Download Module 3- Bioenergetics - Bangen Athletic Development

Module 3: Bioenergetics
3.1 ATP and the Energy Pathways
Every process in the body (including muscle contraction) requires energy, and the
currency of energy in the body is adenosine triphosphate, or ATP. ATP has highenergy bonds located between the three phosphate groups. When these bonds are
broken, energy is released for the cells of the body to use.
The breaking of these bonds is known as hydrolyzation, and is an example of an
exergonic reaction, or a chemical reaction that releases energy. Typically chemical
reactions are catalyzed (or helped and sped up) by enzymes. The enzyme that aids
the hydrolyzation of ATP is ATPase (all enzymes end in “ase”). The end production
of this reaction is adenosine diphosphate, or ADP, and the separate phosphate
group.
The reverse of this chemical reaction, known as the phosphorylation of ADP can
occur as well. This is an endergonic reaction, as it requires energy to add the
phosphate group onto ADP to create ATP. The energy to perform this reaction
comes via the metabolic pathways, which converts the nutrients (carbohydrate,
protein and fat) of the food we eat into useable energy.
As there is a limited amount of ATP stored within the body, we must constantly
produce ATP to fuel the activities of the body. There are three main energy systems
that provides the body with energy: Phosphagen, Glycolytic and Oxidative. Within
these three energy systems there are four different metabolic pathways.
Of these metabolic pathways, two are anaerobic, meaning that they occur without
oxygen, and two are aerobic, which do require oxygen to occur. The two anaerobic
pathways are the phosphagen pathway (sometimes referred to as the ATP-PC or
creatine phosphate pathway) and anaerobic glycolysis (also called fast glycolysis).
The two aerobic pathways are aerobic glycolysis (slow glycolysis) and the oxidative
pathway.
Common Question:
What are the beginning substrates, location and rate-limiting step (availability of the
pathway’s enzyme) of each pathway?
PATHWAY
TYPE
LOCATION
SUBSTRATE
Rate Limiting
Step
ATP-PC
Anaerobic
Cytoplasm
Creatine
Creatine kinase
Phosphate
Glycolysis
Anaerobic
Cytoplasm
Glucose
Phosphofructokinase
Krebs cycle
Aerobic
Mitochondria
Acetyl CoA
Isocitrate
dehydrogenase
Electron
Aerobic
Mitochondria
Hydrogen
Cytochrome
transport
delivered by
oxidase
system
NAD and FAD
for oxidative
phosphorylation
The phosphagen pathway provides ATP primarily for short term, high intensity
activities. It is active at the start of any activity, regardless of intensity, because it
can provide quick energy. This pathway uses the breakdown of another high energy
phosphate molecule, creatine phosphate, to produce ATP. ADP and creatine
phosphate will combine, catalyzed by creatine kinase, to produce ATP and creatine.
This is a very high rate energy pathway, however, little creatine phosphate is stored
in the body.
At rest, the skeletal muscle concentration of creatine phosphate is four to six times
higher than ATP stores. Type II muscle fibers have a higher concentration of
creatine phosphate than type I fibers. The phosphagen system is controlled through
the law of mass action in which the concentrations of the reactants or products (or
both) in solution will drive the direction of the reaction.
Glycolysis is the breakdown of carbohydrate, either in the form of glycogen that has
been stored in the muscle, or glucose that is transported in the blood. Glycolysis
involves multiple enzymatically catalyzed reactions, thus the rate of producing ATP
is slower than the phosphagen pathway. However, the capacity is higher due to
larger stores of glucose.
The good news is that there is no need to memorize the above chart. However, there
are two important items to notice. First, the end result of this is pyruvate. Second, to
get to this point requires two ATP and produces two ATP. However, if glycogen is
used instead of blood glucose as the starting substrate, the step to convert glycogen
to glucose 6-phosphate does not require energy. Therefore the net energy
production will always be one ATP greater for glycogen (three ATP) versus glucose
(two ATP).
Glycolysis is stimulated by high concentrations of ADP, unbound phosphate groups,
and ammonia and by a slight decrease in pH levels and adenosine monophosphate
(AMP). Glycolysis is inhibited by very low pH levels, the presence of ATP, creatine
phosphate, citrate, and free fatty acids.
As mentioned earlier, there are two glycolysis pathways, anaerobic and aerobic.
During anaerobic glycolysis, pyruvate is converted to lactate, aided by the enzyme
lactate dehydrogenase. This produces ATP at a faster rate than aerobic glycolysis
but is limited in duration because the end products produces fatigue. It is important
to note that the end product is lactate and hydrogen ions, not lactic acid and it is
believed that it is these hydrogen ions that cause fatigue, not lactate.
Key Point:
The end result of lactate is that it is eventually transported in the blood to the liver,
where it is converted to glucose. This process is referred to as the Cori cycle.
During aerobic glycolysis, pyruvate is shuttled into the mitochondria of the muscle
cell and is converted into a substance known as acetyl-CoA. This acetyl-CoA is the
starting substance of the Krebs cycle, a metabolic process. This cycle produces
hydrogen-carrying molecules NADH and FADH2, which will be used to produce ATP
within the oxidative pathway.
The oxidative pathway is the primary source of ATP at rest and low intensity
exercise. It primarily uses carbohydrate and fat as substrates, but protein can be
used during starvation and very long bouts of exercise.
The oxidation of glucose and glycogen molecules begins with glycolysis and leads to
the Krebs cycle. The NADH and FADH2 molecules will transport hydrogen atoms to
the final oxidative metabolism process, the electron transport chain, where ATP is
produced from ADP.
If fat is used as the energy substrate in the oxidative pathway, either intramuscular
free fatty acids or free fatty acids are released from triglycerides through lipase and
circulate in the blood and eventually enter the muscle cells.
Triglycerides stored in fat cells can be broken down by hormone-sensitive lipase.
This releases free fatty acids from the fat cells into the blood, where they can
circulate and enter muscle fibers. The free fatty acids enter the mitochondria, are
broken down, and form acetyl-CoA and hydrogen protons. The acetyl-CoA enters the
Krebs cycle and NADH and FADH2 carry the hydrogen atoms to the electron
transport chain. Significantly more ATP is produced with fat than carbohydrate,
however, there are many more chemical reactions decreasing the rate of production.
Protein is not a significant source of energy for most activities, but if needed it is
broken down into amino acids, and the amino acids are converted into glucose,
pyruvate, or various Krebs cycle inter-mediates to produce ATP.
3.2 Fueling Physical Activity and Fatigue
Key Point:
All four energy system pathways are providing at least some ATP at all times
The extent to which each of the three energy systems contributes to ATP production
depends primarily on the intensity of muscular activity and secondarily on the
duration. At no time, during either exercise or rest, does any single energy system
provide the complete supply of energy.
The phosphagen energy system primarily supplies ATP for high-intensity activities
of short duration, the glycolytic system for moderate- to high-intensity activities of
short to medium duration, and the oxidative system for low-intensity activities of
long duration.
Common Question:
What is the ranking in terms of rate and capacity of the four energy pathways?
ATP Production Rate
1. Phosphagen
2. Anaerobic Glycolysis
3. Aerobic Glycolysis
4. Oxidation of Carbohydrates
5. Oxidation of Fats and Proteins
ATP Production Capacity
1. Oxidation of Fats and Proteins
2. Oxidation of Carbodydrates
3. Aerobic Glycolysis
4. Anaerobic Glycolysis
5. Phosphagen
Oxygen uptake (also known as oxygen consumption) is a measure of a person’s
ability to take in and use oxygen to fuel activity. Maximum oxygen consumption, or
VO2 Max is an individual’s maximum ability to take in and utilize oxygen to fuel
activity. During physical activity there are four markers related to oxygen
consumption that give insight to energy pathway usage: lactate threshold, onset of
blood lactate accumulation, oxygen deficit and excess post-exercise oxygen
consumption.
Lactate threshold represents an increased reliance on anaerobic metabolism and
the use of intermediately sized motor units. Lactate threshold occurs because of an
increased rate of glycolysis, decreased lactate removal rate or capacity and
insufficient oxygen availability. Lactate threshold is often used as a marker of the
anaerobic threshold. Occurs at 50-60% of VO2 max for untrained individuals and
70-80% for trained individuals (training will improve lactate threshold).
The Onset of Blood Lactate Accumulation (or OBLA) occurs when the concentration
of blood lactate reaches 4 mmol/L. At rest this concentration is less than 1 mmol/L.
OBLA occurs at a higher exercise intensity than lactate threshold and represents an
even greater reliance on anaerobic metabolism and the use of the largest motor
units.
Endurance training at intensities near or above the lactate threshold or onset of
blood lactate threshold pushes these markers to occur at higher exercise intensities.
This shift probably occurs as a result of changes in hormone release and increased
mitochondrial content. This shift allows athletes to perform more work before
fatigue sets in.
Oxygen deficit is the anaerobic contribution to the total energy cost during the start
of exercise. This phenomenon occurs because of the time it takes for the aerobic
energy systems to “kick in” to supply sufficient amounts of energy (remember to
relative rates of ATP production).
Due to this lack of oxygen early in exercise, anaerobic pathways are needed to
produce ATP. Pyruvate and NADH will be converted to lactate and hydrogen
because there was not enough oxygen in the mitochondria. As mentioned earlier, it
is the hydrogen ions, not lactate that can cause fatigue. This is because of the
following mechanisms occur due to increase hydrogen concentration:
 Interferes with calcium binding to troponin
 Reduces calcium release from sarcoplasmic reticulum
 Decreases the ph, causing phosphofructokinase to slow down glycolysis
 Chemical receptors in the cell detect hydrogen (burning sensation), affects
the CNS and can eventually causes inhibition of motor unit recruitment by
the motor cortex
Excess post-exercise oxygen consumption, also known as EPOC or oxygen debt,
occurs when the oxygen uptake value (VO2) is still elevated once exercise is ended
in order to restore the body to return to its pre-exercise state.
Common Question:
What are the possible mechanisms that increase excess post-exercise oxygen
consumption?
 Resynthesis of ATP and creatine phosphate stores
 Resynthesis of glycogen from lactate
 Oxygen resaturation of tissue water, venous blood, skeletal muscle blood and
myoglobin
 Redistribution of ions within various body compartments
 Repair of damaged tissue
 Additional cardiorespiratory work
 Residual effects of hormone release and hormone accumulation
 Increased body temperature
Key Point:
Higher intensity activity will increase both the oxygen debt and deficit (EPOC).
Longer duration activity will increase excess post-exercise oxygen consumption
only.
A major factor in fatigue of physical activity is the depletion of two of the major
substrates that fuel physical activity: creatine phosphate and glycogen. Creatine
phosphate can decrease markedly (50-70%) during the first stage (five to thirty
seconds) of high-intensity exercise and can be almost eliminated as a result of very
intense exercise to exhaustion (one to two minutes). Post-exercise phosphagen
repletion/recovery can occur in a relatively short period. Complete resynthesis of
ATP appears to occur within 3 to 5 minutes, and complete creatine phosphate
resynthesis can occur within 8 minutes.
Must Know:
The half-life of creatine phosphate replenshment is 30 seconds. Therefore creatine
phosphate stores will be 50% recovered in 30 seconds, 75% in 60 seconds, 87.5% in
90 seconds, etc.
The rate of glycogen depletion is related to exercise intensity. At relative intensities
of exercise above 60% of maximal oxygen uptake, muscle glycogen becomes an
increasingly important energy substrate; the entire glycogen content of some
muscle cells can become depleted during exercise. Repletion of muscle glycogen
during recovery is directly related to post-exercise carbohydrate ingestion.
Must Know:
Repletion appears to be optimal if 0.7 to 3.0 g of carbohydrate per kg of body weight
is ingested every two hours following exercise.
Common Question:
What are the bioenergetic limiting factors of various exercise intensities and
durations?
 Low and moderate intensity, short duration: no bioenergetic limiting factors





Low intensity, long duration (marathon run): muscle and liver glycogen
stores are major factors, fat stores are a moderate factor.
Moderate intensity, moderate duration (1,500 meter run): no major
bioenergetic factors, muscle glycogen stores and increased hydrogen
concentration (lowered pH) are moderate factors.
High intensity, moderate duration (400 meter run): increased hydrogen
concentration is a major factor, ATP, creatine phosphate and muscle glycogen
stores are moderate factors.
Very high intensity, short duration (discus throw): no major bioenergetics
factors, ATP and creatine phosphate stores are moderate factors.
Repeated very high intensity, short duration (repeated 20 meter sprints):
Increased hydrogen concentration and ATP, creatine phosphate and muscle
glycogen stores are all major factors.
3.3 Nutrients and Diet
There are three macronutrients: carbohydrate, protein and fat. Macronutrients are
nutrients that are required in significant amounts in the diet.
Carbohydrates are the primary energy source in the body. It provides four calories
per gram. They can exist as monosaccharides (one molecule sugars), disaccharides
(two one molecule sugars joined together) and polysaccharides (complex
carbohydrates). During digestion all carbohydrates are converted to glucose and
stored as glycogen. The conversion of glucose to glycogen is glycogenesis (the
reverse is called glycogenolysis).
Carbohydrate can be classified as simple or complex. Simple carbohydrates are
digested and absorbed quickly and complex carbohydrates are digested and
absorbed more slowly. The glycemic index classifies carbohydrates as simple or
complex, those with higher numbers are simpler.
Fiber content is another important aspect of carbohydrate. Fiber aids in digestion,
increases motility in the intestines and increases feelings of fullness.
Must Know:
Daily recommendations for carbohydrates:
 50 to 100 grams is needed to prevent ketosis (use of protein for energy)



General Population: 45-65% of total calories
Aerobic endurance athletes (>90 min/day): 8-10g/kg
Resistance/Power Athletes: 5-6g/kg
Fiber daily requirements:
 Men: 38 g/day

Women: 25 g/day
Protein is the building blocks of all tissues and hormones. Like carbohydrate,
protein provides four calories of energy per gram. Protein exists as chains of amino
acids. There are nine essential amino acids (histidine, isoleucine, leucine, lysine,
methionine, phenylalanine, threonine, tryptophan, and valine) and eleven nonessential amino acids (alanine, arginine, asparagine, aspartic acid, cysteine, glutamic
acid, glycine, glutamine, proline, serine and tyrosine). Essential amino acids are
those that must be consumed (they cannot be converted from other amino acids by
the body) and the non-essential amino acids do not have to be consumed (they can
be converted from other amino acids).
Common Question:
Which foods are complete or high quality proteins?
 Complete or high quality protein foods are those that contain all of the
essential amino acids.
 Animal product foods (such as fish, poultry, meat, eggs and dairy products)
are complete/high quality proteins.
Must Know:
Daily recommendations for protein:
 General: 10-15% of total calories
 General Population: 0.8g/kg
 Aerobic Endurance Athlete: 0.8-1.4 g/kg
 Resistance/Power Athlete: 1.7g/kg
 Athletes (in general): 1.5 to 2g/kg
Fats function as membranes, hormones and hormone transport and energy stores.
Fat provides nine calories of energy per gram. The bonds within each fat molecule
will dictate the type. Fats with no double bonds are saturated fats, those with one
double bond are monounsaturated fats, and those with two or more double bonds
are polyunsaturated.
Not all fat is bad. High-density lipoproteins (HDL) help prevent cardiovascular
disease and are found in fish oil, flaxseed oil, fruits and vegetables, whole grains and
beans. Docosahexaenoic acid (DHA) is important for nervous system growth and
restoration, helps prevent cardiovascular disease, aids fetal growth during
pregnancy and is abundant in fish and their oils, game, seeds and plants.
Must Know:
Daily recommendations for fats:
 General Population: 20-35% of total calories
 Athletes: 15-35% of total calories
 Less than 10% of calories from saturated fat
 Avoid trans-fatty acids or “partially hydrogenated” fats
Common Question:
Macronutrient Calculations:
To determine amount of calories of macronutrient: multiply percentage by total
number of calories
For example: 55% of 2000 calories is carbohydrate = 2000 x 0.55 = 1100
carbohydrate calories.
To determine total number of calories from a macronutrient percentage: divide
macronutrient calories by percentage
For example 500 calories of protein is 20% = 500/0.2 = 2,500 total calories
To determine amount of macronutrient from number of calories: divide
macronutrient calories by amount per calories
For example 500 calories of protein (4 calories per gram) = 500/4 = 125 grams of
protein.
To determine caloric amount of macronutrient from number of grams: multiply
macronutrient weight by amount per calorie of macronutrient
For example 200 grams of protein = 200 x 4 = 800 calories of protein
Micronutrients are nutrients that are required in small amounts (typically measured
in milligrams, or even smaller quantities) in the diet. There are two types of
micronutrients: vitamins and minerals. They both serve specific functions for the
metabolism of the body (see tables 10.5 and 10.6 in the text).
Vitamins are either water soluble (vitamins B and C) or fat soluble (vitamins A, D, E
and K).
In general the recommendations for vitamins and minerals are the same as the
general population. Exceptions may be for Vitamin C and D, iron, calcium and
electrolytes (sodium chloride and potassium). Vitamins and mineral do have upper
limits, which if consumed, may be toxic.
Water is the largest component of the body, representing from 45% to 70% of a
person’s body weight. Total body water is determined largely by body composition;
muscle tissue is approximately 75% water, whereas fat tissue is about 20% water
Must Know:
Daily hydration recommendations:
 Average Male: 3.7 L per day; Average Female: 2.7 L per day
 Athletes need 3-4 gallons (11-15 L) more than general population
Fluid loss equal to as little as 1% of total body weight can be associated with an
elevation in core temperature during exercise. Fluid loss of 3% to 5% of body
weight results in cardiovascular strain and impaired ability to dissipate heat. At 7%
loss, collapse is likely and death is possible.
Signs of dehydration include the following:
 Dark yellow, strong-smelling urine
 Decreased frequency of urination
 Rapid resting heart rate
 Prolonged muscle soreness
Must Know:
Nutrition surrounding training or competition:
Before:
 Meal 2-4 hours before should be high in carbohydrate, moderate in protein,
low in fat, should be familiar and known to digest well
 Snack 30 minutes prior with 15-25 grams of carbohydrate, 4-8 grams of
protein
 Hydration of 1 pint (or 0.5 liters) prior to competition
During:
 Small amounts of carbohydrate (4-6 grams) and protein (1-2 grams) every
fifteen to thirty minutes of activity
 Hydrate with eight ounce doses as needed (approximately every 15 minutes)
After:
 Immediately after- with 6-8 grams of simple sugar, 16-18 grams of protein,
and approximately 75 grams of total carbohydrate
 One to two hours after- a full meal (composition depends on
competition/training schedule)
 Hydration must replace every pound lost with 1 pint (0.5 Liters) of fluid
3.4 Ergogenic Aids
Ergogenic aids are any substance, mechanical aid, or training method that improves
sport performance. For the purposes of this certification, the term refers specifically
to pharmacological aids.
Anabolic steroids are the synthetic (man-made) derivatives of the male sex
hormone, testosterone. Ingestion results in increases in muscle protein synthesis
with steroid which are responsible for increases in lean body mass. Increased
strength and fat loss are also benefits of this ergogenic aid.
Anabolic steroid use is associated with changes in aggression, arousal, and
irritability. Increased cholesterol, elevated blood pressure, sex organ dysfunction,
acne and hormonal disruption are also possible negative effects of steroid use. In
addition, this is an illegal and banned substance.
Athletes typically use anabolic steroids in a “stacking” regimen, in which they
administer several different drugs simultaneously. The potency of one anabolic
agent may be enhanced when it is consumed simultaneously with another anabolic
agent. Most users take anabolic steroids in a cyclic pattern, meaning that they use
the drugs for several weeks or months and alternate these cycles with periods of
discontinued use. Often athletes administer the drugs in a pyramid (step-up)
pattern in which dosages are steadily increased over several weeks. Toward the end
of the cycle, the athlete “steps down” to reduce the likelihood of negative side
effects.
Growth hormone is used to increase muscle mass and decrease body fat. Overuse
may lead to excess secretion by the pituitary gland leading to cardiovascular, kidney
problems and gigantism. Growth hormone is a banned substance.
Testosterone Precursors (Prohormones) are designed to result in the same
improvements as anabolic hormones. They also result in the same adverse effects.
These are banned substances.
Human Chorionic Gonadotropin, when injected into men, can increase testicular
testosterone production. This is a banned substance.
Insulin can be used to increase protein synthesis, but the side effect of hypoglycemia
can be fatal. Performance enhancement use is banned, but this is very difficult to
detect.
Erythropoietin (EPO) injection leads to elevations in both hematocrit (concentration
of red blood cells in the blood) and hemoglobin (oxygen carrying protein in the
blood). Health risks include increased risk of blood clotting, elevations in systolic
blood pressure, a compromised thermoregulatory system, and dehydration during
aerobic endurance events. It is a banned substance.
Beta-Adrenergic Agonists can increase lean mass and decrease stored fat. Use of this
substance is prohibited.
Beta-Blockers reduce anxiety and tremors during performance and is, therefore,
useful for target sports like shooting or archery. Banned.
Beta-Hydroxy-Beta-Methylbutyrate (HMB) is another banned substance that has
both anabolic and lipolytic effects.
Essential amino acids or other protein supplements can augment muscle protein
synthesis in healthy human subjects. These are legal substances.
Beta-Alanine, Sodium Bicarbonate and Sodium Citrate are nutritional muscle buffers
that can delay anaerobic fatigue and improve recovery during intermittent high
intensity exercise. These are not banned.
L-Carnitine is a legal substance used to increase lipid oxidation and may enhance
recovery from exercise.
Creatine supplementation has been shown to increase strength and improve
training by reducing fatigue and enhancing recovery within and after high intensity
activity like resistance training. Prolonged creatine supplementation has been
generally associated with increases in body weight, especially increases in fat-free
mass. Though there is some water weight gain as a result of use.
Creatine supplementation can increases the creatine content of muscles by
approximately 20%, but there is a saturation limit. Doses are typically 5 grams per
day. An introductory period of 20 grams per day for five days may or may not be
used.
Controlled studies have been unable to document any significant side effects from
creatine supplementation, though concerns include gastrointestinal disturbances
and strain on the kidneys. Creatine is a legal supplement.
Caffeine has been show to increase time to exhaustion, especially during aerobic
activities. It has many adverse effects, including anxiety, gastrointestinal
disturbances, restlessness, insomnia, tremors, heart arrhythmias, increased risk for
heat illness and can be physically addicting. Small amounts of caffeine are not
banned, but there are limits during competition.
Ephedrine also been shown to improve aerobic endurance performance, but is only
effective when taken in combination with caffeine. Ephedrine has many similar
adverse effects as caffeine, but much more severe and may lead to death. Unlike
caffeine it is banned by most sport governing bodies and illegal.
3.5 Weight Management
For athletes, there are typically two goals of weight management: fat loss and lean
mass gain. The body can exist in three possible states:
 Caloric balance occurs when the caloric intake is equal to the energy
expenditure. This will maintain body weight.
 Negative caloric balance occurs when caloric intake is less than energy
expenditure. This will cause a loss of body weight.
 Positive caloric balance occurs when caloric intake is greater than energy
expenditure. This leads to an increase in body weight.
Daily energy expenditure is based on three factors:
1. Resting Metabolic Rate- this is the amount of energy expended for
cardiorespiratory function and thermoregulation during daily activity. Makes
up approximately 60-75% of total calories.
2. Physical Activity- the calories expended during exercise and daily activity.
Will vary greatly among individuals.
3. Thermic Effect of Food- the energy expended to digest and store food. Is
responsible for approximately 7-10% of total expenditure.
Must Know:
Estimated Daily Calorie Needs of Males and Females by Activity Level
Males
Females
Activity level
Calories per lb Calories per kg Calories per lb Calories per kg
Light
17
38
16
35
Moderate
19
41
17
37
Heavy
23
50
20
44
To gain lean muscle mass add 350 to 700 calories per day to gain at a rate of 1 to 2
pounds per week. Must combine diet with resistance training to gain muscle mass.
Need to eat a balanced diet with added protein (1.5 to 2 grams of protein per
kilogram of body mass, more so for vegetarian athletes). Adding weight without
resistance training will lead to increases in body fat instead of lean tissue.
Must Know:
Need a positive caloric balance of approximately 2500 calories in order to gain one
pound of muscle mass.
Want to lose weight gradually (no more than 1% of bodyweight per week) by
decreasing caloric intake by 500 to 1000 per day. Never reduce diet below 1800 or
2000 kcal per day. Should eat balanced diet with nutrient dense, not energy dense
foods. Fat loss should be attempted during the off or pre-season to prevent
performance decrements. During caloric restriction there is an increased risk of
dehydration, vitamin and mineral deficiency and loss of lean tissue.
Must Know:
Need a negative caloric balance of approximately 3500 calories in order to lose one
pound of fat.
Two most common eating disorders are anorexia nervosa and bulimia. Some may
have both. It is never the responsibility of anyone other than a professional to
diagnose or treat these. However, understanding the warning signs to protect
athletes and refer them to an expert is important.
Warning signs for anorexia nervosa:
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Commenting repeatedly about being or feeling fat and asking questions
about weight even if weight is below average.
Dramatic weight loss for no medical reason.
Reaching a weight that is below the ideal competitive weight for that athlete
and continuing to lose weight even during the off-season.
Pre-occupation with food, calories and weight.
Warning signs for bulimia:
 Eating secretively, which may be noted by finding food wrappers or
observing someone sneaking food.
 Disappearing repeatedly immediately after eating, especially if a large
amount of food was eaten.
 Appearing nervous or agitated if something prevents the person from being
alone shortly after eating.
 Losing or gaining extreme amounts of weight.
 Smell or remnants of vomit in the rest room or elsewhere.
 Disappearance of large amounts of food.
Warning signs for both disorders:
 Complaining frequently of constipation or stomachaches
 Mood swings
 Social withdrawal
 Relentless, excessive exercise
 Excessive concern about weight
 Strict diets followed by binges
 Increasing criticism of one’s body
 Strong denial that a problem exists even when there is hard evidence
Module 3 Practice Questions
1. Which of the following is the best example of a complete protein?
A. Almonds
B. Eggs
C. Soy Milk
D. Butternut Squash
2. Which of the following types of chemical reactions best describes the
hydrolyzation of ATP to ADP, P and Energy?
I. endergonic
II. exergonic
III. anabolic
IV. catabolic
A. I and III only
B. I and IV only
C. II and III only
D. II and IV only
3. Which of the following energy systems are in use during the first six seconds of
any activity?
A. phosphagen
B. aerobic
C. anaerobic glycolysis
D. all of the above
4. What is the appropriate protein intake for a 120 lb female cross-country skier?
A. 120 grams
B. 240 grams
C. 204 grams
D. 72 grams
5. The lactate threshold intakes an increased reliance on which of the following
energy pathways?
A. aerobic glycolysis
B. ATP-PC
C. anaerobic glycolysis
D. oxidation of fats
6. What is the rate limiting step for the ATP-PC (phosphagen) system?
A. PFK
B. isocitrate dehydrogenase
C. creatine kinase
D. ATPase
7. Which of the following two minerals are very important to the female athlete?
I. Iron
II. Magnesium
III. Selenium
IV. Calcium
A. I and II only
B. I and IV only
C. II and IV only
D. III and IV only
8. Which of the following is NOT an ergogenic benefit of testosterone?
A. increased muscle mass
B. increased concentration on workouts
C. increased strength
D. increased performance with training
9. Which of the following has the greater net of ATP during glycolysis?
A. glycogen
B. glucose
C. they have the same net of ATP
D. more information is needed to answer this question
10. A 200 lb male athlete with a high level of physical activity would like to gain 4
pounds of muscle mass over the next 8 weeks. What does his new caloric intake
need to be to help him reach this goal?
A. 4600 kcal/day
B. 5850 kcal/day
C. 4780 kcal/day
D. 4960 kcal/day
11. Which of the following ergogenic aids does NOT result in increased protein
synthesis?
A. testosterone
B. creatine
C. growth hormone
D. branched chain amino acids
12. If Simon, who normally has a caloric intake of 5500 calories, decreases his
caloric intake to 5375, how long will it take him to lose 4 pounds?
A. 4 weeks
B. 8 weeks
C. 12 weeks
D. 16 weeks
13. Which of the following energy system pathways can produce ATP at the highest
rate?
A. Oxidation of fats and proteins
B. Krebs Cycle
C. Oxidation of carbohydrate
D. Anaerobic Glyolysis
14. Which of the following carbohydrate recommendations is most appropriate
immediately after exercise?
A. 16-18 grams of simple carbohydrate
B. 6-8 grams of complex carbohydrate
C. 6-8 grams of simple carbohydrate
D. 16-18 grams of complex carbohydrate
15. Where in the body is lactate converted back to glucose?
A. liver
B. kidney
C. pancreas
D. blood
16. How does creatine improve muscle mass and strength
A. Increases protein synthesis
B. Allows more energy for long duration activities and aids in recovery
C. Allows more energy for intense, short term activities and aids in recovery
D. Allows more energy for intense, short term activities and decreases recovery
17. Which of the following muscle fiber types has a higher store of creatine
phosphate?
A. type I
B. type II
C. they have the same amount
D. depends on the individual
18. An eighteen year old, 120 lb female collegiate cross-country has the following
average energy intake:
500 grams of carbohydrate
25 grams of protein
50 grams of fat
What nutritional information would you recommend?
A. Increase her fat content
B. Increase her carbohydrate content
C. Increase her protein content
D. Decrease her carbohydrate content
19. Which of the following workouts would have the highest amount of oxygen
deficit and oxygen debt?
A. 20 minutes at 40% VO2 Max
B. 20 minutes at 60% VO2 Max
C. 20 minutes at 80% VO2 Max
D. 20 minutes of 30 second on, 1 minute off intervals at 95% Maximum Power
Output
20. Which of the following ergogenic aids must be used in conjunction with caffeine
in order to be effective
A. Ephedrine
B. Creatine
C. Beta Blockers
D. Insulin
Module 3 Practice Question Answers
1. B (Module 3.3)
2. D (Module 3.1)
3. D (Module 3.2)
4. A (Module 3.3)
5. C (Module 3.2)
6. C (Module 3.1)
7. B (Module 3.3)
8. B (Module 3.4)
9. A (Module 3.1)
10. C (Module 3.5)
11. B (Module 3.4)
12. D (Module 3.5)
13. D (Module 3.2)
14. C (Module 3.3)
15. A (Module 3.1)
16. C (Module 3.4)
17. B (Module 3.1)
18. C (Module 3.3)
19. D (Module 3.2)
20. C (Module 3.4)