Aerobic Exercise PDF

Aerobic Exercise – The Basics Outline  Aerobic energy production  Skeletal muscle  Response to Exercise  Exercise prescription   ATP  an energy-bearing molecule composed of carbon, hydrogen, nitrogen, oxygen, and ph...

Aerobic Exercise – The Basics Outline  Aerobic energy production  Skeletal muscle  Response to Exercise  Exercise prescription   ATP  an energy-bearing molecule composed of carbon, hydrogen, nitrogen, oxygen, and phosphorus ATP atoms Production  Used in all cellular actions requiring energy.  Muscle cells have limited capacity to store ATP  Cells continuously create ATP at a rate equal to ATP use. Biological Energy Systems  Three basic energy systems exist in muscle cells to replenish ATP:  Phosphagen system  Glycolysis  Oxidative system Energy and Work  Anaerobic energy sources  In short, explosive events (e.g., shot put) requiring maximal effort for less than 2 min PC breakdown and glycolysis provide rapid sources of ATP  Aerobic energy sources  During prolonged exercise (maximal work lasting more than 2 min and in all submaximal work) ATP is supplied by the aerobic metabolism of carbohydrate and fat in the mitochondria of the muscle Role of Aerobic and Anaerobic Energy Sources in Best-Effort Runs Energy and Work Immediate energy Short-term energy Long-term energy sources sources sources Aerobic; occurs in the Anaerobic Anaerobic mitochondria Glycolysis (breakdown Muscle glycogen, ATP/PC of CHO) glucose, plasma FFA Maximal work, >2 Maximal work, 1-5 Maximal work, 6.0 METs  Jogging (5mi/hr), skiing, snow shoveling, horseback riding, swimming (40 yds/min), singles tennis Expressing CRF Values Unit of measure Interpretation Liters of O2 used by the body L min -1 each minute Milliliters of O2 used by each ml  kg-1 min-1 kilogram of body weight each minute Multiples of resting metabolic METs rate (1 MET = 3.5 ml  kg-1 min-1) https://www.youtube.com/watch?v=D_i5bdhpUv0 Maximal Aerobic Power in Healthy and Impaired Populations Impact of Endurance Training  Increased reliance on fat as a fuel, sparing carbohydrate  Decreased time to submaximal steady state  Increased ventricle size, VO max, SV, and 2 O2 extraction  Training effects specific to trained muscles  VO max can be maintained through intense 2 exercise, when duration and frequency are reduced Skeletal Muscle  Converts chemical energy of ATP into mechanical work  Sarcomeres: fundamental units of muscle contraction  Contain thick filament myosin and thin filament actin  Bound by connective tissue called the Z line Muscle Fiber Types and Performance Fiber Type Description Primary ATP source Type IIx (fast Fast contraction, high Anaerobic: PC glycolytic) force, easily fatigue breakdown and glycolysis Type IIa (fast Fast contraction, high Both anaerobic, and oxidative force, resist fatigue aerobic glycolytic) Type I (slow Slow contraction, low Aerobic oxidative) force, resist fatigue Muscle Fiber Types: Genetics, Sex, Training  Distribution is highly variable and strongly influenced by genetics  Training does not convert fast-twitch fibers to slow- twitch and vice versa  Training increases mitochondrial number and capillary density (oxidative capacity) Fiber type differences  Cardiovascular Responses to Acute Exercise  Increases blood flow to working muscle  Involves altered heart function, peripheral circulatory adaptations  Heart rate  Stroke volume  Cardiac output  Blood pressure  Blood flow  Blood CO and SV during Exercise  Respiratory Response to Exercise  Respiratory changes needed to: 1. supply the increased amount of O2 needed 2. expire excess CO2 produced Changes Include:  respiratory rate  gas exchange  tidal volume Neuromuscular Responses Providing Increased O2 to the Muscles Increased blood flow to the working muscles Increased CO2 Increase O2 extraction from the blood to tissue Art of Exercise Prescription  The proper dose of activity is dependent on the desired effect or goals of the individual client  The dose of exercise needed for achieving better health differs from that needed to achieve peak performance  You wouldn’t have an Olympic athlete do the same work out as beginner! Exercise Dose (FITT-VP) The dose of physical activity/exercise is described in the FITT- VP principle: Frequency of exercise Intensity of exercise Time (duration) of exercise Type of exercise Volume of exercise: product of frequency x intensity x time Progression: transitioning from easier to harder exercise over time FITT-VP: Frequency Frequency  Training frequency is the number of training sessions conducted per day or per week.  The frequency of training sessions will depend on the interaction of exercise intensity and duration, the training status of the athlete, and the specific sport season.  Intensity  A combination of moderate (65% to FITT-VP: 80% HRmax) and/or vigorous-intensity (80% to 90% HRmax) exercise is Intensity recommended for most healthy individuals.  Adaptations in the body are specific to the intensity of the training session.  High-intensity aerobic exercise increases cardio-vascular and respiratory function and allows for improved oxygen delivery to the working muscles.  Increasing exercise intensity may also benefit skeletal muscle adaptations by affecting muscle fiber recruitment.  Intensity  Intensity may be FITT-VP: prescribed using multiple methods Intensity  Examples include heart rate reserve, rating of perceived exertion, percent VO2 max, and percent of age-predicted maximal heart rate.  Heart rate  The most frequently used method for prescribing aerobic exercise intensity Heart Rate Calculations  Target heart rate calculations  Karvonen method  Age-predicted maximum heart rate (APMHR) = 220 – age  Heart rate reserve (HRR) = APMHR – resting heart rate (RHR)  Target heart rate (THR) = (HRR × exercise intensity) + RHR  Dothis calculation twice to determine the target heart rate range (THRR)  Target heart rate calculations  Percentage of maximal heart rate method  Age-predicted maximum heart rate (APMHR) = 220 − age  Target heart rate (THR) = (APMHR × exercise intensity)  Ratings of Perceived Exertion  Ratings of perceived exertion scales  Can be used to regulate intensity of aerobic endurance training across changes in fitness level  May be influenced by external environmental factors  The perceived exertion method is another subjective rating of how hard one may be working.  Measured through Borg’s Rating of Perceived Exertion (RPE) Scale, which ranges from 6 to 20, 6 meaning no exertion at all, and 20 meaning maximal exertion.  The RPE range of 11 to 16 is recommended to improve cardiorespiratory fitness.  Borg’s Scale (CR-10): 0 to 10 scale; moderate (CR 5 to 6) and vigorous (CR 7 to 8). Intensity Spectrum: %VO2max The range for typical apparently healthy is 60 to 80% VO2max Intensity Spectrum: %HR max The range for typical apparently healthy is 75 to 90% HRmax   The talk test is a subjective measure of Talk Test Method relative intensity, which helps differentiate between moderate and vigorous physical activity.  If an individual is able to talk, but not sing, the physical activity is considered moderate.  Once the intensity of the activity increases to a point at which an individual is not able to say more than a few words without pausing for a breath, the intensity would be considered vigorous. FITT-VP: Time Time  Exercise duration is the length of time of the training session  The duration of a training session is often influenced by the exercise intensity; the longer the exercise duration, the lower the exercise intensity  Type FITT-VP:  All types of physical activity are beneficial as long as they are of Type sufficient intensity and duration.  Rhythmic, continuous exercise that involves major muscle groups is the most typical  Intermittent exercise such as interval training or stop-and-go sports may be used to accumulate the recommended frequency, intensity, and time needed for cardiorespiratory fitness  The more specific the training mode is to the sport, the greater the  Volume FITT-VP: Made up of the time, frequency and intensity of the program Volume  Used to estimate the total amount of “work” an individual complete over the course of week, or entire program Use metabolic equations to figure out calorie expenditure for a week Pedometer looking at amount of steps per day or week  Progression  Progression of an aerobic FITT-VP: endurance program involves Progressio increasing the frequency, intensity, and duration n  Frequency, intensity, or duration should not increase by more than 10% each week  When it is not feasible to increase frequency or duration, progression can occur with intensity manipulation  Progression of intensity should be monitored to prevent overtraining Guidelines for Increasing CRF  Encourage screening, regular participation, and variety  Use a program that focuses on progression Increase duration (e.g., 10% per week) or frequency before increasing intensity Use interval training to transition to continuous vigorous activity  Follow a formatted fitness workout Include warm-up and cool-down (5-10 minutes each) Stretch  Conduct periodic CRF testing Set goals for improvement (10% improvement in 3 mo) Effects of Increased Frequency, Duration, and Intensity on VO2max Recommendations for Achieving Health, Fitness, and Performance Goals Types of Aerobic Endurance Training Programs  Long, slow distance training  Training distance greater than race distance (or 30 minutes to 2 hours)  Intensities equivalent to 70% of VO2max  Adaptations from this exercise include the following:  Enhances the body’s ability to clear lactate  Causes an eventual shift of Type IIx fibers to Type I fibers  Intensity is lower than that of competition, which may be a disadvantage if too much LSD training is used. Types of Aerobic Endurance Training Programs  Pace/tempo training  Intensity at or slightly above competition intensity, corresponding to the lactate threshold  Steady pace/tempo training: 20 to 30 minutes of continuous training at the lactate threshold  Intermittent pace/tempo training: series of shorter intervals with brief recovery periods  Objectives  Develop a sense of race pace and enhance the body’s ability to sustain exercise at that pace  Improve running economy and increase lactate threshold Types of Aerobic Endurance Training Programs  Interval training . Exercise at an intensity close to VO2max for intervals of 3 to 5 minutes. Work:rest ratio should be 1:1.  This allows athletes to train at intensities close to VO2max for a greater amount of time.  It increases VO2max and enhances anaerobic metabolism.  Interval training should be used sparingly, and only when training athletes with a firm aerobic endurance training base. Types of Aerobic Endurance Training Programs  High-intensity interval training (HIIT)  Uses. repeated high-intensity bouts interspersed with brief recovery periods.  Athletes need to spend several minutes above 90-95% of VO2max for an optimal stimulus.  May be effective for improving running economy and running speed.  An example for long-interval HIIT is ≥2 to 3 minutes at 90% VO2max, with relief bouts of ≤2 minutes. Types of Aerobic Endurance Training Programs  Fartlek training  Combines other methods of training  Easy running (~70% VO2max) combined with hills or short, fast bursts (~85-90% VO2max)  Can be adapted for cycling and swimming  Benefits are likely to include  Enhanced VO2max  Increased lactate threshold  Improved running economy and fuel utilization Exercise Program  Purposes:  Increase levels of fitness for healthy individuals  Slow the decrease in functional capacity with age  Recondition those who have been ill or who have chronic disease  Three Components to ALL Exercise Programs  Warm-Up Period  Aerobic Exercise Period  Cool-Down Period Warm-Up Period  Purpose  Lag time between onset of activity and body responses; facilitates adjustments needed  Prevents or decreases susceptibility to musculoskeletal injury or ischemic cardiac changes  Physiologic Responses  muscle temperature muscle contraction, rate of nerve conduction and extraction of O2 from the blood  Dilation of previously constricted capillaries facilitates venous return  Guidelines  10 minutes of total body movement (e.g., calisthenics, slow walking)  To achieve HR to within 20 beats/min of target HR  Cool-Down Period  Purpose  Prevent pooling of blood in the extremities  Increases venous return to heart  May help to prevent myocardial ischemia, arrhythmias and other cardiac complications  Enhances recovery by removing waste products and replenishing energy stores  Like the warm-up it should include 5-10 minutes of total body movement (e.g., calisthenics, slow walking)  Key Point The various types of training induce different physiological responses. A sound program should incorporate all types of training into the athlete’s weekly, monthly, and yearly training schedule A sound year-round aerobic endurance training program should be divided into sport seasons with specific goals and objectives designed to improve performance gradually and progressively References  Kisner, Colby and Borstad (2023) Therapeutic Exercise, 8th edition. Philadelphia: FA Davis  American College of Sports Medicine: ACSM’s Guidelines for Exercise Testing and Prescription, 11th edition. Philadelphia: Lippincott Williams & Wilkins  Howley & Thompson (2017) Fitness Professional’s Handbook, 7th edition. Champaign: Human Kinetics  National Strength & Conditioning Association: Essentials of Strength Training and Conditioning, 4th edition. Champaign: Human Kinetics