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Chapter

Cover The Biochemical Basis of Sports Performance

Adaptations to training  

This chapter reflects on the principles of training to improve performance in sport. The level of success that an individual can achieve is limited by their genetic potential, and this sets an upper ceiling to performance. To reach that potential, however, requires a sustained period of intensive training, at least for most athletes. Despite the tendency for athletes to attempt to copy the details of the training programmes of their sporting heroes, this is seldom successful. This is in part because of a lack of the physiological, biochemical, and psychological characteristics that are prerequisites for success, but also in part because there is a great variation between individuals in their trainability. Indeed, the type of training—and the frequency, intensity, and duration of training sessions—will vary greatly between sports, and will also be different for different individuals. The chapter then considers the danger of developing an overtraining syndrome.

Chapter

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Biochemical Bases for Performance  

This chapter discusses adenosine triphosphate (ATP), which is the donor of the free energy that is used for muscle contraction, for the supporting ionic pumps that regulate muscle electrical activity, and for biosynthesis. It also talks about the molecule of ATP that is made up of a molecule of adenosine and consists of a purine base, a five-carbon sugar, and a chain of three phosphate groups. It also analyszes the phosphate groups that are attached by what are known as high-energy bonds, which means that considerable energy is required to produce the attaching reaction. The chapter points out that the formation of the high-energy bond is known as phosphorylation, while the breaking of the bond is known as hydrolysis. It details how adenosine diphosphate (ADP) is formed when a molecule of ATP is hydrolyzed and loses one of its phosphate groups.

Book

Cover The Biochemical Basis of Sports Performance

Ronald J. Maughan and Michael Gleeson

The Biochemical Basis of Sports Performance looks at this topic by type of sport. Firstly, however, it introduces with an assessment of the biochemical basis of exercise and sport. The first sport it tackles is weightlifting, for which muscle strength and function are vital. It looks at protein in enzymes and the nutritional effects on strength training and performance. Next, it turns to the sprinter, for whom anaerobic metabolism is important. Then, it looks at middle-distance events and talks the reader through the glycolytic pathway amongst other elements. After that comes the endurance athlete who needs to consider energy supply and aerobic power. The game player follows and here fatigue in sprint sports is looked into. The text then moves on to a more general discussion of what constitutes sporting talent. It ends with a look at adaptations to training: training for speed, strength, middle-distance, endurance, and training strategies.

Chapter

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Cardiorespiratory Bases for Performance  

This chapter provides a background on cardiovascular and respiratory systems from the perspective of the athlete. Their most important function is to deliver oxygen to the exercising muscles and to remove carbon dioxide, while maintaining blood flow to vital organs. The chapter explains how the cardiovascular system matches the blood flow to skeletal muscle to its metabolic rate. It also analyszes two circuits of the cardiovascular system that are arranged both in parallel and in series: pulmonary circuit and systemic circuit. The chapter explains that the pulmonary circuit conducts blood from the right side of the heart to the lungs and back to the left side of the heart. It clarifies how the systemic circuit conducts blood from the left side of the heart to all the tissues in the body and back to the right side of the heart.

Chapter

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The endurance athlete  

This chapter assesses the energy and oxygen cost of prolonged submaximal exercise, looking at the endurance athlete. Based on the physiological and biochemical demands of the events, the runners' distinction between middle-distance and long distance is a realistic one. At the longer distances, lasting about thirty minutes or more, anaerobic metabolism plays only a small role in energy supply. In the longer events, successful performers are characterized by a high capacity to use fat as a fuel. This requires a highly developed cardiovascular system to supply oxygen to the working muscles and a high activity in the muscles of the enzymes involved in oxidative metabolism. The chapter then considers fat oxidation, the metabolism of pyruvate derived from glycolysis, and the mechanisms of fatigue in prolonged submaximal exercise.

Chapter

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The games player  

This chapter addresses the activity patterns and work rate in team games. Games such as football, soccer, rugby, hockey, and tennis involve repetitive bouts of high-intensity exercise. Maintaining performance for the full duration of matches is obviously important to success and depends to a large degree on the ability of muscle to recover from the last exercise bout. Compared with continuous exercise activities such as running and cycling, relatively little attention has been directed to the metabolic responses to team games. However, some standardized models of intermittent exercise have been developed in recent years. The chapter describes how these protocols, as well as measurements made during competition itself, have shed some light on the demands of participation on the skeletal muscle recovery processes after intense exercise and their importance for metabolism and performance during one or more subsequent exercise bouts.

Chapter

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Introduction to Training for High Performance  

This chapter discusses the quality of an athlete's performance as the result of a complex blend of many factors that determines the athlete's potential to excel, is his or herwith a major factor being genetic endowment. It mentions body size, cardiovascular traits, proportions of muscle-fiber types, and gross motor coordination as factors that are genetically predetermined. It also emphasizes the most important factor affecting athletic performance, which is the amount and suitability of the training that precedes the competition. The chapter defines training as the stimulation of biological adaptations that result in an improvement in performance in a given task. It focuses on determining the most effective stimulus to exploit the body's ability to adapt to potentially harmful stimuli in order to effect biological changes that will improve performance.

Chapter

Cover The Biochemical Basis of Sports Performance

Introduction: The biochemical basis of exercise and sport  

This introductory chapter provides an overview of the biochemical basis of exercise and sport. All sports activities involve muscular activity, and for each one of us there is an upper limit to our ability to perform any task involving muscular effort. It is these differences in physical capacity between individuals that form the basis of sporting contests as each competitor strives to reach those limits. Understanding the body's responses to exercise is thus important for the athlete who seeks to perform well, but it is also a crucial element in the development of successful physical activity programmes that can tackle the growing prevalence of the diseases that accompany a sedentary lifestyle. The chapter then describes some of the factors that have contributed to the improvement of world records in sports events over the last century. It also looks at the use of performance enhancing drugs by some athletes.

Chapter

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Middle-distance events  

This chapter evaluates the relative contributions to energy metabolism from phosphocreatine breakdown, anaerobic glycolysis, and carbohydrate oxidation during middle-distance running. Oxidative metabolism makes the major contribution to energy production when the exercise duration exceeds about one to two minutes. However, at least for exercise intensities that can be sustained for less than about ten minutes, the rate at which energy must be supplied to the working muscles exceeds the maximum rate of the oxidative processes. The chapter uses the example of the middle-distance track runner to describe the metabolic processes occurring and to consider the causes of fatigue and potential limitations to performance in events taking place over this time scale. The chapter then looks at the glycolytic pathway and the regulation of glycolysis.

Chapter

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Muscle Physiology  

This chapter focuses on muscle physiology. It considers how muscles are controlled by the nervous system and how the nervous system and muscles work together to produce what are commonly called strength and power performance. It also demonstrates the ability of muscles to generate force and power and the ability of the nervous system to activate the muscles appropriately for a given task in which performance depended. The chapter describes the composition of muscles of cells called muscle-fibers, which range in thickness from about 50-100 μm and in length from a few to several millimeteres. It refers to myofibrils that make up about 85% of the contents of a muscle-fiber, while the remaining 15% are largely composed of sarcoplasmic reticulum (SR), mitochondria, glycogen granules, and fat droplets.

Chapter

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Neuromuscular Bases for Performance  

This chapter explains how the nervous system controls muscle contraction as reflected in the activation of motor units. It focuses on exercise-induced fatigue and its effects on neural and muscle function and considers factors such as muscle size and muscle temperature that affect strength, power, and speed performance. It also mentions the motor unit, which is the common pathway for muscle control wherein several parts of the brain and spinal reflexes control the force of muscle contraction. The chapter talks about motoneurons, which consists of a neuronal cell body situated in the ventral horn of the spinal cord or within nuclei of the brain stem. It refers to dendrites that extend from the soma and a motor axon that extends from the soma, which is part of a motor nerve serving a muscle.

Chapter

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Other Considerations  

This chapter looks at blood glucose, which is the primary energy source for cells in the brain and the central nervous system and the only energy source for red blood cells. It details how an hour of heavy continuous exercise training, competing in a team sport, or a 30-second sprint-training intervals can reduce muscle glycogen concentration by more than 60%. It also examines carbohydrates that are converted by digestive enzymes to the six-carbon sugar, glucose, before they enter the glycolytic pathway or be stored as glycogen. The chapter talks about nutritionists that have derived a numerical scale known as the glycemic index (GI), a numerical scale developed by nutritionists which rates various foods by how quickly and to what extent they increase blood glucose. It refers to international competitions wherein athletes must travel by air across a number of time zones to participate.

Chapter

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Peaking, Tapering, and Overtraining  

This chapter focuses on training given on a set of physiological adaptations, wherein training stimulus is reduced once maximal adaptation has occurred and a different form of training is introduced. It explains how peaking occurs when an athlete completes a training program incorporating the correct sequencing of different forms of training. It also defines overtraining as the condition that arises when the magnitude of the training stimulus chronically exceeds the athlete's capacity to adapt to it. The chapter talks about the suppressive effect of overtraining on certain components of the immune system. This makes the athlete less resistant to infection and common illnesses, such as upper-respiratory-tract infections (URTI). It explains how the recognition of the early indications that an athlete may be approaching the overtrained state is a major challenge for a coach.

Book

Cover The Physiology of Training for High Performance

Duncan MacDougall and Digby Sale

The Physiology of Training for High Performance consists of three parts. Part I, which is about the physiological bases for athletic training, starts off with an introduction to training for high performance. It moves on to look at the biochemical bases and cardiorespiratory bases for performance. It looks at muscle physiology and then finishes with the neuromuscular bases for performance. Part II covers training for different sports and activities. It looks at endurance sports, anaerobic events, team sports, as well asnd training for power, strength, and speed as well. The last part, which presents additional factors affecting performance, looks at peaking, tapering, and overtraining; stretching and flexibility, and, finally, some other considerations, including nutrition, testing, altitude, and para-athletics.

Chapter

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Sporting talent: the genetic basis of athletic capability  

This chapter explores the different factors that can determine success in sport. These include motivation, appropriate training, nutrition, and tactics. However, perhaps the most important factor is raw talent in terms of the body's phenotype; in other words, the body's physical, physiological, and metabolic characteristics. These characteristics, which in terms of athletic capability might be taken to include muscle fibre-type composition, the size of the heart and lungs, body height and mass, etc., are all to a large extent determined by the genotype (or genetic endowment) of the individual. The chapter then looks at the structure and composition of the genetic material (DNA) and the principles of heredity. It also considers the possibility of gene doping.

Chapter

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The sprinter  

This chapter examines anaerobic metabolism. The sprinter has to sustain a very high-power output over a relatively short period of time. As the intramuscular supply of adenosine triphosphate (ATP) is sufficient to last only about two seconds, there is a pressing need to resynthesize ATP extremely quickly, and this is achieved by the breakdown of intramuscular stores of phosphocreatine and the rapid activation of glycolysis. Both of these processes occur without the utilization of oxygen; that is, they are anaerobic means of regenerating ATP. However, sprinting is not entirely anaerobic. There is a contribution of carbohydrate oxidation to ATP resynthesis during sprinting that increases as the duration and distance of the sprint increases. The chapter then describes the concept of the cellular energy charge and explains why there is a loss of adenine nucleotides during very high-intensity exercise.

Chapter

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Stretching and Flexibility  

This chapter discusses muscle stretching exercises performed by most athletes, which make up part of their warm-up before training sessions and competition. It analyszes regular stretch training that athletes do to increase their flexibility, which can be defined as the maximum range of movement achievable without injury at a joint or series of joints. It also talks about a high level of flexibility that is important in many types of performance. The chapter reviews issues of whether pre-activity stretching prevents injury or enhances or hinders performance and highlights be methods of flexibility training. It considers the different types of stretching and their effect on the muscle-tendon unit.

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Training for Anaerobic Events and Team Sports  

This chapter reviews a wide range of sports that require maximal efforts over a period as brief as two seconds or less or as long as two minutes. It looks at the relative contribution of energy-delivery pathways that depends upon the duration of the event. It also analyszes explosive events such as throwing, jumping, or weightlifting, which require maximal power output over only a few seconds and are derived from resting muscle stores of adenosine triphosphate (ATP) and from hydrolysis of phosphocreatine (PCr). The chapter illustrates team sports that typically require bursts of maximal effort separated by lower-intensity intervals or stoppages in play for rule infractions. It mentions ice hockey or soccer, wherein the intense activity may be sustained for up to 60 seconds without a stoppage in play or a slowing in tempo.

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Training for Endurance Sports  

This chapter reviews the replenishment of high-energy phosphate stores and the removal of lactate and H+ following bursts of high-intensity activity that occur through oxidative processes. It describes how endurance-trained athletes are able to recover more quickly after brief maximal intensity efforts than sprint-trained athletes. It also analyszes the pattern of team sports, which consists of brief bursts of maximal sprint-type efforts followed by lower-intensity recovery intervals. The chapter assesses key variables that must be considered when designing a training program for an athlete in a given sport, which include the intensity of the training stimulus, the duration of the training stimulus, and the optimal amount of recovery time following each training session. It details training for endurance sports, wherein intensity is conventionally quantified relative to the athlete's maximal aerobic power.

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Training for Strength, Power, and Speed  

This chapter discusses training principles that increase performance by stimulating both muscular and neural adaptations. It examines the role of specificity in adaptations and its importance in the design of training programs and highlights training that results in an increase in the muscle cross-sectional area (CSA) and strength. It also explores muscle-fiber hypertrophy that increased muscle size, which is primarily the result of increased muscle-fiber size that is expressed as fiber area. The chapter points out that the main contributor to increased fiber size is an increase in the size and number of myofibrils. It refers to the increase in the number of filaments and the number of myosin cross-bridges in cross-section that results in increased force-generating capacity.