Physiological Principles of Training PDF

Physiological Principles of Training MEDI221/EXSC221 Learning objectives Describe the physiological determinants of endurance performance 3 ways in which aerobic performance ↑ with training… … and which of these is most important. Describe the physiological determinants of anaerobic...

Physiological Principles of Training MEDI221/EXSC221 Learning objectives Describe the physiological determinants of endurance performance 3 ways in which aerobic performance ↑ with training… … and which of these is most important. Describe the physiological determinants of anaerobic performance Anaerobic power Anaerobic capacity Stress -> Strain -> Adaptation Why train aerobic fitness? Health & Wellness Performance Sport (eg. endurance sport, or to aid recovery) Industry Recreation Extreme Environments: e.g. heat, altitude, expeditionary Help prevent or treat several conditions: e.g. CVD, Diabetes, Obesity, CHD, Hypertension)  Determinants of endurance performance (Distance, velocity, power) Training adaptations https://www.youtube.com/watch?v=6rqaP0dk2bg Your Turn Watch this clip- What are the determinants of performance? Discuss on Week 8 Forum.  Determinants of Endurance Performance Aerobic Capacity Lactate threshold want this to be higher Efficiency Energy use- saving glycogen stores Fuel depletion Aerobic power VO2max Cardiac output and oxygen extraction Main concepts of improving endurance performance Cardiorespiratory fitness is one of the strongest predictors of Mortality What is VO2max? Maximal oxygen consumption Maximal oxygen uptake Maximal aerobic power Plateau in oxygen consumption with increasing exercise intensity = VO2 max Delivery Extraction VO2 Max Decreases with Age Your Turn Q1. Why? Q2. What is the impact of training? Post to Week 8 forum Changes in VO2max with Age Max HR drops with Age ~ Linear effect HRmax = 220 – age (± 10 bpm) Due to ↓ adrenoreceptor sensitivity. Major component of the ↓ in maximal cardiac output with age. Also; Loss of muscle mass ↓ muscle quality? (disuse vs aging) ↓ mitochondria, ↓ oxidative enzyme, ↓ capillarisation, lower fat deposits and valve stiffness Main concepts of improving endurance performance 2. Lactate threshold Aerobic training allows for higher rates of lactate production and clearance at higher intensities An increase in the exercise intensity when blood lactate begins to accumulate Lactate accumulation reflects; ↓ PH (from H+) Substrate depletion NAD+ depletion Impairments in enzyme function = slower rate of energy production / anaerobic ↑ Lactate Threshold by ↓ Production and/or ↑ Clearance Economy ̇ 2 needed to maintain a given velocity of movement VO how much oxygen you use when running/walking at a given (sub- maximal) speed Efficiency Mechanical efficiency evaluates the relationship between work accomplished and energy expended doing the work Reflects how much chemical energy is converted to work, with remainder lost as heat ME (%) = External work accomplished ÷ energy use × 100 ME ranges between 20 to 25% for walking, running and stationary cycling ME declines below 20% for activities with substantial drag forces Principles of Anaerobic fitness Two energy systems contribute heavily. 1. ATP-PCr 2. Glycolysis “Anaerobic” fitness involves: Strength Power & speed Speed-endurance Rapid recovery High specificity Training the energy systems. Remember: Power of each system by stressing rate of ATP supply Capacity of each system by stressing duration of ATP supply (at highest rate). Muscular Power and Endurance Power: Maximal rate that work can be performed by a muscle or muscle group Power = Force x Velocity = Work / time Determined by the work done in a given time Endurance: ~max volume of force that can be applied. 20 Wingate test Anaerobic Power Anaerobic Capacity  Modeling short, very high intensity (~’anaerobic’) performance Very High Intensity Performance Resistance to Performance abilities Acceleration, velocity, sustained velocity, repeat bouts movement (eg: air, gravity, objects) Anaerobic Anaerobic Power Body mass Fat mass Capacity Phosphage Aerobic Glycolytic ‘Lactate n Phosphage Power Power’ Strength Capacity n Power Capacity Functional abilities MSST power Tolerance of H+ Distribution of & ionic effects power output &. (muscle, blood) technique VO2 max Motivation Pain Tolerance Glycolytic Phosphagen Muscle Muscle [Glycogen]m [ATP],[PCr] [Buffers] Neuromuscular mass enzyme enzyme composition (% Function (esp Type activity activity Type II) II) A Basis for Training Power & Capacity. Physical abilities  Revision: Strength = Amount of force that can be generated by a muscle or muscle group in one maximal voluntary contraction (MVC) At a particular velocity Is related to muscular power & endurance Depends on proportion of type II fibres Is relatively specific - limited transfer between: movement types muscle groups Factors affect force production? Force = mass acceleration CNS INPUT - inhibitory/excitatory TENDON TENDON MUSCULAR STRUCTURE INSERTION FORCE INTRINSIC MUSCLE PROPERTIES PROPRIOCEPTIVE INFORMATION PHOSPHOCREATINE RESYNTHESIS/ DEPLETION 24  How do we generate more force? To  force: Use more or bigger muscle(s) Recruit more motor units Access fastest & strongest fibres  Firing freq. of motor units  co-contraction of antagonists 25 Stress Strain Adaptation  Stress Strain Adaptation Environment Modulators Genetics (incl. sex) Resting status e.g., thermal energy Age, Training status, e.g., receptor Clinical status, etc sensitivities, muscle mass or Physical Activity Strain substrate mass Intensity, duration esp. [energy substrates], Responses Mechanical stretch, Ca++, (esp. genetic) Stress response Mode, frequency Cell volume, ROS, Heat characteristics e.g., effector sensitivities or Nutrition & Medications capacities Substrates (e.g., CHO, a.a.s) Water, vitamins, minerals Powers & Howley 8th Ed (2013) Fig 2.9