Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
PDHPE Student Activities Comes to Life Energy Systems and Athlete Performance Adenosine Triphosphate (ATP) is required to perform any form of muscular contraction. Muscle cells only store enough ATP to generate 2-4 seconds worth of high-intensity exercise, therefore ATP must be continuously resynthesised via one of three energy systems. By using equipment from the UNE sports science laboratory, you will be able to identify the body’s physiological responses to exercise and consider why these changes occur. You will have the opportunity to participate in a number of tests, including vertical jump performance, maximal aerobic uptake (VO2max), and maximal power. Each of these tests has been included to assist you in your understanding of the energy systems, see how you stack up against your friends, whilst also having fun. Following the activities, you will be able to consider how this information can be used to set training for athletes with the end goal of improving performance. Activity 1: Vertical jump performance and anaerobic ATP resynthesis Performances of an athlete during high-intensity exercise are limited by the capacity of the body to resynthesis ATP quickly and remove waste products. Oxygen is important for the resynthesis of ATP, whilst CO2 is a waste product and must be removed. This activity is designed to demonstrate how vertical jump performance is affected with fatigue of the anaerobic energy systems. The person jumping will need to follow instructions from the UNE staff member, completing repeated vertical jumps over a period of 2 minutes. The goal is to maximise the height of each individual jump. This is tiring, so make sure you pace yourself accordingly. IMPORTANT: Let the supervisor know if your heart rate is over 80 beats per minute before you start the jumping, or if you are feeling unwell during the jumping. You can stop whenever you like. Before Exercise After Exercise Heart Rate O2 % Saturation CO2 Concentration (Breath) O2 Concentration (Breath Jump # 0 10 Jump Height (cm) RSI* Average Power (W) = Maximum Power (W) = Reactive Strength Index (RSI) 20 30 40 50 60 70 School of Science and Technology SUMMARY TABLE OF THE ENERGY SYSTEMS Each of the energy systems work together, however the contribution from each depends on the intensity and duration of the exercise being performed. With an understanding of the particular energy systems, we are able to set training plans which are specific to athlete needs. Metabolism Fuel Source Alactic (ATP/PC) Lactic Acid Aerobic Anaerobic Creatine Phosphate (PC) Anaerobic ONLY Carbohydrates (glucose and muscle glycogen) 16kcal/min 2 ATP Aerobic Carbohydrates, fats, or in some circumstances, protein 10kcal/min 1 glucose molecule= 36 ATP Rate of energy production 36kcal/min ATP produced from 1 1 ATP molecule of fuel source Duration Cause of fatigue By-products Recovery Intensity of effort Examples Max. Sprint of 8-10 sec PC depletion None PC replenishment 50% in 30 sec 100% in 2-5 mins Very high intensity (95100%) Jumping, throwing, short sprints Maximal, 30-60 sec Up to 3 minutes depending on relative intensity Accumulation of lactate and hydrogen ions (H+) Lactate and H+ ions Removal of lactic acid with active recovery in 15-30 min High intensity (85-95%) 400-m run, 100m swim, repeated sprints/ intervals (team sports) 1 fatty acid molecule= 130 ATP Maximal, 3-7 min Unlimited depending on intensity Glycogen depletion Change in pH affecting metabolic enzymes Carbon dioxide & water Depends on glycogen depletion; up to 48 hours Low intensity <VO2max* 5-km run, 1500-m swim, marathon *VO2max refers to the maximal volume of oxygen that can be used by the body in 1 minute Question: Given the evidence, which energy systems would have been dominant throughout the 2 minute jump activity? Would the contribution of each energy system have been consistent throughout the activity, or would this change throughout? How did your best vertical jump score compare to the Number 1 Draft Athlete in the 2012 National Hockey League (NHL) who achieved a jump height of 83 cm? Activity 2: Maximal Oxygen Uptake Testing (VO2max) The VO2max test is generally considered the best indicator of cardiorespiratory fitness, and is conducted by analysing the air inhaled and exhaled during an incremental exercise test to fatigue. The underlying principle behind the VO2max test is that almost every process in the human body is dependent on the availability of oxygen (O2) for muscle cells, and the removal of carbon dioxide (CO2) to control the pH of blood. Whilst your class member is completing the VO2max test, it is important for you to complete the table provided below, and consider the contribution of each energy system to ATP production at that point in time. TIME (min) SPEED/BEEP WATTS VO2 (mL. kg.min) CO2 % H.R. CHO % 2 4 6 8 10 12 14 16 18 20 22 Question: What does the VO2max represent? Question: What is the major limitation of the aerobic energy system? Complete the following table and consider why there is a shift from aerobic ATP resynthesis to anaerobic ATP resynthesis during the later stages of the VO2max test? Anaerobic Energy Systems ADVANTAGE DISADVANTAGE Aerobic Energy Systems Physiological Adaptations in Response to Training: Endurance based training has previously demonstrated an improvement in VO2max performance of 20-30%. The below table identifies the physiological adaptations in response to training which may improve an athletes VO2max score, and sporting performance. Heart Rate (HR) Stroke Volume Cardiac Output Adaptation Decreased resting and submaximal HR Increased at rest, and in submaximal and maximal exercise Increased maximal cardiac output Oxygen uptake Increased capillaries, myoglobin and mitochondria Increased enzyme activity Lung Capacity Increased maximal ventilation (VE) Haemoglobin Muscle Hypertrophy Muscle Fibres Increased Increased size with resistance training No change in slow twitch percentage Increased enzymes, ATP, PC and glycogen stores Increased motor unit synchronisation Increased use of fats as an energy source for muscles Consequences Heart works less- is more efficient More blood available per beat More blood and oxygen delivered to the muscles More oxygen delivered Muscles can extract more oxygen from the blood which is then available for ATP production Increased oxygen transport and removal of carbon dioxide More oxygen carried to the muscles Increased strength and power Increased power output before fatigue; more ATP available at the start of exercise Greater strength and power Less glycogen depletion, improved aerobic performance INTERESTING FACT: Training at intensities below the VO2max will contribute to improvements in aerobic ATP production, whilst working above VO2max will improve anaerobic ATP production. How do you compare? The highest VO2max ever recorded was 92mL/kg/min. INTERESTING FACT: The goal of endurance trained athletes is to perform for as long as possible using the aerobic system. By using fat as an energy source, this allows them to perform without the accumulation of lactic acid, and also helps to save muscle glycogen levels for later in the race. Activity 3: Wingate Testing The Wingate test is a 30-second all out sprint, identifying the power and fatigability of an athlete. If you wish to complete the 30-second exercise test, you must complete the Adult Pre-Exercise Screening Tool. During the test, your job is to cycle or run as fast as possible for the allotted 30 second period. Following the test, use the data provided to complete the tables below and assess how you match up against your classmates and/ or teacher! BIKE PERFORMANCE Time: 0-5 s 6-10 s 11-15 s 16-20 s 21-25 s 26-30 s Avg. Power: PERFORMANCE SUMMARY Bike: Power Peak (W) Power Peak/Weight (W/kg)* Power Average (W) Fatigue Factor (%) Power/mass (W/kg) Split 1 Split 2 Split 3 Total Distance Running: m/s m/s m/s m *Power peak/weight (W/kg) = Power peak divided by weight Question: What happened to your power output as the test progressed? Can you explain this? Question: how might this test be used or adapted to train for team sports, consisting of repeated sprints? How do you compare? In the 2012 draft for the National Hockey League (NHL) in America the number 1 draft athlete achieved a peak power output of 15.6 watts/kg with a fatigue factor of only 32%. Power (Watts)/Velocity (m/s) Graph: Power output vs. time Time (Seconds) Question: how might an athlete train to improve their Wingate test performance if they didn’t have a bike? INTERESTING FACT: Usain Bolt recorded the fastest running speed ever during the 2009 World Championships 100m sprint. He reached a velocity of 12.4 m/s (approx. 45km/h) between the 60th and 80th meter. Glossary Adenosine triphosphate (ATP) - energy source for all muscular contractions in the human body. Without ATP, we cannot live, let alone exercise! Cell - the human body is made up of millions of cells. ATP production starts in the cells. Once ATP is produced in the cell, muscles can use it to fuel contractions for exercise. Carbohydrates - the only fuel for ATP production during high-intensity (anaerobic) exercise. Examples of carbohydrates used for ATP production include glucose and glycogen: Glucose/Glycogen ➞ 2 Lactic Acid + Carbon Dioxide + 2 ATP Anaerobic ATP production - must occur during high intensity exercise when aerobic ATP production cannot keep up with the ATP demands of the muscles. The ATP/PC and glycolytic pathways are both anaerobic, occurring without oxygen. Rate of ATP production - increases with increasing exercise intensity. Lactic acid - product of anaerobic ATP production, causing performance to decline due to a change in the pH of blood. Aerobic ATP production - occurs more slowly than anaerobic, but can be sustained for long periods. Carbon Dioxide (CO2) - produced during the breakdown of carbohydrates to ATP. Higher carbon dioxide concentration of expired air means that ATP is being produced anaerobically. Waste product - produced during ATP production, and has a negative effect on athlete performance. Examples include carbon dioxide and lactic acid. SOURCE: Buchanan, D., O’Connor, D., McLean, J. & Ingram, K. (2009) Peak Performance 2: HSC PDHPE, South Yarra, MacMillan Education Australia. School of Science and Technology Produced by Marketing and Public Affairs UNE, April 2016. Information correct at time of printing. CRICOS Provider No. 00003G.