PERFORMANCE ENHANCEMENT Text between pages 164 and 170 answers to questions on page 170 of the text book. 1) a) How does dehydration affect heart rate, body temperature and exercise performance? 3 marks Water loss during exercise increases because as heat in the body increases, more water is lost with increased sweating. Excessive loss of fluid impairs performance as blood plasma volume decreases. When dehydration reaches 2% of the body weight, aerobic endurance is notably impaired. And heart rate and body temperature increase in response to dehydration. b) How is body water balance maintained during prolonged aerobic exercise? 3 marks Water balance depends on the electrolyte balance. But the need to replace lost body fluid is greater than the need to replace lost electrolytes. Because sweat is very dilute. It is important to drink water at regular intervals during prolonged aerobic exercise. To reduce the risk of dehydration. And optimise cardiovascular and thermoregulatory functions. c) What are the potential benefits of using sports drinks? 3 marks Sports drinks are designed to supplement energy, fluid and protein needs of the athlete. When taken during exercise the carbohydrate concentration of a sport drink should not exceed 7% to maximise both sugar and fluid intake and absorption. This is known as a isotonic sport drink because the dilute level of glucose is the same level of concentration as in the blood. An isotonic sport drink is an important source of energy during exercise. And reduces the risk of dehydration. During recovery, hypertonic drinks contain much higher levels of glucose up to 20%. This highly concentrated drink is used to replenish depleted glycogen stores. And should be drunk as soon as the exercise period has been completed. 124
EXERCISE AND SPORT PHYSIOLOGY 2) Give a brief outline and comment upon the following techniques, which may be employed in the belief that they will enhance sport performance: the use of recombinant human growth hormone (rhgh), gene doping, creatine supplementation and caffeine. In your answer highlight the potential risks known to be associated with the use of each of these techniques. 20 marks 5 marks for the use of recombinant human growth hormone (rhgh): rhgh is an illegal ergogenic aid cloned through genetic engineering. Mimics body s naturally occurring hormone HGH. Which increases protein synthesis, lean body mass, blood glucose levels, stimulates bone growth and aids healing of musculoskeletal injuries. Therefore increases the performer s capacity for training. Hence, can potentially increase performer s strength. Muscle joint weaknesses. Acromegaly causes thickening of hands, feet and jaws. Enlargement of internal organs. Causes glucose intolerance, diabetes, hypertension and heart disease. 5 marks for the use of gene doping: Gene doping is the non-therapeutic use of cells, genes or genetic elements that are used to improve athletic performance. Because these protein chemicals are indistinguishable from their natural counterparts they would not be detected in a blood or urine test. For example, insulin-like growth factor (IGF-1) would carry a performance-enhancing gene and splice into a muscle cell to increase muscle mass and achieve muscle hypertrophy. Risks: Currently no-one knows about the potential side effects. 5 marks for the use of creatine supplements: Creatine supplementation is a legal ergogenic aid. Creatine is a natural substance found in skeletal muscle. And stored as phosphocreatine. Creatine supplementations increase PC levels. To enhance the ATP-PC energy system. Resulting in an increase in peak power output. And delay of the alactic or lactic threshold. Can cause muscle cramps. Excess intake effects not known. Leads to weight gain. 5 marks for Ingestion of drinks containing caffeine: Caffeine is a legal stimulant. Usually ingested in coffee or tea or coca cola. Keeps performer alert by diminishing effects of fatigue. Increases metabolic rate or heart rate. Increases mobilisation of free fatty acids (FFAs). Thus sparing muscle glycogen. Therefore aids endurance performers by increasing time to exhaustion. Acts as a diuretic, leading to dehydration. And associated increases in body temperature above optimum. Can produce a state of nervousness or anxiety. Can disrupt normal sleeping patterns. And contribute to fatigue. Abrupt discontinuation of caffeine intake can lead to severe headaches. Chapter 26 125
3) Cryotherapy methods are used as aids to recovery and rehabilitation for the elite performer. Briefly describe how an ice bath can assist in this process. 3 marks Ice baths use the fact that chilling the affected area can reduce local tissue inflammation. The effect of chilling is to decrease cellular metabolism, decrease inflammation, pain and spasm and promote vasoconstriction. Ice baths are used to reduce joint and muscle inflammation produced by microtears in stressed tissue. Reduce muscle soreness (DOMS) and aid recovery of local damaged tissue. Precautions should be taken because prolonged application at very low temperatures could have detrimental effects (for example frost bite). 4) Briefly describe an illegal ergogenic aid that would be of benefit to an endurance athlete. How would the use of this aid help performance, what are the health risks and how is the aid detected? 7 marks There are several possible illegal ergogenic aids and so one from the following: Blood doping refers to any means by which a person s total volume of red blood cells can be increased. It is often achieved by transfusion of red blood cells previously withdrawn from the recipient or a compatible donor. Temporarily increasing the number of oxygen carriers. Increasing the oxygen carrying capacity of the blood. Allowing more oxygen to be delivered to the active tissues. Thus aerobic performance can be substantially improved. Health risks include the problem of mismatching. Which can lead to a transfusion reaction or allergic reaction. Because of increased red blood cell count the blood becomes too viscous. Could cause blood clotting and possible heart failure. Also recipient runs the risk of infection from hepatitis or HIV pathogens. Excessive red blood cell production can be detected in blood tests. Or repo (recombinant erythropoietin cloned through genetic engineering) is a form of blood doping. repo mimics body s naturally occurring hormone EPO that stimulates red blood cell production. To increase oxygen transport. Thereby increasing aerobic capacity. repo has been widely used in endurance based activities such as the Tour De France. It carries a major risk of thrombosis and heart failure. Due to increased blood viscosity. Reduces resting heart rate to dangerously low levels during sleep. Reduces production of naturally occurring hormone EPO. Excessive red blood cell production can be detected in blood tests. 126
EXERCISE AND SPORT PHYSIOLOGY Or Gene doping is also used to enhance performance and is a form of blood doping. For example, repoxygen is designed as a viral gene delivery vector. And is injected into muscle to induce the syntheses of EPO in the muscle tissue. Which leads to increased production of red blood cells. Athletes would benefit because their genes would be altered to increase aerobic strength and endurance. Gene doping would carry risks of increased blood viscosity. Making pooling and clotting more likely. Putting increased stress on the heart. Causes dehydration during long events. Very difficult to detect you would need gene profile before and after use. 5) Discuss the use of legal ergogenic aids in their role of improving physical performance. In your answer explain the positive and negative effects of each aid you have chosen to write about. 20 marks Student note This is a very discriminating question as you have a number of aids to discuss. When planning your answer you should consider the broad categories of legal ergogenic aids that are introduced in the model answer below and give at least one example of an aid to support each category. You will not be expected to cover all the categories of legal ergogenic aids listed below. But when you select a category, aim to provide at least 5 solid points. 5 marks for definition and their role: An ergogenic aid is any substance or method, which enhances performance. Legal aids include any method used in training which has this effect. Including training equipment and environment, therapies, mechanical, nutritional and psychological aids. There is often a fine line between was is legal and what is illegal. And this decision is determined by World anti-doping agency (WADA). For example, consuming large quantities of caffeine used to be illegal, but the rules changed in 2002, when drinking large quantities of caffeine became legal again. This nutritional aid is used to promote fat metabolism, and spares glycogen reserves. And hence reduces adipose tissue. On the down side, caffeine produces a state of nervousness. Can disrupt sleeping patterns. And abrupt ceasing of caffeine intake can lead to severe headaches. 5 marks for nutritional ergogenic aids: The manipulation of an athlete s diet is a most effective method of enhancing performance. Carboloading is a method used to raise muscle glycogen stores above their resting levels. Prior to endurance competitions with over 90 minutes continuous activity. It relies on the principle of depleting and repleting muscle glycogen levels. Or maintaining a high intake of carbohydrate as a normal dietary intake. To elevate muscle and liver glycogen stores. And hence prolong the quality of performance beyond the 90 minute fatigue threshold. Disadvantages include a temporary increase in body weight. Since more water is needed to store the increased glycogen stores. And during the depletion phase many athletes feel weak, depressed and irritable. Hence the aim is to reduce the depletion phase to a minimum. There is a risk associated with using nutritional supplements due to the potential problem of contamination of the ingredients. (You could also discuss creatine supplementation and fluid intake - ergogenic aids included on your syllabus). Chapter 26 127
5) continued 2 marks for psychological ergogenic aids: Many athletes use imagery/hypnosis/visualisation to stimulate mental rehearsal of relevant skills. By activating neural pathways that reinforce skill. Many athletes use music via ipod to stimulate rhythm of an activity. Or to produce calmness prior to an activity requiring control at full effort. 3 marks for therapies: Physiotherapy/acupuncture/herbal medicines and cold therapies (cryotherapy) methods are used during recovery and injury prevention and treatment. Ice baths and ice belts are used to reduce joint and muscle inflammation, produced by microtears in stressed tissue. Ice baths are used to reduce muscle soreness (DOMS) and aid recovery of local damaged tissue. Ice/cooling jackets attempt to reduce core temperature in very hot conditions. For example, tennis players use cooling towels during long hot matches. Precautions should be taken because prolonged application at very low temperatures could have detrimental effects such as frost bite. 5 marks for mechanical aids: Mechanical aids include resistance training equipment such as weight training machines or pulley machines with stacks or hydraulic systems. Many of these aids are designed to mimic the sports movement. Which make the movement specific to the sport. For example, the swim ergometer operates on a pulley system and simulates swimming actions on land. This pulley provides the tools necessary to develop aerobic endurance and anaerobic power for swimming without getting wet. Swim ergometers are very expensive to buy. And so there are alternatives such as extendable latex tubes. Which can be used in a similar way. Towing sledges/parachutes increase resistance. A towing sledge is a training device, which includes a powder coated steel sledge and belt attached to a shoulder harness. The user is required to put add-on weights to the sledge. Sledge resistance training is thought to improve speed, acceleration and leg strength. However, it is thought to eliminate the important eccentric contraction phase on initial ground contact, prior to the concentric contraction phase. This may be a significant disadvantage in the context of improving the sprinter s ability at maximum speed. 5 marks for environmental ergogenic aids such as altitude training: Altitude presents a hypobaric environment that can have a notable physiological impact on endurance-based exercise performance. Endurance athletes use this ergogenic training aid in an attempt to improve sea-level performance. This is done by increased manufacture of red blood cells in response to living and training at a reduced atmospheric pressure. On initial ascent to altitude, the performer suffers from hypoxia (lack of oxygen). And physiological adaptations start to cope with the environment. Training intensities increase over the period of stay normally three weeks minimum is recommended. On return to sea level, the short-term additional oxygen carrying capacity of the blood improves the intensity and duration of aerobic activity in events such as a marathon race. Altitude training is expensive. And can disrupt family life and social relationships. 2 marks for conclusion: In conclusion, all these examples of legal ergogenic aids will assist performance. However, it is important that the use of such aids is carefully planned to optimise their effects. 128