ANSWERS TO CHAPTER REVIEW QUESTIONS

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1 (b) The use of CHOs for ATP production greatly increases at around 85 per cent VO 2 max because the body is entering anaerobic metabolism that uses only CHOs as a source. Below 85 per cent there may be some use of fat for ATP production. 8. (a) mmoi/l lactic acid 3 9 Anaerobic systems Aerobic system Exercise intensity Figure 2.22: Probable LIP for an elite AFL player (b) Because the athlete is working anaerobically, the high lactate and hydrogen ions levels force the body to go into an oxygen deficit situation. (c) Lactate threshold is defined as the exercise intensity that brings on substantial increase in blood lactate during a single incremental test. This can be between 3 and 9 mmol/l. OBLA is defined as the exercise intensity at which blood lactate concentration reaches 4 mmol/l during an incremental test. 9. (a) Line A: slow jog Line B: 400-metre athletic race Line C: a fitness run, swim or cycle, in which the level of effort is at a steady state Line D: a 3000-metre athletic race with a number of surges during the race; or a triathlon cycling leg where there are a number of hills. (b) Because the body always has some lactic acid in it (c) Because at the onset of exercise, lactic-acid levels increase. If the exercise levels remain below the lactate threshold, then spare oxygen is available to work on the accumulated lactic acid and convert it to ATP stores and at the same time reduce the lactic acid levels in the bloodstream. 10. (a) Based on data from figure 2.20, possible reasons include: Freeman would have a higher tolerance to her building lactate levels. Freeman s phosphate energy system has a greater capacity to enable her to continue using this source of ATP production for longer than the other runners. Because she may have more disposable oxygen, Freeman is able to more efficiently metabolise the building lactic-acid levels into new ATP. Freeman has higher levels of the relevant enzymes needed for both the and anaerobic glycolysis energy systems. (b) The system (also known as the Phosphate, PC, or CP system) (c) Because the body is effecting an explosive change from stationary inertia to moving inertia, both maximal speed and strength are needed for this; hence, the quickest available source of ATP production is employed. (d) During the third 100-metre split of the race, each of the runners displays a drop in running speed. This represents a significant drop when compared to the second, where each of the runners achieved their fastest 100-metre split. Only the OBLA and building blood levels of lactic acid and hydrogen ions can cause this. (e) The OBLA occurs when the normal resting circulatory system levels of lactic acid and hydrogen ions begin to rise, as anaerobic glycolysis causes intra-muscular levels of each to rise and disperse into the circulatory system. At the same time, blood plasma levels of H + have an effect on the contractile abilities of actin and myosin. In both aerobic and anaerobic activities, the OBLA is not a cause of diminishing performance. (f) Because of Freeman s highly trained state and her ability to tolerate high levels of lactic acid and hydrogen ions, she would be able to continue to function smoothly at high levels. At the end of the race these could be mmol/l lactic acid blood levels. Elite athletes have been measured at much higher levels while still being able to carry out lactate tolerance training. However, as the 400-metres is a one-off anaerobic effort of only around 50 seconds, Freeman s post-race levels would not have been maximal. Her ability to keep functioning fairly smoothly under these anaerobic conditions is possible because of the interval training she would have carried out. This training would have stressed and trained her body s lactate tolerance. (g) For LT 3 9 mmol/l For OBLA 4 mmol/l (h) The discomfort caused by the unfit individual reaching their LIP would have adversely affected their running style due to a lack of 404

2 familiarity with the feeling. Their body s ability to continue smooth performance would be significantly more noticeable than Freeman s. (i) Refer to the pie charts in figure 2.23 below. First 200 m of race Second 200 m of race Total race time 25% Aerobic glycolysis 30% 45% 65% <5% Aerobic glycolysis 30% 55% 35% 10% Aerobic glycolysis Figure 2.23: Percentage estimate contributions of the three energy systems at stages of the race (j) Reasons for the divisions in each of the three pie charts are included below. First 200 metres: The PC system is important for the drive from the starting blocks and the achievement of the desired top speed. The anaerobic glycolysis system begins to create a lot of ATP from about 3 5 seconds, along with the associated increase in lactic acid and hydrogen ions. From about seconds, the aerobic glycolysis system begins to contribute ATP to the energy needs of the event. Last 200 metres: The PC input has become negligible, as its primary importance was in the acceleration phase of the race. With the building lactate and hydrogen ions during the third 100-metre split, the efficiency of the anaerobic glycolysis has deteriorated. Matching this has been the growing importance of the aerobic glycolysis system in creating the required ATP for the race. Total race needs: Because the running time is around 50 seconds, the split between the anaerobic and aerobic systems in terms of ATP production slightly favours the anaerobic systems. 11. (a) >95% of max HR; <10 seconds activity time (b) Responses could include: 100-metre elite male athletic sprint; 60-second athletic sprint for most adult males and females; any athletic field event; springboard diving; cycling velodrome 200-metre sprint; individual skill movements in most team games. (c) Advantages: Produces quickly Allows quick transfer of stationary-tomoving inertia Quickly replenishes, enabling repetition of duplicate effort within 5 minutes of first effort Does not rely on energy sources from outside the muscle Does not rely on oxygen being available. Disadvantages: Depletes quickly Only allows maximal effort up to 10 seconds Relies on muscle stores of ATP and PC Needs aerobic conditions to replenish ATP and PC stores. 12. (a) 85 95% max HR; 5 35 seconds activity time (b) Responses could include: 400-metre athletic track race; cycling velodrome male 1-kilometre time trial; elite male and female 100-metre swim race. ANSWERS TO CHAPTER REVIEW QUESTIONS Answers to Chapter Review Questions 405

3 (c) Advantages: quickly available enables near maximal effort for longer than ATP APC energy system does not rely on oxygen being available does not rely on energy sources from outside the muscle quick recovery time aided by active movement toxic by-product (LA) is able to be metabolised to ATP during aerobic recovery. Disadvantages: not as quickly available as energy does not enable effort for as long as the aerobic energy system cannot rely on oxygen being available can only use energy sources from within the muscle requires active recovery time to promote the return to active movement toxic by-products (LA and H + ) reduce the smooth action of the crossbridges within the sarcomere. 13. Australian Football is a fine example of a team sport that demands fitness across all components and energy systems. Muscular strength is needed for tackles and man-on-man contests; it combines with speed for the necessary muscular power to accelerate into space or away from an opponent, to leap for marks, or create clearing kicks or attacking handballs. Energy for each of these skills individually comes from the system. However, as the game progresses and the range of skills needs continual repetition, the required recovery time of at least three minutes is generally unavailable. Therefore, the body gradually becomes more dependent on the anaerobic glycolysis system to create ATP. This is reasonably effective but comes at a price. The LIP and the building lactate and hydrogen-ion levels make the player become aware of fatigue and an increasing desire for rest. Underlying all these efforts is the aerobic glycolysis system. This is continually making ATP generally available for bodily needs, but is also working to create new stores of ATP and PC within the working muscles. When enough oxygen is available, it is also reworking lactate into renewed ATP stores within the muscles and body systems that may not be working as hard as the muscles. Agility and its aligned flexibility are needed to evade opponents and turn quickly to kick, handball or tackle in unexpected situations. Local muscular endurance, with the many repeated efforts (see Chapter 5 for activity analysis), is essential for the successful completion of the game. Aerobic power is the underlying fitness component, with top players like Luke Ball covering up to 20 kilometres or more in one game, while having to sprint and complete precise power movements throughout this impressive total distance! CHAPTER 3 Conversion of food to energy 2. Recommended daily percentages of carbohydrate, fat and protein are as follows: Carbohydrate: per cent Fat: per cent Protein: 15 per cent 3. Vitamins assist chemical reactions in the body by formulating parts of enzymes or coenzymes, which assist in the metabolism of carbohydrate and fat. Minerals play an important role in muscle contraction, nerve transmission, fluid balance and assisting enzymes in energy production. 4. Unsaturated fat is the most beneficial form of fat to consume as the body cannot produce it. Unsaturated fat also reduces low-density lipoproteins (which are responsible for blocking arteries). 5. A weight-lifter needs fuels that can supply energy for high-intensity, short-duration activities. Stored phosphocreatine and glycogen supply energy for these activities. A long-distance runner requires fuels that can supply the body over a long period of time, but at a sub-maximal workload. Glycogen and fat are necessary fuels for this particular athlete. 6. Water is suitable for exercise lasting minutes. Beyond that time frame, sports drinks that contain carbohydrate and electrolytes are essential to replace fluid, as well as the sodium and potassium lost in sweat. 7. Thirst is a sign of dehydration. If you do not drink until this point then your body is already dehydrated and your performance may already be suffering as a consequence. 8. By knowing a food s glycemic index, an athlete is better able to decide the most beneficial time to ingest that particular food. 9. Foods that have a low glycemic index take longer to digest and release energy over a longer period. These are best ingested prior to activity for sustained energy without the insulin surge. 10. A high-gi index food releases sugar rapidly into the system and raises blood glucose levels. This results in insulin being released by the pancreas informing the working muscles that they should 406

4 not take up more blood glucose. The muscle cell glucose level is then compromised, leading to fatigue and hunger. Therefore, a high-gi food should not be ingested as part of a pre-event meal. Sugary foods with a high glycemic index are best ingested during recovery, as they rapidly release glucose to muscles to replace the muscle glycogen stores consumed during exercise. CHAPTER 4 Fatigue and recovery 2. Three factors influencing the causes of fatigue are: The type of activity being undertaken The intensity of activity being undertaken The fitness level of the athlete. 3. The three levels of fatigue are: local, general and chronic. Local fatigue is experienced in a particular muscle or group of muscles following a specific training session or performance (e.g. quadriceps following 30 seconds of squats). General fatigue is an overall body fatigue as a result of an extended training program (e.g. after a weights session at the gym). Chronic fatigue is long-term fatigue caused by the body s defensive mechanisms breaking down over time. This fatigue can be a combination of both mental and physical fatigue. 4. Common causes of fatigue in athletes include: Fuel depletion Metabolic by-products Dehydration and increased body temperature. 5. Causes of fatigue within anaerobic and aerobic activities are shown in the table below: Athletic event 100-metre sprint 200-metre swim Halfmarathon Hawaiian ironman Specific cause of fatigue PC depletion LA and H + accumulation LA and H + accumulation, glycogen depletion and dehydration LA and H + accumulation, glycogen depletion, fat depletion and dehydration 6. Fast-twitch fibres fatigue as a result of fuel depletion and lactic acid and hydrogen ion accumulation. On the other hand, slow-twitch fibres tend to fatigue as a result of glycogen depletion and dehydration. 7. Lactic acid accumulation specifically causes a decrease in the secretion of calcium ions that enable the coupling of the actin and myosin protein filaments. Without sufficient calcium ions the protein filaments cannot attach to each other. The sliding of the protein filaments is then not possible. LA accumulation also inhibits the action of glycolytic enzymes that prevents glucose from breaking down glucose being the food fuel for both anaerobic and aerobic glycolysis. Hydrogen ion accumulation results in the levels of cell ph decreasing to an extent that muscle contraction is no longer possible, and fatigue occurs. The low ph created by the hydrogen ions causes the glycolytic enzymes to become inoperative. Without the glycolytic enzymes the breakdown of glucose cannot take place. 8. Three symptoms of dehydration are: lightheadedness/dizziness, clammy skin and profuse sweating. 9. Urine that is stronger, and more orange than yellow in colour, indicates dehydration. Normal hydration urine is usually a faint yellow colour. 10. Ensure that you are well hydrated before, during and after training. Avoid caffeine and sugar drinks, as they induce thirst. Wear light coloured, breathable clothing so that sweat is drawn away from the skin, and use an ice-vest or cooling rooms as a way of regulating body temperature during breaks in training. Train early or late in the day, utilising the shade as much as possible. 11. An athlete is trying to regain their pre-exercise body condition. To do this they will have to address the following: Replenishment of stores Restoration of muscle and liver glycogen stores Breakdown and removal of lactic acid Rehydration Repair of damaged muscle tissue. 12. Venous pooling occurs when insufficient pumping of the muscles returns blood flow back to the heart, causing blood to pool in the inactive muscles of the lower extremities. 13. During the cool-down, the amount of oxygen being consumed by the body is still well above resting levels. This phenomenon is known as the oxygen debt and has two distinct functions: To replenish muscle stores of phosphocreatine (known as the alactacid phase of oxygen debt) To breakdown and remove lactic acid (known as the lactacid phase of oxygen debt). 14. The restoration of muscle glycogen stores requires the following essential elements: The greater the depletion of glycogen stores, the faster the rate of recovery. Intake of carbohydrate must take place within 30 minutes ANSWERS TO CHAPTER REVIEW QUESTIONS Answers to Chapter Review Questions 407

5 of cessation of activity in the amount of grams of CHO per kilogram of body mass. High GI snacks or meals should be ingested in either liquid or solid form. Supplements of protein within these meals will also help with repair of damaged muscle tissue. 15. A combination of sweating and post-exercise urination causes dehydration in the athlete. 16. Sports drinks do not just rehydrate, they also replace glycogen and lost electrolytes. The sodium contained within sports drinks also helps with reduction of urine following exercise. However, if fluid losses are high, sports drinks may not be enough to both rehydrate and replace sodium losses. 17. Discuss the various 5-step plans during class time. Compare the plan for your chosen athlete with those developed by other class members. 18. The banana is a high-gi food source and will therefore be quickly digested and provide a ready source of glucose for the player during the match. The player should also be ingesting a sports drink that has high levels of CHO as well as the correct balance of electrolyte supplements for this player s individual needs. CHAPTER 5 Fitness components, muscles and activity analysis 2. (a) Anaerobic power, muscular strength (MS), muscular power (MP), speed, agility, local muscular endurance (LME), flexibility, and aerobic power (b) The table should reflect ratings similar to those shown below: Netball AFL Basketball Tennis Hockey Volleyball Anaerobic power MS MP Speed Agility LME Flexibility Aerobic power Team games have more physiological fitness components, mainly because of the range of movements and the higher, more varied exertion levels. Once a range of exertion levels is encountered within one game or event, the lactate threshold becomes relevant and the interplay between the anaerobic and aerobic energy systems is central to effective performance. 4. Flexibility is central to training sessions because effective performance in any activity requires the ability to perform specific movements. This means that the required muscles and joints need to be able to move through their full specific ranges of movement. 5. (a) to (c) to be done by individual students and discussed in class groups 6. Students should subjectively decide on a performer to assess, complete the assessment and discuss this with others in class. 7. (a) Aerobic power because the constant and regular exercise will sufficiently train their cardio-circulatory respiratory systems (b) LME to some extent but not to a high degree, as the posties LIP is unlikely to be challenged during a day of careful riding between letter boxes. (Also, dynamic balance will be improved by regular cycling.) 8. All three methods of flexibility training need to be carried out when the individual is thoroughly warmed up, preferably at the end of a training or competitive session. 9. (a) Static stretching requires the individual to assume a stretched position of the muscle and to hold this for seconds. This should create a degree of discomfort, but no pain. (b) PNF stretching can be done with a partner or by using a fixed platform for resistance. This method centres on assuming a comfortably stretched position for the specific muscle, performing a 6-second isometric contraction of that muscle, then moving to an increased static-stretch position. This movement may be repeated. 10. Ballistic stretching involves carrying out a game or activity where the muscles and joints are moving through the specific movements needed for competition. Three examples from three different sports are: Australian Football kicking, handball, marking Netball passing, shooting, defending Basketball guarding, long passing, dribbling. 408