Module 1 Strength and Conditioning for Sport Unit 1 Theoretical Aspects of Sports Training in Exercise and Fitness Energy Systems and Models of Training Robert Lynch BSc NCEFT Aims: To provide the students with a knowledge of the energy systems and models of training within the Strength and Conditioning Context. Objectives: To identify the various structures of the energy systems. Describe the effects of the energy systems on sports performance. Describe the models of training. Identify various considerations associated with Strength and Conditioning training and fatigue. 1 2 Assessment Module 1 Requirements Select a team or a small group of athletes from an individual sport and design conduct a S & C programme for that group. Module 2 Requirements Conduct an evaluation of a S & C programme that you have implemented with a visual presentation of one complete session. Who am I? Very Briefly: Name Educational Background Relevant work background Sport/Exercise History/Interests Where do I fit in? 3 4 1
For the Group Briefly analyse your assigned sport and analyse/discuss the energy system considerations associated with: Group 1 Long distance runner Group 2 100m sprinter Group 3 Rugby Player Group 4 Basketball Group 5 Shot put CEHF Revised: Workouts, training programmes and activities of daily living require different amounts of energy. Humans obtain energy from the food we ingest. The body can only use this food after it has been chemically broken down and absorbed into the bloodstream. In simple terms, Carbohydrates, Fats & proteins are broken down by our body to produce energy. 5 6 CEHF Revised: Energy: the capacity to do physical work Sources and Storage: Energy enters the body in the form of carbohydrates, fats and proteins (food). It is then converted into a fuel that can be used by the body. Carbohydrates are stored in the muscles, liver and blood in the form of glycogen Fats are stored as fatty acids in the adipose tissue and as triglycerides in the muscle Energy Systems and Exercise Science: Up until now Primary focus has been the use of fat as an energy source to regulate body weight. Now Strength and Conditioning Considerations: Its all about performance 7 8 2
Adenosine Triphosphate. (ATP) ATP Short Video: https://www.youtube.com/watch?v=bbtqf9q_pfw Adenosine Triphosphate. (ATP) Energy in the form of Adenosine Tri Phosphate (ATP) is the end product of food ingestion. ATP adenosine triphosphate fuels all muscle activity. ATP is a chemical structure made up of adenosine and three phosphate atoms. 9 10 Adenosine Triphosphate. (ATP) The high energy in the two bonds connecting the three phosphate atoms is released when the bonds are broken; it can be used for muscular contraction. ATP is stored in the myosin heads. Adenosine Triphosphate. (ATP) Due to its unstable nature, only enough ATP to complete a few seconds of muscular work can be stored. ATP must be continuously resynthesised (reformed) from adenosine diphosphate (ADP). 11 12 3
Adenosine Triphosphate. (ATP) Three sources in which ATP is resynthesised from: 1. Creatine Phosphate Immediate sources using stored energy. 2. Glycolosis Blood Glucose & Stored Glycogen. 3. Oxidative Metabolism Aerobic energy system Muscle Contraction & ATP Short Video: https://www.youtube.com/watch?v=h6okup uyby0 https://www.youtube.com/watch?v=0kfmbr RJq4w 13 14 Muscle Contraction & ATP Muscle contraction occurs with the interaction of protein filaments Actin and Myosin. Actin and Myosin drawn into one another by the movement and formation of cross-bridges. The proteins temporarily bind together and pull one another. Muscle Contraction & ATP Sliding Filament Theory https://www.youtube.com/watch?v=edhzky DxrKc 15 16 4
Muscle Contraction & ATP This activity, repeated many times down each filament of actin and myosin, and across all of the muscle, which might include millions of these protein filaments, results in the shortening of muscle and the creation of force. Muscle Contraction & ATP Movement of these cross-bridges require energy. Only one chemical, Adenosine Triphosphate (ATP) found stored in the myosin heads, is able to provide it fast enough and in sufficient quantity to maintain the formation and movement of crossbridges. 17 18 Muscle Contraction & ATP The ATP is only found in relatively small amounts Enough to fuel no more than one second of intense muscular effort. It is continually reformed (resynthesized) for almost all sporting activities. The energy for the resynthesis of ATP can come from three different sources, the three energy systems. Muscle Contraction & ATP ATP fuels all muscle activity and the energy for contraction comes from the breakdown of ATP to another chemical, Adenosine Diphosphate (ADP). Chemical reaction - One molecule of phosphate (P) splits from one molecule of ATP to leave one molecule of ADP. A relatively large amount of energy is released which is then used by actin and myosin to bring about the contraction. 19 20 5
Muscle Contraction & ATP Muscle Contraction & ATP Turn to page 8 21 22 Anaerobic Energy Systems: Intensity of effort increases above resting levels. At some point not all of the energy required to resynthesize ATP can be provided from fats and carbohydrate broken down in the presence of oxygen Anaerobic Threshold. Variations occur due to individual and training differences. 23 24 6
Anaerobic Energy Systems: Shortfall in energy has to be met from one of the two anaerobic processes: 1. Phosphagen energy system. 2. Lactate energy system. Phosphagen Energy Systems: Source of energy Breakdown of phosphocreatine (creatine phosphate). Provides small amount of energy, Enough for ten seconds (approx) of maximal effort. Released quickly to provide explosive movements or bursts of activity team games. 25 26 Phosphagen Energy Systems: Reduced intensity/stop-start sports may increase duration of movement (e.g. in racket game rallies). Very susceptible to training up to 300% more phosphocreatine in store after training. Training effects are short-lived and therefore must be maintained during the competitive season. Phosphagen Energy Systems: Use of Creatine prominent in athletes attempting to improve performance. Limited research available on the effectiveness on performance. With appropriate rest, Phosphagen stores are half-recovered in thirty seconds and fully recovered in five minutes. Repeated short sprints are possible 100m sprinters can run a number of heats on the same day & quality performances. 27 28 7
Phosphagen Energy Systems: Phosphagen Energy Systems: Training implications: System must be overloaded Rest interval no more than thirty seconds between repetitive runs to fully stimulate. Recovery essential to maintain quality at least five minutes from time to time to refuel the phosphagen stores fully. 29 30 Named after the end product of the breakdown of the fuel used (glycogen) lactic acid. Also known as anaerobic glycolysis - glycogen break down (glycolysis), when there is a shortage of oxygen. Lactic acid production interferes with the chemical reactions inhibiting cellular functions until the excess acidity can be removed. Examples Page 10 31 32 8
Training of the appropriate type can improve performance by: 1. Increasing the lactic acid tolerance of the muscle (greater concentrations can be endured before contraction cease). 2. Improving the ability to remove lactic acid from the working muscles. Lactic acid is produced because the muscle is working at a level where the force produced by the aerobic slow twitch fibres (ST) is not enough. The point at which the anaerobic fast twitch fibres (FT) have to be recruited varies between individuals, because it depends upon the relative percentages of ST and FT fibres in the muscles (a genetic factor). 33 34 Muscle Fibre Types Performers with a high percentage of ST fibres will be able to work at a greater intensity before building up large quantities of lactic acid but their maximum work intensity will be quite low because they have fewer FT fibres to call upon thereafter. 35 36 9
Performers with a high percentage of FT fibres will start to build up lactate at lower work intensities but have the potential for higher maximum work intensity because many more FT fibres can be called upon. However, this type of performer will fatigue sooner. Consequently, the good endurance performer who has plenty of ST fibres can sustain a higher steady pace than the sprinter but the sprinter can produce a faster maximum speed. Performers with a high percentage of FT fibres will start to build up lactate at lower work intensities but have the potential for higher maximum work intensity because many more FT fibres can be called upon. However, this type of performer will fatigue sooner. Consequently, the good endurance performer who has plenty of ST fibres can sustain a higher steady pace than the sprinter but the sprinter can produce a faster maximum speed. 37 38 Ft fibres use the same fuel (glycogen) as ST fibres. Specialist ability to contract rapidly causes restriction. Glycogen is broken down as far as pyruvic acid to release energy for contraction but the aerobic pathway is not open because FT fibres lack ability to use oxygen. Pyruvic acid converted into lactic acid and this accumulates until the muscle cell no longer contract. This may take 30-40 seconds in the untrained but it is very responsive to training. 39 40 10
Challenges for Anaerobic Athletes: Balancing lactic acid production and removal. Very little can be done about the production of lactic acid because - same in the trained and untrained for the same level of work. Training improves the ability to tolerate larger amounts of lactic acid. Mixed research suggesting physiological improvement in the muscle and psychological to pain. Challenges for Anaerobic Athletes: Most significant improvement is in the ability to remove lactic acid. Although some lactic acid can be recycled within its own cell because there is some aerobic capacity in all FT fibres, the majority passes out of the cell. Some of this is processed in neighbouring ST fibres but most moves into the bloodstream. 41 42 Challenges for Anaerobic Athletes: Chemicals in the blood, producing carbon dioxide, which is breathed out, can remove further lactic acid and much of the rest is transported either to other muscle tissue or organs such as the liver and heart. Challenges for Anaerobic Athletes: It is important to maintain good blood flow through working muscles after the major effort has ceased. This emphasises the importance of cooling down. Dynamics of some sports inhibit this process Boxing example. What other sports interfere with this? 43 44 11
Lactate Energy Systems Aerobic Energy Systems: Sport/Activity Duration of Anaerobic Phase Typical Follow-on Activity Better Follow-on Activity Short Video: Hurling Basketball 10-30 second bouts of activity 6-10 Seconds of intense sprinting 1-2minutes of standing or walking Standing during dead ball Walking or standing on toes ready to move Walking or moving in new position https://www.youtube.com/watch?v=pqmsjsme 780 Volleyball Repeated 15-30 second rallies Substituted - sit down Keep moving for few minutes Rugby forward 30 second ruck/maul Stand when whistle blows Avoid standing still Your sport: 45 46 Aerobic Energy Systems: In any activity, which is sustained for a period of time (e.g. running, cycling or swimming), there must be sufficient oxygen present to provide all of the energy requirements; otherwise the performer would slow down. This is true of all endurance sports. Aerobic Energy Systems: Endurance athletes must be able to judge precisely the point where additional energy from anaerobic processes is required while also working just below this threshold. The athlete is able to work at the highest possible speed without developing fatigue from a build-up of lactic acid in the muscle. 47 48 12
Aerobic Energy Systems: Onset of anaerobic glycloysis varies between individuals Can be pecific to the type of activity running and cycling. It is highly trainable and therefore the endurance performer should devote a considerable amount of training time to pushing back this anaerobic threshold. Aerobic Energy Systems: Anaerobic energy is not only important to endurance performers. Field games - multi-sprint sports; considerable demand is placed upon aerobic energy because many of the movements are sustained at a high level. Even in activities that are essentially anaerobic (e.g. 400 metre running), aerobic training is crucial. Well developed aerobic system helps to delay the onset of lactic acid accumulation in 49 50 Aerobic Energy Systems: Benefits also apply to the phosphagen athletes (the power performer such as the thrower, jumper or sprinter). The high intensity training of this anaerobic performer will only be of value if it stresses the working muscles. The Predominant Energy Systems for Selected Sports % ATP contribution by energy system SPORT ATP-PC Glycolysis Aerobic Baseball 80 15 5 Basketball 80 10 10 Field Hockey 60 20 20 Football 90 10 - Ice Hockey: Forwards/Defence Goalie Soccer: Goalie/Wings/Striker Halfbacks 80 95 80 60 20 20-20 Rugby 50 30 20 Gaelic Football 50 20 30 Volleyball 85 10 5 20 5 - - 51 52 13
Aerobic Energy Systems: Aerobic energy system is dependent upon the supply of oxygen by the oxygen transport system. Oxygen arriving at the muscle is picked up by myoglobin and transported to the mitochondria where aerobic glycolysis takes place. In anaerobic glycolysis, glycogen is broken down to pyruvic acid, and this still occurs when oxygen is present. Aerobic Energy Systems: The presence of oxygen ensures that pyruvic acid does not degrade into lactic acid. Pyruvic acid is converted to a substance called acetyl co-enzyme A. The co-enzyme enters a complex series of chemical reactions called the Krebs cycle. When you burn fat, as you do in low intensity work, the fat is broken down to acetyl coenzyme A and then follows the same pathway. 53 54 Aerobic Energy Systems: The Krebs cycle releases its energy relatively slowly aerobic glycolysis cannot support very high intensity work, but it does so in abundance. Anaerobic glycolysis will only release enough energy from one molecule of glycogen to resynthesize 3ATP, aerobic glycolysis provides energy to resynthesize 38ATP from one molecule of glycolysis for about 60-90 minutes In poorly trained athletes - ensure that as much of it as possible is used aerobically. Aerobic Energy Systems: Running a race at varying pace, will fatigue more quickly than the steady-pace runner. Training has beneficial effects: Glycogen stores can be increased as much as threefold. A well-trained endurance athlete can spare the use of glycogen by burning a greater percentage of fat. 55 56 14
Oxygen Consumption during Aerobic exercise Oxygen Consumption during Anaerobic exercise 57 58 Contribution of each Energy System Nearly every muscle contraction involves a contribution from each of the three systems. Think of the contribution of the three energy systems in terms of the duration of the event: If the event lasts for only a few seconds - ATP = phosphagen system. An event lasting a minute (e.g. 400 metre hurdles) - anaerobic glycolysis & aerobic glycolysis. More than about three minutes depending upon fitness and individual differences - from aerobic glycolysis. Role of Energy Systems in Programme Planning In most cases, although all energy systems are switched on, one or two energy systems will predominate depending on the intensity and duration of the activity, together with the fitness level of the individual. Considerations Available Fuel (diet & glycogen stores) Work/Rest intervals Muscle Fatigue Intensity & duration of the session Rest/recovery/repair Individual Muscle Fibre Types 59 60 15
Role of Energy Systems in Programme Planning Group Work: Very briefly plan an exercise session for your assigned sports taking the energy systems in use into consideration: Group 1 Long distance runner Group 2 100m sprinter Group 3 Rugby Player Group 4 Basketball Group 5 Shot put Vo2 Max Overview: The most frequently requested test procedure in exercise physiology. Coaches frequently discuss their athletes and the merits of their current VO2max. The popularity of the Vo2max test would suggest that many people in the sporting community believe it to be the single best predictor of athletic ability. But what does it mean and what relevance does it have in the context of training and performance? 61 62 Vo2 Max Vo2 Max What is VO2max? Vo2 max is the maximum rate of oxygen that can be utilised by the body during exercise. The assumption behind the test is that the greater the rate of oxygen consumption the better an individual s aerobic fitness. A higher figure would therefore imply a greater level of endurance conditioning. In theory then it should be possible to categorise athletes, in terms of VO2max, according to the aerobic demands of their particular sport. Interpreting VO2max Data High VO2max - prerequisite to success in sports with a strong aerobic component. Research within endurance athletes suggests that VO2max is only a modest predictor of performance. Other factors in addition to a high VO2max such as: Ability to sustain prolonged activity at a high percentage of VO2max (referred to as fractional utilisation) Improved economy of effort defined as the steady state oxygen consumption of standardised exercise intensity. 63 64 16
Vo2 Max Does VO2max Reflect Training Status? Limitations of VO2max in endurance performance: High genetic influence on aerobic capacity. After 3-5 years of senior training, the elite athlete fails to show any further increase in their VO2max despite further improvements in their endurance performance. Ability to work at a high percent of maximal work capacity has been shown to improve. Research suggests that the lactate threshold is a better predictor of endurance performance than VO2max because it represents the maximum steady state pace that can be sustained for a prolonged period of time. Factors Affecting Performance Fatigue: Fatigue is defined as an inability to maintain a power output or force during repeated muscle contractions. 65 66 Factors Affecting Performance Possible Fatigue Mechanisms (Weak Links) Possible Fatigue Mechanisms Psyche /brain Impaired: Motivation i.e. motor unit recruitment Spinal cord Reflex drive Peripheral nerve Neuromuscular transmission Muscle sarcolemma Muscle action potential Transverse tubular system K +, Na + Excitation Ca ++ release Activation Energy supply Actin-myosin interaction Factors Affecting Performance Possible Fatigue Mechanisms (Weak Links) Central Fatigue Central Nervous System. Peripheral Fatigue Peripheral factors such as neural, mechanical or energetic events. Neural Factors Failure at neuromuscular junction, sacrolemma and trasverse tubules. Neuromuscular Junction Research suggests it is not a site of fatigue. Sacrolemma and Trasverse tubules Research suggests a possible site of fatigue. Mechanical Factors Cross bridge & availability of ATP Cross-bridge tension + heat Force/Power output 67 68 17
Factors Affecting Performance Energetics of Contraction Fatigue - simple imbalance between the ATP requirements of a muscle, and its ATP-generating capacity. When exercise begins and the need for ATP accelerates, a series of ATP-generating reactions occur to replenish the ATP. As the cross-bridges use the ATP and generate the ADP, creatine phosphate provides for the immediate resynthesis of the ATP (CP + ADP ATP +C). As the creatine phosphate becomes depleted, ADP begins to accumulate and the myokinase reaction occurs to generate ATP (ADO + ADP ATP +AMP). The accumulation of all these products stimulates glycolysis to generate additional ATP, which may result in a H+ accumulation. Factors Affecting Performance Energetics of Contraction As ATP demand continues to exceed supply, a variety of reactions occur in the cell that limit work and may protect the cell from damage. Remember that ATP is needed to pump ions and maintain cell structure. In this sense, fatigue serves a protective function. 69 70 Factors Affecting Performance Order of Muscle Fibre type recruited and exercise yp intensity Factors Affecting Performance Ultra Short-term Performances < 10 Secs Shot put, long jump, 50 100 metre sprints. Require large amounts of energy in short time frames (Power orientated). All muscle fibres are involved. Fueled by ATP CP sytem 71 72 18
Factors Affecting Performance Short term performances: 10 180 Secs Maximal performances 10 60 Secs: 70% Anaerobic Once extended to minutes 60% from slower aerobic Factors Affecting Performance Factors Limiting all out aerobic performance: Moderate Length Performances (3 20 minutes) 60% ATP derived from aerobic process in the first three minutes. This increases to 90% for remainder. 73 74 Factors Affecting Performance Intermediate Length Performances: 21 60 Minutes Factors Affecting Performance Long Term Performance: 1 4 Hours 75 76 19
Relationship Between Training and Fatigue Fleck (1999) summarizes training as a systematic and scientific process by means of physical exercise that is conducive to performance. Periodised training refers to varying the training programme at regular intervals in an attempt to bring about optimal gains in strength, power, endurance, speed and motor performance. The aim of sports training is to prepare the body through different training loads for competition, while at the same time minimizing the risk of injury, illness and fatigue in the period leading up to competition. Relationship Between Training and Fatigue Training for success has increasingly become a balance between achieving peak performance and avoiding the negative consequences of overtraining. The relationship between optimal performance, physical adaptation, and the exhaustive-recovery processes under different types of loading was researched in the 1950 s by Yakovlev (1955) based upon earlier Russian concepts of adaptation of current adaptive reserves. 77 78 Relationship Between Training and Fatigue Increasing Intensity, Duration and Frequency of Training Models of Training Single Factor Model of Training (Super Compensation) After applying load exercises in training, the body experiences fatigue. During the rest period biological stress are not only replenished but they exceed normal levels. The body compensates fully followed by a rebounding or supercompensation cycle, when a higher adaptation occurs followed by a functional increase in performance 79 80 20
Models of Training Models of Training Single Factor Model of Training (Super Compensation) Single Factor Model of Training (Super Compensation) Positive overtraining: for eliciting gains in performance after long intervals between training stimuli. The improvement rate is higher when athletes participate in more frequent training sessions if the sessions are not so frequent that they prevent the supercompensation phase. 81 82 Models of Training Single Factor Model of Training (Super Compensation) Maintenance training to remain at a certain level of performance. Undertraining when the stress is insufficient to maintain performance. Negative overtraining: when the stress decreased the performance. Models of Training Single Factor Model of Training (Super Compensation) 83 84 21
Models of Training Two Factor Model of Training Model implicates the super imposed after effects of the two processes of fitness adaptation and fatigue. Fitness after effect decaying at a slower rate than the fatigue after effect. Greater focus on overreaching. The model proposes the overlapping of the following effects: Long term after effect emphasising peak performance. Short after effect developing fatigue Models of Training Two Factor Model of Training 85 86 Optimising Recovery Recovery an essential concept in training. Athletes continue to train longer and harder to achieve performance. The process of restoring muscles and key physiological processes stressed in an activity. Influenced by various factors such as: Athlete s age Experience Gender Environmental Factors Muscle Fibres Nutrition 87 Optimising Recovery Methods for reducing staleness: 1. Recovery must be matched with the specific stress or stressors. 2. Training must be directed at improving specific capacities which will in turn increase the specific (matched) stress tolerance. 3. Psychological and social stressors must be minimised to better utilise the available resource of stress tolerance for adapting to the psychological stress. 88 22
Summary Identified the various structures of the energy systems. Described the effects of the energy systems on sports performance. Questions? Described the models of training. Identified various considerations associated with Strength and Conditioning training and fatigue. 89 90 23