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TRAINING ADAPTATIONS

TRAINING ADAPTATIONS . Lect. II. Lower heart rate during sub-maximal workloads :. Mainly a result of increased stroke volume.

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TRAINING ADAPTATIONS

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  1. TRAINING ADAPTATIONS Lect. II

  2. Lower heart rate during sub-maximal workloads: • Mainly a result of increased stroke volume. • The heart works more efficiently - (More blood is pumped with each beat, andtherefore the heart doesn’t have to work as hard to supply the required blood flow andoxygen supply) • Slower increase in heart rate during exercise and a lower and faster attainment of steady state during exercise

  3. Improved heart-rate recovery rates: • Heart rate of a trained athlete will return topre-exercise levels (resting rate) in a muchshorter time than that of an untrainedindividual.

  4. Increased cardiac output at maximum workloads • Cardiac output – unchanged at rest and evenduring sub-maximal exercise regardless oftraining status. • Does increase during maximalexercise. • Maximal exercise – may increase to values of: • · 20-22 litres per minute for untrainedmale • · 15-16 litres per minute for untrained • · 30 litres per minute or more – highly trained athletes females

  5. Lower blood pressure: • May lower blood pressure, especially among people who suffer from hypertension(high blood pressure) • Systolic and diastolic pressure levels may decrease during both rest and exercise • Helps to reduce resistance to blood flow and reduces strain on the heart, therebydecreasing the risk of heart attack and other cardiovascular conditions

  6. The arteriovenous oxygen difference, or a-vO2 diff, is the difference in the oxygen content of the blood between the arterial blood and the venous blood. It is an indication of how much oxygen is removed from the blood in capillaries as the blood circulates in the body.

  7. Increased arterio-venous oxygen difference (a-VO2 diff): • Trained individuals are able to absorb more oxygen from their bloodstream into theirmuscles during exercise performance compared to untrained subjects. • This is due to: • · Increased muscle myoglobin stores • · Increased number and size of mitochondria within their muscles

  8. As a result of this, the concentration of oxygen within the venous blood is lower • Subsequently the arterio-venous oxygen difference is increased during both sub-maxand maximal exercise • Therefore, and increased arterio-venous oxygen difference (a-VO2 diff) indicates agreater uptake of oxygen by the muscles with trained individuals

  9. Increased blood volume and haemoglobin levels: • Total blood volume may rise by up to 25% (from 5.25L to 6.6L) for an average adultmale with regular and sustained aerobic training. • Red blood cells may increase in number and the haemoglobin content and oxygencarryingcapacity of the blood may also rise.

  10. Increased capillarisation of skeletal muscle: The average number of capillaries supplying each muscle fibers is: • · 5.9 for trained athletes • · 4.4 for untrained athletes

  11. Changes to blood cholesterol, triglycerides, low- and high-density lipoprotein levels: • Results may include a decrease in blood cholesterol levels, triglycerides and low densitylipoprotein (LDL). • These substances are associated withthe development of coronary heartdisease. • Aerobic training increases the ratio ofhigh-density lipo-protein (HDL) tolow-density lipoprotein. • High-density lipoprotein is thought toprovide a coronary protective effect,lessening the risk of developingcoronary heart disease.

  12. SUMMARY CV adaptations

  13. Respiratory Adaptations

  14. B) RESPIRATORY ADAPTATIONS to aerobic training • More efficient and improved lung ventilation • At rest and during sub-maximal exercise, ventilation may be reduced due to improvedoxygen extraction • However, during maximal workloads, ventilation is increased because of increasedtidal volume (amount of air breathed in and out in one breath) and respiratoryfrequency (the number of breaths taken per minute). • Pulmonary diffusion (the ability of the blood to extract oxygen from the alveoli) is alsoenhanced.

  15. Increased maximum oxygen uptake (VO2 max) • Increase in the maximum oxygen uptake (VO2 max) during maximal exercise • Improvement can be between 5–30% following a regular and sustained trainingprogram

  16. This occurs because of adaptations such · Increased cardiac output • · Increased red blood cell numbers • · Increased a-VO2 difference • · Increased muscle capillarisation • · Greater oxygen extraction by the muscles as:

  17. Increased anaerobic or lactate threshold • As a result of the adaptations that improve oxygen delivery and utilisation in themuscles, a higher lactate threshold (the point at which oxygen supply cannot keep upwith oxygen demand) is developed.

  18. Advantage: • The anaerobic glycolysis (lactic acid) system is not utilised as much until higherexercise intensities are reached. • Consequently, lactic acid and hydrogen ion accumulation will be delayed until thesehigher work-load intensities are attained • The athlete can “work harder and for longer periods”

  19. Muscle Tissue Adaptations to Aerobic (Endurance) Training: • Chronic aerobic training adaptations within muscular tissue are best produced throughcontinuous training or high-repetition resistance training • The following tissue-level changes can be observed within skeletal muscles followingextensive endurance training:

  20. Increased oxygen utilisation: • Aerobic training enhances the body’s ability to attract oxygen into the muscle cells and • then utilise it to produce adenosine triphosphate (ATP) for musclecontraction • This process occurs in the following ways: • · Increased size and number of mitochondria –

  21. Mitochondria are the site of ATP synthesis and where glycogen and triglyceridestores are oxidised (Greater oxidisation of fuels to produce ATP) • · Increased myoglobin stores – Myoglobin is the substance in the muscle cell thatattracts oxygen from the bloodstream into the muscle. (Increase ability to extractoxygen)

  22. Increased muscular fuel stores: • Increase in the muscular storage of glycogen, free fatty acids and triglycerides, alongwith the oxidative enzymes required to metabolise these fuel stores and produce ATP.

  23. Increased oxidation of glucose and fats: • The muscular adaptations result in an increase in the capacity of muscle fibers tooxidate both glucose and fats • The capacity of the aerobic system to metabolise these fuels is increased • Increased oxidation of fats as a fuel source; due to: • · Increased storage of triglycerides and free fatty acids • · Increased levels of enzymes associated with fat metabolism

  24. Means that: • At any given exercise intensity, a trained individual has to rely less on glycogen,thereby “sparing” glycogen stores (Glycogen sparing) • Therefore delaying the time to exhaustion due to glycogen depletion.

  25. Decreased utilisation of the anaerobic glycolysis (lactic acid) system: • The enhanced capacity of the muscles to aerobically metabolise glucose and fats andother muscular level adaptations also means that there is less reliance upon theanaerobic glycolysis system to produce energy for ATP resynthesis until higherexercise intensities are reached. • · Allows athletes to work at higher intensities without exceeding lactate threshold. • OR • · Aerobic training results in an increase in the lactate threshold

  26. Eg. An athlete must run at a faster pace in order to accumulate the same amount of blood lactic acid as before training

  27. Muscle- fiber type adaptation: • Some research has shown evidence that skeletal muscle switches fiber types from fast twitch to slow twitch as a result of endurance training. • Skeletal muscle fibers are classified into three types: • Type 1 – Slow-twitch oxidative fibers: • · Contain large amounts of myoglobin, and large numbers of mitochondria and blood capillaries.

  28. Red • · Split ATP at a slow rate • · Slow contraction velocity • · Very resistant to fatigue • · High capacity to generate ATP by oxidative metabolic processes.

  29. Type 2A – Fast-twitch oxidative fibers: • · Contain an extremely large amount of myoglobin, and huge numbers of mitochondria and blood capillaries. • · Red • · Very high capacity for generating ATP by oxidative metabolic processes • · Split ATP at a very rapid rate • · Fast contraction velocity • · Resistant to fatigue

  30. Type 2B – Fast-twitch glycolytic fibres: • · Contain low myoglobin content, relatively few mitochondria and blood capillaries, and large amounts of glycogen • · White • · Geared to generate ATP by anaerobic metabolic processes • · Fatigue easily • · Split ATP at a fast rate • · Fast contraction velocity • Individual muscles are a mixture of the three types of muscle fibers, but their proportions vary depending on the action of the muscle and the genetic make-up of the individual

  31. Summary of muscle tissue adaptations to aerobic (endurance) training:

  32. Thank you

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