Nutrition Periodization for Athletes : Taking Traditional Sports Nutrition to the Next Level (eBook)

1 Energy Systems andPhysical Periodization It may seem odd to begin a sports nutrition book with discussionsof energy systems and the concept of physical periodization,but both of them provide a staple in your foundationalknowledge of understanding how to use and change your nutritionthroughout your training. By knowing about the variousenergy systems in your body that are called upon during differenttypes of exercise, you will have a much better idea of whichnutrients are being used and which are not in your trainingsessions. If you do not have a clear idea of your physical goalsassociated with each training cycle, you miss the opportunitiesto implement specific nutrition strategies that optimize yourhealth and performance. ENERGY SYSTEMS The body's three energy systems that provide you with the energyto fuel your training sessions-from warm-ups to sprints tostrength training to long endurance training-are the phosphagensystem, the glycolytic system, and the aerobic pathway. These systemsare engaged at different times and in different amounts basedon the intensity and duration of training. Warm-ups exert a much different metabolic response and energy system demand on thebody than does sprinting. Strength and power training aresomewhat different than long endurance training. It is these alterationsin training load (volume and intensity) that dictate what,when, and how your energy systems contribute to fueling yourworkouts. The carbohydrates, protein, and fat that you eat on adaily basis and store in your body follow different metabolicpaths, and their utilization depends on the intensity and durationof your training. The phosphagen system, also known as the phosphocreatineor creatine phosphate system, is an anaerobic (without oxygen)pathway that supplies immediate energy to your working muscles.The amount of phosphocreatine stored in your body is limited, sothis system only provides you enough energy for about 10 secondsof high-intensity exercise. Many sprint and explosive power athletesutilize this system. After the initial 10 seconds of this type oftraining, athletes typically require about 2-4 minutes of rest toallow regeneration of the phosphocreatine used. It is very importantfor athletes participating in this type of training to allow thisrest interval between sets to allow the energy system to recoveryduring this maximal energy use. The glycolytic system, also known as glycolysis, is anotheranaerobic metabolic pathway that functions to break down glucoseor glycogen to energy. As with the first energy system, theglycolytic system also has limited stores and provides onlyenough fuel for about 1-2 minutes of high-intensity exercise.This system also yields lactate molecules, which can be thoughtof as friends rather than foes. Lactate can be used as an energysource to fuel your muscles at certain intensity levels. The third energy system, aerobic energy, uses oxygen to provideenergy and can thus produce a larger amount of energy.Pyruvate, a product of glycolysis, enters the mitochondria (theenergy factories of the cell) and generates a constant supply ofenergy to fuel working muscles for hours and hours.