ENERGY SYSTEMS Flashcards
FORCE-FATIGABILITY CURVE
3
(1) Demonstrates the inherent tradeoff between the production of maximum force & power and the ability to sustain it.
(2) Sports that produce maximum levels of force have extremely low durations (shot put, powerlifting)
(3) At the other end of the spectrum are sports that take place over longer duration with a relatively low level of force (i.e.. long-distance running)
What are the primary causes of the tradeoff between the level of force and the ability to sustain it?
Boils down to how your body produces energy
What are the two different ways the body can produce energy?
(1) Aerobically (with oxygen)
2) Anaerobically (without oxygen
How are the energy pathways fueled? (2)
(1) By the macronutrients that come from your food.
(2) Every cell in your body requires energy, and in response to exercise, the energy demand increases.
THE ENERGY CYCLE
(1) The body takes the foods you eat (i.e. proteins, carbs, fats) and turns them into fuel that cells, tissues, and muscles, can use.
(2) Each of these nutrients is then either (a) utilized in the bloodstream, or (b) stored to be mobilized and used as needed.
3 MAIN ENERGY SYSTEMS
(1) Phosphocreatine System
(2) Anaerobic Glycolysis System
(3) Aerobic System
The power output generated by the 3 main systems differs dramatically
(1) Phosphocreatine - highest power output, short duration (10-15 secs)
(2) Anaerobic Glycolysis - high power output, moderate duration (30-90 secs)
(3) Aerobic System - lowest power output, long duration (majority of energy production for exercise lasting more than 60 secs)
THE RELATIONSHIP BETWEEN THE AEROBIC & TWO OTHER ANAEROBIC SYSTEMS
(2)
(1) Govern the amount of power your body can generate
(2) Which one of these systems you choose to develop or emphasize will depend on your goals and the demands of your sport.
AEROBIC FITNESS (3)
(1) Provides the majority of energy production for any activity lasting longer than 60 seconds, regardless of the intensity level
(2) Drives the restoration of homeostasis within the cellular environment following anaerobic energy production
(3) Produces the ATP necessary to support life 24/7 throughout your entire life
3 MAIN STAGES OF AEROBIC ENERGY PRODUCTION
(1) Glycolysis
(2) The Krebs Cycle
(3) The electron transport & chemiosmosis
WHY DOES EVERYONE NEED AEROBIC FITNESS?
2
(1) A number of important prospective studies have shown VO2 Max is the most important predictor of all-cause mortality
(2) Risk of cardiovascular disease decreases linearly with increases in aerobic fitness
Even though the aerobic process is longer than those involved in the other two systems, why is it more efficient?
It produces more molecules of ATP per molecule of substrate, making it more efficient.
Why is the aerobic system the most “metabolically adaptable”?
It can produce ATP from multiple energy sources
- carbs
- fats
- proteins
Why is the aerobic system the most adaptable system when it comes to room for improvement?
Since there are so many components to the system, there are many ways in which each of these components can be promoted such that overall aerobic fitness increases.
3 KEYS TO IMPROVING AEROBIC FITNESS
(1) Increase Functional capacity of the heart itself
(2) Build a bigger vascular network
(3) Increase the number of mitochondria
Increase Functional capacity of the heart itself
To deliver more oxygen to working muscles and supporting tissues (i.e. hypertrophy, contractile, elasticity)
Build a bigger vascular network (2)
(1) To be able to deliver more blood & oxygen throughout the body.
(2) This means more blood vessels and capillaries.
Increase the number of mitochondria
As well as their ability to function, in order to improve how well tissues can utilize oxygen that gets delivered to them
Training the aerobic system involves stimulating what 2 kinds of adaptations? (2)
(1) Cardiovascular & skeletal muscle
(2) Promoting either of these 2 components leads to increased blood flow and oxygen delivery extraction
Training for aerobic adaptations requires what three things regarding aerobic programming?
(1) A variety of volumes & intensities
(2) A high training frequency
(3) Sport-specific movements
A variety of volumes & intensities
To maximally develop aerobic fitness, a variety of volumes and intensities must be used - not just high intensity
A high training frequency (2)
(1) 4 - 6 days a week because there is a high turnover of mitochondria
(2) 2 - 3 days per week of training is not enough for long-term aerobic development
Sport-specific movements
More important for developing oxygen utilization (i.e. muscles, than for improving oxygen supply)
Explain lactate as a fuel source
Is an important fuel source for many tissues, including the heart itself
Lactic System
2
(1) Provides energy for any activity lasting up to about 30 seconds
(2) Primary role is to allow higher levels of force and power to be generated over longer periods of time than what the Phosphocreatine system can do
Two ways that glucose can be broken down into ATP
(1) Aerobic glycolysis (with oxygen)
2) anaerobic glycolysis (without oxygen
Explain lactate production (2)
(1) Is always produced as a by-product of carb metabolism (both aerobically & anaerobically)
(2) It only accumulates when the aerobic system can’t keep up with the rate at which it’s being produced
Why do we get tired? (5)
(1) NOT caused by lactic acid
(2) Includes both central & peripheral factors
(3) Is protective to maintain homeostasis
(4) Is multifactorial depending on activity
(5) Muscles never run out of ATP
Lactate can be transported to:
3
(1) Other cells nearby where it is produced
(2) To the heart, brain, etc. (primary fuel source for the heart)
(3) Working muscles in other areas of the body
WHAT ARE SOME FACTORS OF FATIGUE? (7)
(1) Increase in Phosphate
(2) Changes in Calcium
(3) Muscle Temp
(4) Change in PH
(5) Substrates
(6) Reactive Oxidative Species (ROS) production
(7) Central factors
What are 2 guidelines for training the lactic system?
(1) Power training that lasts no more than 30 - 40 secs with long resting periods (2-4 min) - More rest is not better
(2) Lactic training methods lasting more than 45 sec are more about improving the ability to maintain the cellular environment while increasing high intensity aerobic fitness.
Continued anaerobic metabolism
Leads to high levels of fatigue because it leads to large changes within the cellular environment that impair energy production and contractility
THE ANAEROBIC-ALACTIC SYSTEM
3
(1) Most powerful, yet least adaptable of all energy systems
(2) Also known at ATP-PC
(3) Able to regenerate ATP the fastest because there are the fewest chemical steps and it uses the most powerful substrates - phosphates.
WHY IS THE ALACTIC SYSTEM LIMITED?
Mostly limited By the storage of ATP and phosphocreatine as well as enzymes and can only produce high amounts of energy for a few seconds
WHAT IS THE ALACTIC SYSTEM SRIVEN BY?
Biologically, driven by the sympathetic nervous system to produce maximum force and power output for a very short period of time to support the “fight or flight” response necessary for survival
COMPARE THE ALACTIC SYSTEM TO THE LACTIC AND AEROBIC SYSTEMS.
It is incredibly simplistic, which is why it is able to produce ATP so quickly, but it’s not very adaptable.
How do you improve ALACTIC fitness? (3)
(1) Alactic system primarily drives the largest, highest threshold fibers that produce the most force.
(2) Increases are mostly the result of increasing size/contractile abilities of these fibers
(3) Marginal increases (and even aerobic fitness) can be seen by increasing storage of phosphocreatine (I.e. via creatine supplementation)
What are two guidelines for training alactic fitness?
(1) Training methods must be short work periods of 3-6 seconds, with rest periods of 1-3 minutes or more
(2) Improving aerobic fitness as higher levels of aerobic fitness will speed up the ability of the alactic system to contribute energy again in repeated bouts (within limits)
What is a key aspect to consider regarding the use of the ALACTIC system?
The use of this system leads to the fastest rate of fatigue, so it must be used wisely.
Discuss what contributes and hinders greatly to a good alactic system.
It is the most genetic and least adaptable system.
Where is the alactic system utilized the most?
Used the most in very high power output sports and in conjunction with the aerobic system in repetitive sprint activities- many sports use this combination
ENERGY SYSTEMS & PERFORMANCE (2)
(1) Each sport or activity challenges energy production in different ways based on power output (sympathetically driven) and work to rest ratios.
(2) Every adaptive response in the body is about meeting the demands of the environment while maintaining homeostasis so energy can be maintained.
Each sport/environment can be broken down into 3 different components in terms of energy requirements. (4)
(1) Rate of energy production
(2) Duration of energy production
(3) Work to rest ratio
(4) These variables define the unique environment the body faces as it must generate power to meet the needs of the sport.
RATE OF ENERGY PRODUCTION
Defined by how rapidly ATP is generated during the work period (high rate = high power)
Duration of energy production
Defined by how long increased energy must be produced
WORK TO REST RATIO
Variation between lengths of work periods and rest
What are energy systems driven by? (2)
(1) The specific demands for power output over time.
(2) Higher levels of power output require more energy to be produced to sustain the movement.
What occurs when the greater percent of total energy produced comes from the aerobic system?
The longer it can be maintained over time.
WHY IS TRYING TO DETERMINE EXACT PERCENTAGE OF ENERGY SYSTEM CONTRIBUTION ACROSS DIFFERENT SPORTS GENERALLY A WASTE OF TIME & MISLEADING?
There is not exact way to quantify energy system percentage and everyone will be different depending on their movement and their brain’s perception of the environment.
SIMPLE RULES OF THUMB FOR ENERGY SYSTEMS CONTRIBUTION (3)
(1) If work period is less than 1 minute, it’s largely anaerobic
(2) If work period is greater than 1 minute, it’s largely aerobic
(3) If worm period is intermittent, then it’s aerobic-alactic
During all-out maximum effort, what occurs at 20 - 30 seconds?
A crossover to aerobic dominance
What occurs with repeated activities the more they are repeated?
They become more & more aerobic as they are repeated
What is important to note in how the energy systems work?
They work together, not in isolation
DYNAMIC ENERGY CONTROL
Is the concept of managing energy expenditure so that you are only tapping into the highest force and power output as needed so that you can maintain the maximum level of performance as long as possible
What has a huge influence on energy production?
2
(1) The stress response
(2) By limiting the stress response, we can limit energy expenditure to maintain performance. 
What are the four factors influencing the stress response?
(1) Familiarity with environment
(2) Stress tolerance skills
(3) Fitness level
(4) Energy management
Familiarity with environment
Being familiar with the specific environment reduces stress because the brain knows what to expect (i.e. Location, temperature, noise, surface, elevation, etc.)
Stress tolerance skills
The ability to perform under pressure is a skill that needs to be trained and developed.
Fitness level
2
(1) Higher aerobic fitness and greater parasympathetic nervous system function (HRV) Helps effectively regulate the stress response.
(2) Movement capacity and effective breathing patterns drive increased airflow and reduced energy expenditure. 
Energy management (2)
(1) One of the most important conditioning skills is learning how to effectively manage energy by consciously controlling pace and power output.
(2) This skill needs to be developed through heart rate training focussing on building awareness and control of energy expenditure (HR) And recovery.
What is a skill set and hugely important element of conditioning?
Dynamic energy control and managing the stress response
Each of the four components of stress response management must be…
Developed and trained as a central part of programming throughout the year
