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Chronic Adaptations to Training
Transcript of Chronic Adaptations to Training
Are specific to the training undertaken and the system where the change is occurring
Occurs in the cardiovascular, respiratory and muscular systems
Lead to improved performance in an athlete What are chronic adaptations? These adaptations improve the efficiency of the aerobic energy system to provide energy to the working muscles by increasing the body's ability to take up, transport and use more oxygen. Physiological changes as a result of aerobic training Cardiovascular adaptations to aerobic training - Increased Stroke Volume
- Decrease in resting HR Increased size and volume of left ventricular cavity If cardiac output is unchanged but HR decreases, there must be an increase in SV. The increase can be attributed to:
increase left ventricle volume and mass
reduced cardiac and arterial stiffness
increased diastolic filling time
increased cardiac contractility Three friends went on a fishing trip – a weight lifter, a triathlete and an accountant. Unfortunately their boat capsized and they perished. When their bodies were recovered autopsies were conducted and their hearts compared: In order from left to right the hearts belonged to: A. triathlete : weight lifter : accountant
B. accountant : weight lifter : triathlete
C. triathlete : accountant : weight lifter
D. weight lifter : accountant : triathlete Answer: D weight lifter : accountant : triathlete An increase in the capillaries that feed the heart This allows for improved blood flow to the heart, delivering more oxygen to the heart muscle to meet the energy demands of the myocardium (heart muscle).
- Blood flow to the heart muscle decreases slightly at rest and during submaximal exercise.
- Myocardium oxygen consumption decreases with aerobic training through increased SV and decreased HR. BLOOD! -Increases both the plasma volume and the red blood cell volume of the blood therefore increasing the overall blood volume.
- Increases in blood plasma assist in increasing SV, due to the increase in the volume of blood that can fill the heart during diastole (relaxation phase of the heart beat). Also assist in regulation of body temperature. - The total amount of haemoglobin in the blood increases with aerobic training. Haemoglobin is important for the transport of oxygen from the lungs to working muscles.
- Increaes in blood volume are associated with greater amounts of haemoglobin, but the haemoglobin concentration does not increase.
- Blood lactate concentration has been shown to decrease. Accompanying an overall decrease in blood lactate is the ability for endurance-trained athletes to extend exercise levels before OBLA (onset of blood lactate accumulation) Respiratory Adaptations - Aerobic training increases pulmonary function, which results in the increases in lung volumes.
- Total lung volume capacity is the amount of air in the lungs at the end of a maximal inspiration in one breath.
- Vittal capacity is the volume of air that can be forcefully expired after maximal insiration.
- Diffusion of oxygen across the alveolar-capillary membrane and of carbon dioxide across the tissue-capillary membrane is greater in trained subjects.
- The increase in diffusion is seen at rest and during submaximal and maximal exercise intensities. - During exercise at a submaximall level, endurance-trained athletes have lower ventilation rates compared to untrained athletes.
- Ventilation at max intensity will, however, increase following aerobic training. An increase in tidal volume and breathing frequency leads to the increase in maximum ventilation.
- Ventilatory efficiency occurs as a result of training. Less oxygen is delivered to the muscles responsible for breathing.
- Oxygen consumption is the amount of oxygen taken up and used by the body. Max O2 consumption has been shown to increase with aerobic training. Muscular Adaptations Arteriovenous Oxygen Difference (a-vO2 diff) Aerobic Training leads to an increase in the amount of oxygen extracted from the blood by the muscles, or a-vO2 diff. Myoglobin and Mitochondria - The myoglobin content in slow-twitch fibres increase as a result of aerobic training.
- Myoblogin assists in delivering oxygen across the cell membrane to the mitochondria, where it is used in the process of energy production.
- Increased myoglobin levels increase the available oxygen for aerobic respiration.
- Mitochondria increase in size, number and surface area, enhancing the capacity of the muscle to produce ATP aerobically. Oxidation of Glycogen - Aerobic training increases the ability of the skeletal muscle to oxidise glyocogen.
- The adaptations that cause an increase in the energy-generating capacity of the muscle are:
an increase in number, size and surface area of mitochondria
an increase in enzyme activity and concentration
an increase in muscle glyogen stores Oxidation of Fats - Changes within the muscle significantly improve the function of the muscle during sustained aerobic exercise.
- One effect of these changes is the increased oxidation (breakdown of fats or glycogen to CO2 and H2O in the presence of O2) of free fatty acids.
- During submaximal exercise, endurance-trained athletes are able to oxidise fatty acids more readily.
- Fat is a major food source for muscular contraction during exercise, and and increased ability to oxidise fat is advantageous in endurance activities. A middle distance runner undertakes 12 months of aerobic training in an effort to break into the senior athletics team as a 5,000m runner. Compared to 12 months ago, he would now have : A. Increased oxidative enzymes at leg muscles
B. Increased energy usage at each stage of the race
C. Decreased oxygen phosphorylase at slow twitch fibres
D. Decreased reliance upon the anaerobic glycolysis system A. Increased oxidative enzymes at leg muscles What happens to the arteriovenous oxygen difference (a-vO2 diff) at maximal intensities in response to 9 months of Fartlek training? Answer: It increases Discuss two factors that contribute to the response you have identified in above. Increased capillarisation of the muscle fibres (essentially slow twitch) which leads to an increase in the diffusion of oxygen, carbon dioxide and other metabolic by-products.
Increased diffusion and blood distribution to the working muscles which increases oxygen supply/concentration to working muscles
Increased capacity of the muscles to extract and process oxygen via increased mitochondria and oxidative enzymes, leads to an increase in the a-vO2 diff Adaptations to aerobic training Chronic Adaptations to anaerobic training Muscular adaptations Cardiovascular adaptations Anaerobic training will result in insignificant changes to the cardiovascular and respiratory systems but major long term changes to fast twitch fibres Anaerobic training will result in insignificant changes to the cardiovascular and respiratory systems but major long term changes to fast twitch fibres The major adaptation of the cardiovascular system is an enlargement of the cardiac (heart) muscles. In comparison to the aerobic adaptations of the cardiovascular system the volume of the champers do not change however the thickness of the ventricle walls increase allowing the heart to contract more forcefully.