPIRATORY

MUSCULAR

↑ left ventricle size and volume
↑ capillarisation of the heart muscle
↑ stroke volume of the heart
↓ resting heart rate
↓ heart rate during submaximal exercise
Faster recovery heart rate
↑ cardiac output during maximal exercise
↓ blood pressure
↑ capillarisation of skeletal muscle
↑ blood volume

↑ pulmonary ventilation during maximal exercise
↑ tidal volume
↓ resting and submaximal respiratory frequency
↑ pulmonary diffusion

↑ mitochondria and myoglobin
↑ arteriovenous oxygen difference (A-VO2-difference)
↑ muscular fuel stores and oxidative enzymes
↑ oxidation of glucose and triglycerides
Adaptation of muscle fibre type

↑ maximum oxygen uptake (VO2 max)

↑ lactate inflection point (LIP)

With reference to the notes, summarise the aerobic chronic adaptations of the combined systems.

COMBINED Adaptations to Aerobic Training
Adaptation		Explanation of how adaptation affects performance:
Increased Maximum Oxygen Uptake (VO₂ max)		Aerobic training results in a 5-30% increase in VO2 max during maximal exercise. This comes about through adaptations such as increases in cardiac output, red blood cell cell count, a-VO2 difference, muscle capillarization, greater oxygen extraction and utilisation (a combination of chronic adaptations from the cardiovascular, respiratory and muscular body systems)
Increased Lactate Inflection Point (LIP)

TASK 3 – CHRONIC ADAPTATIONS TO ANAEROBIC TRAINING

With reference to the content notes, please answer the following questions:

With reference to the notes, summarise the anaerobic chronic adaptations.

CHRONIC ADAPTATIONS TO ANAEROBIC TRAINING
Adaptation		Explanation of how adaptation affects performance:
Muscular Hypertrophy		Anaerobic training can lead to significant enlargement of muscle fibres (mainly type IIa and IIb fast twitch fibres), resulting in muscular hypertrophy. Muscular hypertrophy occurs as a result of an increased size and number of myofibrils per muscle fibre. This leads to increased levels of strength. Muscular hypertrophy is more pronounced in males than females due to higher levels of testosterone.
Increased Muscular Stores	of ATP, ATPase, creatine kinase enzymes & PC	Muscular hypertrophy is accompanied by increased muscular stores of ATP and creatine phosphate (CP) – which in turn increases the capacity of the ATP-PC system for high-intensity activities. There is also an increase in ATPase (enzymes required to break down and resynthesise ATP) and creatine kinase (helps initiate the breakdown of CP) – which both provide the energy to resynthesize ATP at a fast rate. Together they help speed, strength and power athletes by increasing the capacity of the ATP-PC system through greater energy release and faster restoration of ATP.
Increased Glycolytic Capacity		Enhanced muscular storage of glycogen and increased levels of glycolytic enzymes are adaptations of anaerobic training that increases the capacity of the anaerobic glycolysis system to produce energy.
Increased Ability to Recruit More Motor Units		The ability of the nerve axons to innervate their corresponding muscle fibre increases as a result of anaerobic training. This means that a greater number of motor units can be recruited, allowing for more strength and power that can be produced by the muscle.
Increased Lactate Tolerance		Working anaerobically means that an athlete is working above LIP, therefore producing lactate at a faster rate than it can be removed. With anaerobic training, the body learns to tolerate the increased levels of lactic acid by increasing the buffering capacity (ability of muscle cell to resist changes in pH acidity) which improves the ability to neutralise the acid that accumulates from the production of H+. * Note that this does not mean that lactate is removed – it is still present and simply being* buffered/tolerated Increased lactate tolerance prevents the onset of fatigue when the athlete is generating ATP anaerobically (at a faster rate, allowing them to work at a higher intensity).
Cardiac Hypertrophy		Anaerobic training results in the hypertrophy (enlargement) of the heart muscle itself. Rather than increasing the size of the ventricles (like aerobic training), anaerobic training increases the thickness of the ventricular walls. While little or no change in stroke volume occurs here, a more forceful contraction of the heart leads to a more forceful ejection of blood. Uniquely, this tends to benefit anaerobic more than aerobic performance

TASK 4 – CHRONIC ADAPTATIONS TO RESISTANCE TRAINING

With reference to the content notes, please answer the following questions:

With reference to the notes, summarise the resistance training chronic adaptations.

NEUROMUSCULAR Adaptations to Resistance Training
Adaptation		Explanation of how adaptation affects performance:
Increase in Muscle Size (Hypertrophy) and Change in Muscle Structure		Resistance training increases the strength and size of a muscle. This occurs through increases in the cross-sectional area of a muscle (hypertrophy and also increases in the number of muscle fibres (hyperplasia) Greater muscle size allows for greater force production and strength
Muscle Fibre Type Adaptation		Muscle fibre type adaptations are based upon the specificity of the training program (ie. strength, power, endurance, hypertrophy) Type II fast twitch fibres increase in size more than type 1 slow twitch fibres - which explains muscular hypertrophy as a result of resistance training
Increased Synchronization of Motor Units		Motor units are not recruited at the same time. The size principle states that motor units are ‘recruited in order of their size from smallest to largest’ Resistance training makes a number of different motor units able to fire at the same time, and allow for an improved ability to recruit larger motor units - which stimulates the larger muscle fibres to create a more powerful muscular contraction with greater force application
Increased Firing Rate (Rate Coding) of Motor Units		Rate coding/firing rate is the frequency of impulses sent to a muscle (to innervate and recruit the muscle fibres) An increase in rate coding or firing rate increases the rate of force development (how quickly a muscle can contract maximally), rather than an increase in force. This is beneficial for rapid movements where maximal force is required in a very short period of time (speed & power).
Reduction in Inhibitory Signals		Inhibitory mechanisms exist in the neuromuscular system to provide an important protective reflex that limits an excessive generation of force within a muscle.This protective reflex prevents the muscle from exerting a force greater than they can tolerate. Resistance training will gradually override this reflex and reduce the inhibitory mechanisms to allow for greater force production. By reducing the protective reflex, it allows more force to be produced within a muscle group.