Training for Anaerobic and Aerobic Power PDF

Chapter 21 Training for Anaerobic and Aerobic Power Copyright © 2023 Wolters Kluwer Health | Lippincott Williams & Wilkins Chapter Objectives #1 Discuss and provide examples of the exercise training principles of overload, specificity, individual differences, and reversibility...

Chapter 21 Training for Anaerobic and Aerobic Power Copyright © 2023 Wolters Kluwer Health | Lippincott Williams & Wilkins Chapter Objectives #1 Discuss and provide examples of the exercise training principles of overload, specificity, individual differences, and reversibility Outline metabolic adaptations to anaerobic training and metabolic, cardiovascular, and pulmonary adaptations to aerobic training Describe the athlete’s heart and contrast structural and functional heart characteristics for an endurance athlete versus a resistance-trained athlete Describe how initial fitness level, genetics, and training frequency, duration, and intensity influence the aerobic training response Copyright © 2023 Wolters Kluwer All Rights Reserved Chapter Objectives #2 Discuss the rationale for heart rate to establish aerobic training intensity Discuss heart rate variability, how it is measured, and the context in which it is used Justify how the “rating of perceived exertion” establishes the aerobic activity intensity Give two advantages of training at the lactate threshold Contrast continuous and intermittent aerobic training and two advantages and disadvantages for each Copyright © 2023 Wolters Kluwer All Rights Reserved Chapter Objectives #3 Summarize three important factors to implement interval training exercise prescriptions Describe the most common overtraining syndrome, and summarize interacting factors contributing to overtraining in endurance athletes Summarize current physical activity guidelines before, during, and after pregnancy Copyright © 2023 Wolters Kluwer All Rights Reserved Classification of Physical Activity Based on Duration of All-out Effort Copyright © 2023 Wolters Kluwer All Rights Reserved Exercise Training Principles Stimulating structural and functional adaptations to improve performance in specific physical tasks remains a major objective of exercise training Basic approach to physiologic conditioning applies similarly to men and women within a broad age range Both respond and adapt to training in essentially similar ways Copyright © 2023 Wolters Kluwer All Rights Reserved Overload Principle Appropriate overload requires either manipulating training frequency, intensity, and duration, or combining these factors. Individualized and progressive overload applies to athletes, sedentary persons, disabled persons, and even cardiac patients. Achieving health-related benefits of regular exercise requires lower effort intensity (but greater volume) than required to improve aerobic capacity. Copyright © 2023 Wolters Kluwer All Rights Reserved Specificity Principle Exercise training specificity refers to adaptations in metabolic and physiologic functions that depend upon the type and mode of overload imposed. Most effective evaluation of sport-specific performance occurs when measurement most closely simulates the actual activity and/or uses the muscle mass and movement patterns sport requires. Specific exercise elicits specific adaptations to promote specific training effects that produce specific performance improvements, specific adaptations to imposed demands (SAIDs) principle. Copyright © 2023 Wolters Kluwer All Rights Reserved Maximum Oxygen Uptake Specificity When training for specific aerobic activities, overload must: – Engage appropriate muscles required by activity – Provide exercise at a level sufficient to stress cardiovascular system Little improvement is noted when measuring aerobic capacity with dissimilar exercise – Greatest improvement occurs when test exercise duplicates training exercise Copyright © 2023 Wolters Kluwer All Rights Reserved Aerobic Training Specificity Copyright © 2023 Wolters Kluwer All Rights Reserved Local Muscle–Induced Specificity Overloading specific muscles with endurance training enhances performance and aerobic power by facilitating O2 transport to and O2 use by trained muscles. Greater blood flow in active tissues results from: – More effective redistribution of cardiac output – Increased microcirculation – Combined effect of both factors Adaptations occur only in specifically trained muscles and become apparent in exercise that activates this musculature. Copyright © 2023 Wolters Kluwer All Rights Reserved Individual Differences Principle All individuals do not respond similarly to a given training stimulus. When a relatively homogenous group begins exercise training, one cannot expect each person to achieve same fitness improvements. Optimal training benefits occur when exercise programs focus on the participant’s individual needs and capacities. Copyright © 2023 Wolters Kluwer All Rights Reserved Reversibility Principle Detraining rapidly occurs when terminating a training program. Only 1 or 2 wk of detraining reduces both metabolic and exercise capacity. Many training improvements fully lost within several months. Even with highly trained athletes, beneficial effects of prior training remain transient and reversible. Most athletes begin reconditioning several months prior to competitive season, or maintain moderate level of off-season, sport-specific training to slow detraining effects. Copyright © 2023 Wolters Kluwer All Rights Reserved Anaerobic System Changes with Training Increased levels of anaerobic substrates Increased quantity and activity of key enzymes that control the anaerobic phase of glucose catabolism Increased capacity to generate and tolerate high blood lactate levels during all-out effort Increased levels of glycogen and glycolytic enzymes Improved motivation and tolerance to “pain” Copyright © 2023 Wolters Kluwer All Rights Reserved Increases in Skeletal Muscle Anaerobic Energy Metabolism with Sprint-Power Training Copyright © 2023 Wolters Kluwer All Rights Reserved How Training Impacts the Aerobic System Four categories of diverse physiologic and metabolic factors related to O2 transport and use: – Ventilation-aeration – Central blood flow – Active muscle metabolism – Peripheral blood flow With training, positive adaptations remain independent of race, gender, age, and health status Copyright © 2023 Wolters Kluwer All Rights Reserved Physiologic Factors that Limit VO2max and Aerobic Performance Copyright © 2023 Wolters Kluwer All Rights Reserved Metabolic Adaptations Aerobic training improves capacity for respiratory control in skeletal muscle. Endurance-trained skeletal muscle fibers contain larger and more numerous mitochondria than less active fibers. Twofold increase in aerobic system enzymes within 5 to 10 training days coincides with increased mitochondrial capacity to generate ATP aerobically. Copyright © 2023 Wolters Kluwer All Rights Reserved Lipid Metabolism Endurance training increases fatty acid oxidation during rest and submaximal exercise Four factors contribute to a heightened training- induced increased lipolysis: – Greater blood flow within trained muscle – More lipid-mobilizing and lipid-metabolizing enzymes – Enhanced muscle mitochondrial respiratory capacity – Decreased catecholamine release at the same absolute power output Copyright © 2023 Wolters Kluwer All Rights Reserved Aerobic Training Enhances Lipid Catabolism in Submaximal Exercise Copyright © 2023 Wolters Kluwer All Rights Reserved Carbohydrate Metabolism Trained muscle exhibits enhanced capacity to oxidize carbohydrate during maximal exercise Reduced carbohydrate as fuel and increased fatty acid combustion in submaximal exercise, results from three combined effects: – Decreased muscle glycogen use – Reduced glucose production – Reduced plasma-borne glucose use Copyright © 2023 Wolters Kluwer All Rights Reserved Muscle Fiber Type and Size Enhanced metabolic adaptations in each muscle fiber type All fibers maximize existing aerobic potential Endurance athletes have larger slow-twitch fibers than fast-twitch fibers in same muscle Slow-twitch fibers with high capacity to generate ATP aerobically contain large quantities of myoglobin Copyright © 2023 Wolters Kluwer All Rights Reserved Aerobic Training Increases Oxygen Delivery to Active Muscles Copyright © 2023 Wolters Kluwer All Rights Reserved Cardiac Hypertrophy: The “Athlete’s Heart” Long-term aerobic training increases heart’s mass and volume with greater left-ventricular end- diastolic volumes during rest and exercise. Cardiac enlargement characterized by increased left- ventricular cavity size or eccentric cardiac hypertrophy, and a modest wall thickening or concentric cardiac hypertrophy. Endurance athletes average 25% larger heart volume than sedentary counterparts. Training duration affects cardiac size and structure. Copyright © 2023 Wolters Kluwer All Rights Reserved Functional Versus Pathologic Cardiac Hypertrophy Disease induces considerable cardiac enlargement. Pathologic “hypertrophied” heart: enlarged, distended, functionally inadequate organ unable to deliver blood sufficient for resting requirements. Exercise training in the healthy imposes a temporary myocardial stress so rest periods provide for “recuperation.” “Athlete’s heart” does not represent dysfunctional organ. Rather, it demonstrates normal systolic and diastolic functions and superior functional capacity. Copyright © 2023 Wolters Kluwer All Rights Reserved Plasma Volume A 12 to 20% increase in plasma volume occurs after three to six aerobic training sessions without any increase in red blood cell mass. Plasma volume increase enhances circulatory reserve and increases end-diastolic volume, stroke volume, oxygen transport, VO2max, and temperature- regulating ability during physical activity. Expanded plasma volume returns to pretraining levels within 1 week following training. Hb mass and blood volume averaged 35% higher in endurance athletes than in untrained subjects. Copyright © 2023 Wolters Kluwer All Rights Reserved Heart Rate and Oxygen Uptake During Exercise in Endurance Athletes Copyright © 2023 Wolters Kluwer All Rights Reserved Heart Rate Variability Heart rate variability (HRV) represents the beat-to- beat variation in either heart rate or R–R interval duration. HRV as a clinical tool to evaluate cardiac autonomic changes in cardiovascular and other disease states. HRV is reduced in diabetes, smoking, obesity, stress, hypertension, multiple sclerosis, in patients recovering from myocardial infarction, end-stage renal disease, and congestive heart failure. Measured with 24-hr electrocardiographic recordings made while subjects perform usual activities of daily living. Copyright © 2023 Wolters Kluwer All Rights Reserved Stroke Volume Response During Upright Exercise for Endurance Athletes and Sedentary Students Copyright © 2023 Wolters Kluwer All Rights Reserved Cardiac Output and Oxygen Uptake During Upright Physical Activity Copyright © 2023 Wolters Kluwer All Rights Reserved a-vO2 Difference and Oxygen Uptake During Upright Exercise Copyright © 2023 Wolters Kluwer All Rights Reserved Blood Flow and Distribution In submaximal exercise, lower cardiac output with training: – Rapid training-induced changes in vasoactive properties of large arteries and local resistance vessels within skeletal and cardiac muscle – Muscle cell changes that enhance oxidative capacity In maximal exercise, larger maximal cardiac output with training: – Greater blood distribution to muscle from nonactive areas – Enlargement of cross-sectional areas of arteries and veins; 20% increase in capillarization/g muscle Copyright © 2023 Wolters Kluwer All Rights Reserved Myocardial Blood Flow Vascular modifications include: – Increase in cross-sectional area of proximal coronary arteries, possible arteriolar proliferation and longitudinal growth, recruitment of collateral vessels, and increased capillary density – Provides adequate perfusion for increased blood flow and energy demands Training increases coronary blood flow and capillary exchange capacity from: – Structural remodeling to improve vascularization – More effective control of vascular resistance and blood distribution within myocardium Copyright © 2023 Wolters Kluwer All Rights Reserved Blood Pressure Regular aerobic training reduces systolic and diastolic blood pressure during rest and submaximal exercise. Largest reduction occurs in systolic pressure, particularly in hypertensive subjects. Copyright © 2023 Wolters Kluwer All Rights Reserved Pulmonary Adaptations Maximal exercise VE increases from increased tidal volume and breathing rate as VO2max increases. Submaximal exercise reduces VE/VO2 and lowers % total exercise O2 cost attributable to breathing. Pulmonary adaptations enhances exercise endurance by: – Reducing fatigue of ventilatory musculature – Oxygen not used by respiratory musculature, becomes available to active locomotor muscles Training increases tidal volume and decreases breathing frequency, increasing O2 extraction from inspired air. Copyright © 2023 Wolters Kluwer All Rights Reserved Training May Benefit Ventilatory Endurance Training enhances ability for sustained, exceptionally high levels of submaximal VE Training increases inspiratory muscle capacity to generate force and sustain inspiratory pressure This benefits exercise performance by: – Reducing overall exercise energy demands because of less respiratory work – Reducing lactate production by ventilatory muscles during intense, prolonged exercise – Enhancing how ventilatory muscles metabolize circulating lactate as metabolic fuel Copyright © 2023 Wolters Kluwer All Rights Reserved Response for Pretraining and Posttraining Lactate Accumulation Copyright © 2023 Wolters Kluwer All Rights Reserved Four Additional Aerobic Training Adaptations Favorable body composition changes: Exercise only or combined with calorie restriction reduces body fat more than weight loss with dieting More efficient body heat transfer: larger plasma volumes elicit more responsive thermoregulatory mechanisms Performance changes: enhanced endurance performance accompanies physiologic adaptations with training Positive psychological benefits: creates important potential benefits on psychological state Copyright © 2023 Wolters Kluwer All Rights Reserved Summary of Training Adaptations Copyright © 2023 Wolters Kluwer All Rights Reserved Seven Factors Affecting Aerobic Training Responses 1. Initial aerobic fitness level 2. Training intensity 3. Training duration 4. Training volume 5. Training frequency 6. Training mode 7. Training progression Copyright © 2023 Wolters Kluwer All Rights Reserved Train at Rating of Perceived Exertion The rating of perceived exertion (RPE), a psychophysiologic scaling approach, allows a person to rate physical activity intensity. Exercise at higher levels of energy expenditure and physiologic strain produces higher RPE ratings. A simple “talk test” that asks whether comfortable speech is possible produces exercise intensities within accepted guidelines for exercise prescription for treadmill and cycle ergometer. Copyright © 2023 Wolters Kluwer All Rights Reserved Training Duration No duration threshold per workout exists for optimal aerobic improvement. If a threshold exists, it likely depends on interaction of four variables: Total work accomplished (volume), Exercise intensity, Training frequency, Initial fitness level. Shorter high-intensity interval training (HIIT) bouts discussed in a later section have improved many cardiorespiratory health markers including exercise performance. Copyright © 2023 Wolters Kluwer All Rights Reserved Training Volume Exercise volume generally includes gross energy expenditure expressed in total kcal or METs. Total energy expenditure of between 500 and 1000 METs per wk consistently associates with a lower rate of cardiovascular disease and premature mortality. About 150 min·wk−1 approximates 1000 kcal in moderate-intensity physical activity. Copyright © 2023 Wolters Kluwer All Rights Reserved Training Frequency More frequent training produces beneficial effects when training at lower intensity. Extra quantity of exercise represents considerable kcal expenditure with concomitant improvements in well-being and health. To produce weight loss with exercise, each session should last minimum 60 min at sufficient intensity to expend 300 kcal or more. Typical aerobic training programs take place 3 d·wk−1 with a single rest day separating workout days. Copyright © 2023 Wolters Kluwer All Rights Reserved Training Mode Bicycling, walking, running, rowing, swimming, in- line skating, rope skipping, bench-stepping, stair climbing, and simulated arm–leg climbing all provide excellent overload for the aerobic system. Based on specificity concept, magnitude of training improvement varies depending on training and testing mode. Copyright © 2023 Wolters Kluwer All Rights Reserved Training Progression Exercise progressions include increases in training intensity, duration, and frequency. Most individuals tolerate a 5- to 10-min session increase every 1 to 2 wk over the first 4- to 6-wk period. Gradually increasing and/or varying exercise intensity enhances the training response. Copyright © 2023 Wolters Kluwer All Rights Reserved Anaerobic Training: Intramuscular High- Energy Phosphates Engaging specific muscles in repeated 5- to 10-s maximum bursts of effort overloads the phosphagen pool’s energy transfer contribution. Use of brief, all-out exercise bursts interspersed with recovery represents a highly specific application of interval training to anaerobic conditioning. Physical activities to enhance ATP–PCr energy transfer capacity in a specific sport must engage muscles at movement speed and power output similar to performance of that sport. Copyright © 2023 Wolters Kluwer All Rights Reserved Anaerobic Training: Lactate-Generating Capacity To improve energy transfer capacity by the short- term lactic acid energy system, training must overload this anaerobic energy system. Blood lactate rises to near-peak levels with 1-min maximal exercise; repeat same exercise bout after 3- to 5-min recovery. Causes “lactate stacking,” producing higher blood lactate level than just one all-out effort. Must exercise specific muscle groups that require enhanced anaerobic function. Copyright © 2023 Wolters Kluwer All Rights Reserved Aerobic Training: Continuous Versus Intermittent Methods Factors in formulating aerobic training: – Cardiovascular overload must be intense enough to sufficiently overload stroke volume and cardiac output. – Cardiovascular overload must occur from activation of sport-specific muscle groups to enhance local circulation and muscle’s “metabolic machinery.” Brief bouts of repeated exercise and continuous, long-duration efforts enhance aerobic capacity, provided they reach sufficient intensity to overload aerobic system Interval, continuous, and fartlek represent three common training methods Copyright © 2023 Wolters Kluwer All Rights Reserved The Two Major Aerobic Training Goals Copyright © 2023 Wolters Kluwer All Rights Reserved High-Intensity Interval Training Repeated intense exercise with brief rest periods or low-intensity relief intervals that typically vary from 2 to 3 s to several minutes. As little as six sessions of near all-out effort over a 2-wk time increase skeletal muscle oxidative capacity and enhances performance. Four factors impact interval training prescription: Intensity, Duration, Length of recovery interval, Exercise-to-relief repetitions. In interval training, exercise intensity must activate the particular energy systems that require improvement. Copyright © 2023 Wolters Kluwer All Rights Reserved Overtraining Syndrome in Endurance Sports Copyright © 2023 Wolters Kluwer All Rights Reserved