Section 06: Exercise Training to Improve Performance Chapter 21 Training for Anaerobic and Aerobic Power Chapter 22 Muscular Strength: Training Muscles to Become Stronger Chapter 23 Special Aids to Exercise Training and Performance HPHE 6710 Exercise Physiology II Dr. Cheatham Chapter 21 Training for Anaerobic and Aerobic Power 1
Chapter Objectives Understand the concepts of overload, specificity, reversibility Understand the metabolic adaptations associated with anaerobic training Understand the metabolic adaptations associated with aerobic training Understand the cardiovascular and pulmonary adaptations to aerobic training Training Principles 2
Training Principles Overload Principle Regular application of a specific exercise overload enhances physiologic function to induce a training response Overload may be achieved using a combination of: Intensity Duration Frequency Training Principles Specificity Principle Adaptations in metabolic and physiologic functions that depend upon the type and mode of overload imposed. Specific exercise elicits specific adaptations to create specific training effects 3
Training Principles Specificity Principle (cont d) Specificity of VO 2max Training Principles Specificity Principle (cont d) Specificity of local changes Overloading specific muscle groups with endurance training enhances exercise performance and aerobic power by facilitating oxygen transport AND use at the local level of the trained muscle Example: Vastus lateralis muscle of well trained cyclists has greater oxidative capacity than that of endurance runners» Greater regional blood flow in active tissues Increases microcirculation More effective distribution of Q Combined effects of both factors 4
Training Principles Training Principles Specificity Principle (cont d) Individual differences principle Many factors contribute to individual variation in the training response A person s relative fitness values at the start of training (i.e. initial value) Genetic factors 5
Training Principles Training Principles Reversibility Principle Loss of physiologic and performance training adaptations occurs rapidly when a person terminates participation in regular exercise 6
Training Principles Training Principles 7
Physiologic Consequences of Training Quick Metabolism Review 8
Quick Metabolism Review Quick Metabolism Review 9
Anaerobic System Changes with Training Increases in resting muscle levels of ATP PCr Free creatine Glycogen Glycolytic enzymes Resulting in increased capacity to generate blood lactate Anaerobic System Changes with Training 10
Anaerobic System Changes with Training 11
Metabolic Adaptations Metabolic Machinery Number and size of mitochondria Aerobic system enzymes Nearly two fold increase within 5 to 10 days Increased mitochondrial capacity to generate ATP aerobically Metabolic Machinery Number and size of mitochondria Example: Exercise at the LT for 30 min/day, 5 days/week, 6 weeks increased mitochondrial density by 40%. 12
Number and Size of Mitochondria Metabolic Machinery (cont d) Aerobic system enzymes Nearly two fold increase within 5 to 10 days 94% 117% 13
Aerobic System Enzymes Capillary Density Increase perfusion of active muscle with blood Greater delivery of O 2 and points for diffusion Aerobic training increases the number of overall capillaries and the capillary to fiber ratio 7% higher # of capillaries 38% higher c to f ratio 14
Capillary Density 29% 26% Capillary Density 30 15
Capillary Density 31 Metabolic Adaptations (cont d) Fat Metabolism Endurance training increases the oxidation of fatty acids for energy during submaximal exercise Increases in training induced lipolysis occur due to: Greater blood flow within trained muscle More fat mobilizing and fat metabolizing enzymes Enhances muscle mitochondrial respiratory capacity Decreases catecholamine release for the same absolute power output Why is an increase in fat metabolism beneficial for endurance performance? 16
Fat Metabolism 17
Metabolic Adaptations (cont d) Carbohydrate Metabolism Trained muscle exhibits enhanced capacity to oxidize carbohydrate during maximal exercise Muscle Fiber Type and Size Aerobic training elicits metabolic adaptations in each type of muscle fiber Basic fiber type probably doesn t change much Selective hypertrophy occurs in the different muscle fiber types with specific overload training 18
Metabolic Adaptations (cont d) Myoglobin Slow twitch fibers contain relatively large quantities of myoglobin In animals, amount of myoglobin relates to their physical activity Unclear in humans whether regular exercise exerts any meaningful effect on myoglobin levels 19
Cardiovascular Adaptations Cardiovascular Adaptation (cont d) Cardiac Hypertrophy: The Athlete s Heart Long term aerobic training generally increases the heart s mass and volume with greater left ventricular enddiastolic volumes noted during rest and exercise. Eccentric hypertrophy: Size of the left ventricular cavity Concentric hypertrophy: Modest thickening of the walls Increases sensitivity to calcium 20
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Cardiovascular Adaptations (cont d) Plasma Volume A 12 to 20% increase in PV occurs after 3 to 6 aerobic training sessions Measurable change within 24 hours Increases synthesis and retention of albumin Hemoglobin mass and blood volume averaged 35% higher in endurance athletes compared to untrained subjects. 22
Role of albumin in controlling plasma volume Interstitial Space Blood Vessel CON 0.4% EX 12.3% EXSAL 13.3% 30 min REC 150 min REC 24 hrs REC 23
30 min REC 150 min REC 24 hrs REC Cardiovascular Adaptations (cont d) Heart Rate Resting and submaximal exercise HR s are decreased Increased vagal tone Decrease in intrinsic firing rate of SA node Relationship with SV» Chicken or the egg 24
Cardiovascular Adaptations (cont d) Stroke Volume Increased at rest, submaximal exercise, and maximal exercise Increased leftventricular volume» PV and mass Reduced cardiac and arterial stiffness Increased diastolic filling time Improved cardiac contractility 25
Cardiovascular Adaptations (cont d) Cardiac Output Most significant adaptation Maximal cardiac output increases with endurance training Submaximal cardiac output may be the same or slightly decreased at a given submaximal exercise intensity If it is lower, what does that mean (i.e. what other variable must be higher?) Cardiovascular Adaptations (cont d) Oxygen Extraction (a vo 2 diff) Increases the quantity of oxygen extracted from circulating blood. 26
Cardiovascular Adaptations (cont d) Blood Flow Distribution Submaximal Exercise Lower Q but greater and unchanged or slightly lower muscle blood flow Increase in blood flow to muscles with high percentage of Type I fibers at the expense of blood flow to muscles with high percentage of Type II fibers» Rapid training induced changes in the vasoactive properties of large arteries and local resistance vessels» Changes that enhance oxidative capacity Cardiovascular Adaptations (cont d) Blood Flow Distribution (cont d) Maximal Exercise Increase in total blood flow with training» Larger maximal Q» Greater reductions in blood flow to non active areas» Enlargement of vascular cross sectional area Myocardial Blood Flow Increases Blood Pressure Decreases 27
Pulmonary Adaptations with Training Maximal exercise Increases ventilation (tidal volume and frequency) Submaximal exercise Reduces the ventilatory equivalent for oxygen Tidal volume increases and breathing frequency decreases 28
Pulmonary Adaptations (cont d) Training may benefit ventilatory endurance Reduces overall exercise energy demands because of less respiratory work Reduces lactate production by ventilatory muscles Enhances how ventilatory muscles metabolize circulating lactate as metabolic fuel Explain this 29
Blood Lactate Concentration 30