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Nelson Physical Education Units 3 & 4 Test your knowledge solutions Chapter 14 Nelson Physical Education VCE Units 3 & 4 Test your knowledge solutions Chapter 14: Performance enhancement: nutrition, diet and other considerations Test your knowledge p. 359 1 a More mobile players such as forwards are more likely to expend greater energy and are more likely to have prepared by increasing their carbohydrate intake in the week leading up to the game. They would also be more likely to need regular drinks during the game due to greater amounts of fluid loss, compared to less active players such as a goalie or players on the backline. b Players training with the national squad would have more frequent and demanding training sessions, both on the field and off the field (in gymnasiums, etc.). Therefore their needs for fuels would be higher (pre game and as a recovery strategy) and they are likely to have greater protein intake to assist repair and growth of cells. c Players performing on two consecutive days need to ensure that they are fully ‘refueled and rehydrated’. In addition to this they need to pay attention to rapid removal of by-products and care of muscles, joints, etc. to ensure optimal performance the next day. This might see the use of massage, hydrotherapy or other physical recovery methods. d It is likely that the players will not be greatly increasing the amount of carbohydrates consumed and insufficient information about timing of the meal and the semi-finals is provided – the foods at Hungry Macs would most likely be high in fats, protein and possibly salt, and not assist their ‘loading plan’. The players may feel bloated, dehydrated and ‘lacking energy’ the next day. 2 a, b & c Some people using illegal performance enhancing substances try to hide or “mask” them by taking diuretics in the belief that this will flush them out of their bodies. This is ineffective and leads to dehydration, cramping, the potential for elevated body temperatures and risk of losing consciousness, heat stroke, etc. Plasma expanders are used to increase the fluid/plasma component of blood and are commonly used in emergency wards to treat victims of burns, shock and trauma. Athletes can use these substances to dilute the concentration of banned substances such as EPO in their blood. Allergic reactions are sometimes experienced as side effects. Epitestosterone is a form of testosterone that doesn’t enhance performance. Most drug tests for testosterone measure the ratio of testosterone to epitestosterone and this is known as the T/E ratio. Athletes can inject epitestosterone in an attempt to lower the T/E ratio and hide the use of testosterone. Epitestosterone has no known harmful side effects. Many performance-enhancing drugs have structures shaped similar to organic acids. These organic acids are removed by a protein in the kidney that transports organic acids. If this protein can be blocked by using drugs that are known as ‘secretion inhibitors’, then they 1 Nelson Physical Education Units 3 & 4 Test your knowledge solutions Chapter 14 3 4 5 6 would not appear in the urine being tested. Allergic reactions, kidney problems and nausea are common side effects associated with secretion inhibitors. a Caffeine may improve performance by : acting as a stimulant for the CNS and the circulatory and respiratory systems possibly increasing fat oxidation leading to glycogen sparing contributing to more intense muscular contractions. b 3+ mg of caffeine per kilogram of body weight might contribute to improved endurance performance. c One of the largest side effects associated with caffeine consumption is its high diuretic effect. This may add to elevated body temperatures, resulting from increased fluid loss. Athletes performing in hot and humid conditions already struggle with fluid loss and rehydration, and do not need the added stress on their body that caffeine may enduce. a & b Research is currently being conducted on colostrum and performance enhancement. It is thought to potentially improve immunological and growth functions by increasing protein synthesis, both contributing to improved recovery mechanisms. a Men generally need more minerals than women due to their larger muscle-to-body-weight ratio and larger blood volumes and the function they play in growth and repair at these sites. b In general, premenopausal women need more iron than men due to menstruation. Women lose an average of 15 to 20 milligrams of iron each month during menstruation. c There is a finite amount of minerals that can be absorbed and stored by our bodies. Excess amounts are excreted. a Myth: Eating chocolate before an endurance event will provide you with extra energy and improve your performance. Large amounts of sugar or glucose should not be consumed less than one hour before exercise. The ‘sugar hit’ increases both blood glucose and insulin levels. As a result of high insulin levels, blood glucose is reduced during the exercise period, leading to hypoglycaemia. This leads to feelings of fatigue. It also lowers the availability of bloodborne glucose as a fuel, which in turn causes muscle glycogen to be used in greater amounts, speeding up the onset of muscular fatigue in endurance events. Myth: Salt tablets should be taken to replace salts lost through sweating and thus prevent cramps. Salt tablets remain in the stomach for long periods of time and result in the movement of water from the bloodstream to the stomach via osmosis. This leads to further reduction in performance and may contribute to stomach cramps and high blood pressure. Remember that each litre of sweat contains about 1.5 grams of salt, and twice this amount is found in the average meal. b Myth: Drinking water prior to activity will cause a ‘stitch’. Fact: No evidence exists to support this theory. In fact, there is as yet no scientific explanation of the cause of a ‘stitch’. It is thought that lack of oxygen to respiratory muscles (diaphragm and intercostal muscles) due to insufficient blood flow is implicated. Fluid intake prior to an activity is advisable, particularly prior to heavy exercise in hot weather. Fluid loss may amount to two litres per hour. Fluid intake is critical, in that it replaces the fluid lost and allows the body to cool itself continually by sweating, thus preventing the body temperature from rising. Insufficient fluid intake may lead to heat stress, heat exhaustion, heat stroke and even death. More dietary myths (and facts) can be found at : http://www.peakperformance.on.ca/health/1myths.htm#1 2 Nelson Physical Education Units 3 & 4 Test your knowledge solutions Chapter 14 c Vitamins and minerals taken in excess can cause toxicity problems, or affect the body’s ability to absorb or retain other nutrients. For further side effects associated with vitamin and mineral ‘overdose’, visit http://nutrition.tufts.edu/consumer/balance/200311/vitaminod.html and consult the table provided. d Any recommendations should involve a balanced diet (avoiding foods high in fat content) with exercise (mainly using the aerobic system and utilising fats as a fuel) that is appropriate to the level of person’s fitness. The person must aim to have a negative energy balance where more calories are used as energy than those consumed in foods. With increased exercise levels it makes sense to recommend increased water intake (calorie free!). It is important that the myth of ‘spot reduction’ be explained along with decreased fat/increased muscle ratio that is likely to accompany increased exercise levels. 7 a Branched-chain amino acids may: minimise protein breakdown and contribute to increased muscle mass when combined with a resistance training program delay fatigue caused by transmitter tiredness aid in haemoglobin production. NB. More research needs to occur in this area! b These protein foods that are high in branched-chain amino acids will contribute to energy production of assist in cell repair and growth. c Transmitter tiredness (depletion of Acetylcholine – Ach) can be countered by either reducing the intensity of the activity or taking regular breaks as allowed during the performance (use of interchange facility) to allow it to be resynthesised. Dietary choline and phosphatidylcholine serve as the sources of free choline for acetylcholine synthesis. Foods high in phosphatidylcholine content (major delivery form of choline), are beef liver, egg yolks and soya. Beef liver, iceberg lettuce, peanuts and cauliflower are some foods that contain free choline. These foods assist in the resynthesis of Ach. 3