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Training the Track & Field Athlete Through the Energy Systems

 

By Jack Ransone, Ph.D., Associate Professor of Human Performance
Oklahoma State University
USATF Coaching Education Level II and Level III Instructor

 

In track and field, as in many other sports, theorist and practitioners reside in different camps with inadequate communications. The blame rests with all of us. Coaches are responsible for the effectiveness of their training methods. New techniques allowed to remain in the minds of scientists or on silent pages in trade journals do nothing for the leaders of track and field.

American athletes, if trained correctly, are invincible. Our societal system is second to none in producing motivated, aggressive and self-asserted young men and women. Our scientific establishment is totally superior in human, as well as material sources, in its capacity to find quick answers to pressing problems. A carefully planned meeting of these two institutions will one day produce the greatest athletes the world has ever seen. We need to establish a system that is already present in many countries of the world--A coordinated mechanism of immediate dissemination of new information from the laboratory to the track, and a trusting relationship between the coach and scientist. Such a goal remains, as yet, a distant ideal in this country I will address many of those topics that remain lost in the halls of science.

There is no secret or mystery about the energy systems and their effectiveness when clearly understood. Track and field coaches must understand the energy system capabilities and limitations to design sequenced training programs. In teaching athletes to listen to their bodies during training sessions, adjustments can be furnished in the sequenced workout with careful understanding of the energy system. It is my intention to provide the coach with a workout training system based on accurate scientific knowledge as it relates to the energy systems.

Adenosine Triphosphate, or simply, ATP, is the immediate usable form of chemical energy for muscular activity. This is one of the most important of the "energy rich" compounds which is stored in all cells, particularly muscle cells. All forms of chemical energy available from the food we eat must eventually be transferred into ATP form before they can be utilized by the muscle cell. The amount of ATP in the muscle cell is limited and could be depleted in 1-2 seconds unless recharged to maintain muscular activity, thus, immediate synthesis of ATP is necessary. ATP supplies must be kept at peak concentration and must never fall below 60% of its resting levels for muscular activity to continue. The three systems of metabolic pathways available to replace ATP concentrations are: 1) Anaerobic Phosphagen (ATP-PC) Energy System, 2) Anaerobic Lactate (Glycolytic) Energy System and 3) Aerobic Energy System.

An energy rich compound called Creatine Phosphate (CP) is present in the muscle cell. This compound is used for the immediate resynthesis of ATP following high intensity exercise. The amount of ATP that can be resynthesized can last for 4 to 5 seconds. Remember, the 1 to 2 second supply from ATP stores, so collectively, you have about 5 to 7 seconds of ATP production. This system is referred to as the Anaerobic Phosphagen Energy System with no oxygen used to produce energy. To challenge this system, high intensity, workouts of 4 to 7 seconds are necessary. For example, 30 to 50 meters of maximal sprinting or 3 to 5 repetition-sets of weightlifting.

High intensity work (Sprints) involves moving the limbs at the highest possible velocity. More specifically, it involves the selective recruitment of motor unit pathways to improve the efficiency and firing of correct motor units that are available depending on the TYPE, INTENSITY, and DURATION of work executed. This motor learning must be rehearsed (practiced) at high speeds to develop and implant the complex recruitment for synchronized firing of these motor units. Points that must be followed in the training sessions: 1) the speed component of anaerobic metabolism should be trained when no fatigue is present, 2) most athletes require 24 to 36 hours of rest with low intensity work before doing maximum speed work again, 3) work sets of around 3-4 repetitions with 2-3 minutes recovery between repetitions, and 8-10 minutes recovery between sets is recommended for maximum results to occur, 4) the time period necessary for the proper resynthesis of ATP and CP recovery rates for CP resynthesis and 5) four (4) sets, involving 600 meters (ie. 4x4x65m) in total distance in a practice session is sufficient to stimulate this system.

The demand for energy (ATP) dictates which energy system will be challenged. The muscle will adjust to the necessary energy system. To challenge the lactate (glycolytic) system, the breakdown of glucose or glycogen anaerobically produces energy plus lactate and hydrogen ions (H+). When the demand for energy exceeds the body's ability to produce energy with oxygen, the muscle will become acidic. The presence of hydrogen ions, not lactate, makes the muscle acidic which will eventually shut down the system. For each lactate formed, one corresponding hydrogen ion is formed. This system operates in the muscle cell and its chemical reaction is: GLUCOSE + Pi + ADP + ATP + LACTATE + H+.

The formation of lactate is not necessary for the delivery of energy, but it serves as a storehouse for the hydrogen, and thereby, keeps the reaction going. Under anaerobic conditions, the accumulation of hydrogen ions is the limiting factor causing fatigue in runs of 300 to 800 meters.

The task now is to link this scientific information for design of accurate and working methods to developing training sessions for the lactate energy system. Distances of 300 to 600 meters may be used by coaches to do high lactate work. It is necessary to mentally and physically prepare to do this type of work due to the possibility of injury. High quality lactate work can shock the body and the central nervous system. Thus, loads (Total Distance and Volume) and intensities (Percent of Maximum) must be progressively sequenced. For example, sequencing workouts to prevent injuries may be achieved by planning each day of the week of an entire year. Each workout is a single unit of preparation designed to produce a desired result and each session is more demanding than the previous.

Recovery sessions from high quality lactate work must be sequenced in a set pattern. The duration of the exercise bout should be representative of the ration of recovery. If you have 60 seconds of exercise (400m), recovery should be 120 seconds if you wish to have a 1:2 ration. Other examples are 1:1.5, 1:1 depending on the goal of the training session. Prior knowledge of the athletes' work capacities and prior experience is essential in dictating the load and intensity in each unit. A first year athlete will not work at the same level that a fourth year athlete would. To fit into a "real live" training session, for example, the athletes on the same team would run the same distance and time on the interval (ie., 60 seconds for 400m). The novice athlete would rest (jog during rest) on every other repeat to fully recover from the high lactate work (a 1:4 ratio). The veterans would run at a 1:2 ration, since they are experienced and have developed the fitness to tolerate this high lactate work. Thus, allowing one coach to complete individual goals while training a large group. The intensity (ie. 60 seconds for 400m) is key to this type of training along with the recovery (a 1:4 or 1:2 ration).

The accumulation of lactate in working skeletal muscle will terminate this system after 50 to 60 seconds of maximum effort. Although all energy systems basically turn on at the same time, be aware that progressive recruitment of alternative pathways or systems occurs when one system is challenged more heavily, since another energy source has been depleted. Because of the very high quality work involved in the lactate system, in most cases, only 1 to 5 reps with full or near full recovery can be done twice a week. Only by challenging the right energy system will the desired physiological change and improved performance occur. Understand, at times, less work gives greater rewards.

The aerobic system is capable of utilizing proteins, fats and carbohydrates (Glycogen) for resynthesizing large amounts of ATP without simultaneously generating fatigue by-products with respect to sports. It is easy to see that the aerobic system is particularly suited for manufacturing ATP during prolonged endurance type activities. The intensity of the run dictates which energy system will be challenged and the method of ATP production in the muscle.

In the aerobic system, pyruvate from the glucose, glycogen and/or fatty acids (Stored Fats) are first converted to acetyl CoA, which is then oxidized to Carbon Dioxide (C02), and water (H20). Oxidation of acetyl CoA occurs in the Krebs Cycle (Citric Acid Cycle) and the electron transport system located in the mitochondrian of the muscle wall. For each molecule of blood glucose oxidized aerobically, 38 molecules of ATP are produced while muscle glycogen produces 39 molecules of ATP. Muscle glycogen is capable of producing 1 more molecule of ATP than blood glucose because it takes 1 ATP molecule to transfer blood glucose into the cell. The energy production in aerobic metabolism is 18 times greater than in the anaerobic system production of ATP.

Note that for this system to function, oxygen must be available, hence the term aerobic. It is the availability of oxygen in the cell which determines to what extent the process is aerobic and anaerobic. If the aerobic energy system cannot supply enough oxygen (anaerobic), pyruvate becomes a hydrogen acceptor and forms lactate. This is the critical step in the whole process when lactate forms, since it will eventually shut down all the energy systems. Note that lactate levels can become quite high using intensive tempo work since it borders on speed endurance and special endurance. Remembering that all energy systems turn on at basically the same time, intensive tempo running makes high demands on both the aerobic and anaerobic, and thus, is a sharing system.




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