Flashcards in Final Review Deck (75):
Provide an example of what is meant by studying acute responses to a single bout of
- what immediately happens when you begin your work out
- ex. increased cardiac output
- ex. decreased blood flow to visceral organs
Describe what is meant by studying chronic adaptations to exercise training.
- long term effects
- ex. muscular walls in the heart enlarge
- ex. increased respiratory capacity
- ex. improved body composition
What factors must you consider when designing a research study to ensure that you get accurate and reproducible results?
- easily reproducible data collection technique
- specific procedure
- clear population
- budget friendly
- manpower availability
Define the term ergometer
- an apparatus that measures work or energy expended during a period of physical exercise .
Explain the function of an ergometer.
.- evaluate the fitness level of the athlete
- measuring work done by exercising
Advantages of using cycle ergometers for exercise testing in clinical and research settings:
- less expensive
- minimal upper body movement (easier to measure HR and BP)
- more applicable for measuring cycling performance
- occupies less space
Disadvantages of using cycle ergometers for exercise testing in clinical and research settings:
- people may not be accustomed to cycling (premature fatigue, fail to reach true max cardio output, 10-15% underestimation of VO2 max)
- BP slightly higher than treadmill tests (due to longer muscle contractions)
- Accuracy is based on prediction of MHR
- equipment must be well maintained/calibrated
Advantages of using treadmills for exercise testing in clinical and research settings:
- higher cardiovascular responses
- exercise is controlled by observer (speed), yields more reproducible data
- breathing is easier
Disadvantages of using treadmills for exercise testing in clinical and research settings:
- need space
- need money for treadmill
- upper body movement
- may not be an option if you are obese or have musculoskeletal issues or injuries
- needs maintenance
- can be loud
Explain the placebo effect.
- a beneficial effect
- produced by a placebo drug or treatment, that cannot be attributed to the properties of the placebo itself
- due to the patient's belief in the treatment
Describe 2 research design methods of controlling for placebo effects.
- blinded trials: subjects do not know whether or not they are receiving real or placebo treatment
- having a natural history group: receive no treatment
Describe additional factors, other than placebo effect, that can introduce unwanted
variation into research results and thus need to be controlled.
- random error (chance)
- systematic error (bias)
- measurement error (reliability and validity)
- misclassification (information bias)
- sampling error
- observer and instrument variation
- absent or inappropriate reference standard
- limited amount of evidence
Once an action potential reaches the axon terminals of an ______, it is ready to
trigger a muscle contraction
Describe all the steps of muscle contraction, starting at the axon terminals and ending with muscle relaxation.
- AP starts in brain
- AP arrives at axon terminal, releases ACh
- ACh crosses synapse, binds to ACh receptors on plasmalemma
- AP travels down plasmalemma, T-tubules
- triggers Ca 2+ release from SR
- Ca 2+ enables actin-myosin contraction
- AP ends, electrical stimulation of SR stops
- Ca2+ pumped back into SR
- without Ca2+, trooping and tropomyosin return to resting conformation
Describe the key structural and functional differences in the three major muscle fiber
.- Type I
peak tension in 110 ms
50% of fibres
Slower myosin ATPase = slower contraction cycling
Smaller neuron < fibres
- Type II
Peak tension in 50 ms (fast twitch).
25% of fibres each.
Fast myosin ATPase = fast contraction cycling
More highly developed SR
Faster Ca2+ release
Larger neuron >300 fibres
- different types of myosin
How do the differences in the 3 major muscle fibre types result in different exercise capabilities?
- high aerobic endurance
- low intensity aerobic exercise, daily activities
- more force, faster fatigue than type I
- short, high intensity endurance events
- seldom used for everyday activities
- short, explosive sprints
Describe the different methods that muscles use to increase the force of contraction.
- more force production: more or larger motor units (Type II)
- length-tension relationship (optimal sarcomere length)
- speed-force relationship (concentric: maximal force development decreases at higher speeds) (eccentric: maximal force development increases at higher speeds)
How much energy does a gram of each 3 major energy substrates yield?
- carb: 4.1 kcal/g
- fat: 9.4 kcal/g
- protein: 4.1 kcal/g
How are each 3 major energy substrates stored?
- all converted to glucose
- 2500 kcal stored in body
- extra glucose stored as glycogen in liver, muscles
- +70,000 kcal stored in body
- must be broken down into free fatty acids and glycerol
- must be converted into glucose
- can also convert into FFAs (energy storage)
When are each 3 major energy substrates preferentially used?
- carb: immediate
- fat: prolonged, less intense exercise
- protein: during starvation
Site of production for each of 3 metabolic pathways the body uses to generate ATP:
- all steps occur in cytoplasm
- occurs in mitochondria
ATP yield for each of 3 metabolic pathways the body uses to generate ATP:
- 1 mol ATP/1 mol PCr
- 2-3 mol ATP/1 mol substrate
- depends on substrate
- 32-33 ATP/1 glucose
- 100+ ATP/1 FFA
Duration for each of 3 metabolic pathways the body uses to generate ATP:
- 3 to 15 s
- 15s to 2 min
- steady supply for hours
Oxygen or substrate requirement for each of 3 metabolic pathways the body uses to generate ATP:
- phosphocreatine (PCr): ATP recycling
- uses glucose or glycogen
Corresponding optimal form(s) of exercise for each of 3 metabolic pathways the body uses to generate ATP:
- 3-15 s maximal exercise
- allows muscle to contract when O2 limited
- short term high intensity exercise
- 2 min maximal exercise
- long endurance
Describe the three ways in which lactate can be used as a fuel by the exercising muscle.
- lactate produced in cytoplasm can be taken up by the mitochondria of the same muscle fibre and oxidized
- lactate can be transported via MCP transporters to another cell and oxidized there (lactate shuttle)
- lactate can recirculate back to the liver, reconverted to pyruvate and then to glucose through gluconeogenesis
Outline the sequence of events that is thought to contribute to the development of
- high tension in muscle --> structural damage to muscle, cell membrane
- membrane damage disturbs Ca2+ homeostasis in injured fibre (inhibits cellular respiration, activates enzymes that degrade Z disks)
- after few hours, circulating neutrophils
- products of macrophage activity, intracellular contents accumulate (histamine, kinins, K+, stimulate pain in free nerve endings)
- fluid and electrolytes shift into the area creating edema
What exercise practices promote the development of DOMS?
- eccentric contracions
practices help avoid the development of DOMS?
.- minimize eccentric work early in training
- start with low intensity and gradually increase
- start with high intensity exhaustive training (soreness bad at first, much less later on)
Theory behind direct calorimetry:
- substrate metabolism efficiency
- 40% of substrate energy: ATP
- 60% of substrate energy: heat
- heat production increases with energy production
Theory behind indirect calorimetry:
estimates total body energy expenditure based on O2 used, CO2 produced
How is direct calorimetry measured?
- can be measured in a calorimeter
- water flows through walls
- body temperature increases water temperature
How is indirect calorimetry measured?
- measures respiratory gas concentrations
- haldane transformation
Pros of direct calorimetry:
- accurate over time
- good for resting metabolic measurements
Cons of direct calorimetry:
- expensive, slow
- exercise equipment adds extra heat
- sweat creates errors in measurements
- not practical or accurate for exercise
Pros of indirect calorimetry:
- CO2 production may not = CO2 exhalation
- RER inaccurate for protein oxidation
- RER near 1.0 may be inaccurate when lactate buildup inc. CO2 exhalation
- gluconeogenesis produces RER <0.70
Cons of indirect calorimetry:
- only accurate for steady state oxidative metabolism
Maximal oxygen consumption is often described as the most important variable for an exercise physiologist to know. Based on what you have learned about this variable so far, discuss whether you agree with this statement and why.
- best single measurement of aerobic fitness
- not the best predictor of endurance performance
- needs to be relative to body weight
How does the process of normal, quiet inhalation differ from that of forced inhalation?
How does the process of normal, quiet exhalation differ from that of forced exhalation?
Compare how oxygen and carbon dioxide are transported in the blood.
Changes that occur in HR from rest to max exercise. Why does this occur?
- directly proportional to exercise intensity
- max HR: highest HR achieved in all out effort to volitional fatigue
- steady state HR: point of plateau, optimal HR for meeting circulatory demands at a given sub maximal intensity
Changes that occur in SV from rest to max exercise. Why does this occur?
- inc. with inc. intensity up to 40-60% VO2 max
- beyond this S plateaus to exhaustion
- SV during maximal exercise = double standing SV
- SV during maximal exercise only slightly higher than supine SV
- increase in HR = dec. filling time = dec. SV
Changes that occur in cardiac output from rest to max exercise. Why does this occur?
- Q = HR x SV
- inc. with inc. intensity, plateaus near VO2 max
- Q max a function of body size and aerobic fitness
How does HR, SV, and cardiac output interact with each other to maintain adequate cardiovascular support for exercise?
- Fick principle
- calculation of tissue O2 consumption depends on blood flow, O2 extraction
- VO2 = HR x SV x (a-v)O2 difference
Discuss the major factors that contribute to an increase in muscle blood flow during
- inc. HR
- inc. SV
- inc. Q
- Inc. BP (MAP)
- redirect inc. blood flow to areas with greater metabolic need
- sympathetic vasoconstriction shunts blood away from less active regions
Discuss the five general principles of training and how each of them must be considered when designing an overall training plan.
Advantages of free-weight resistance training:
Disadvantages of free-weight resistance training:
Advantages of machine resistance training:
Disadvantages of machine resistance training:
When is free weight resistance training appropriate?
When is machine resistance training appropriate?
What are the major criteria involved in designing an anaerobic or aerobic interval training program?
How should each criterion for anaerobic or aerobic interval training program be treated for a sprinter compared to a
Discuss to what extent fiber hypertrophy and fiber hyperplasia contribute to chronic muscle hypertrophy in humans.
Explain how immobilization and detraining contribute to muscle atrophy.
- immediate and more pronounced muscle loss
- injury or disease that affects the nerves that connect connective muscle tissue
Explain the reasons older adults have decreased muscle mass compared to when they were younger.
- physically inactive people can lose as much as 3-5% muscle mass each decade after age 30
- lower concentration of some hormones
- decrease in the ability to turn protein into energy
- not getting enough calories or protein
- reduction in nerve cells responsible for sending signals from the brain to the muscles to start movement
After chronic endurance training, how do the adaptations that occur in muscle complement the adaptations that occur in metabolic function, which together help enable aerobic capacity and performance to improve?
What kinds of muscular adaptations occur after anaerobic training that lead to improved anaerobic performance?
- inc. in type IIa, IIx cross sectional area
- inc. in type I cross sectional area
- dec. % of type I fibres, inc. % of type II
Compare and contrast overreaching and overtraining. How are the two approaches and conditions similar? How are they different?
- overreaching is an acute condition that can lead to overtraining (chronic)
- recovery time is different
- overreaching is not necessarily a bad thing
What are the red flags that a coach would look for to spot overtraining syndrome in one
of his or her athletes?
- unexplained decrease in performance, function for weeks, months or years
- strength, coordination, capacity
- change in appetite, weight loss
- sleep and mood disturbances
- lack of motivation, vigor, and/or concentration
Treatment for overtraining syndrome:
- reduced intensity of rest (weeks, months)
- conselling to deal with stress
What are the key differences between tapering and detraining?
- brief period = tapering
- longer period = detraining
- reduction in training (volume/intensity) = tapering
- does not result in deconditioning = tapering
- leads to improved performance = tapering
- immobilization = detraining
- significant cardiorespiratory losses = detraining
Hallmarks of the 3 major developmental stages that mark human growth and development between birth and adulthood:
What events and milestones divide one stage from the next for the 3 major developmental stages that mark human growth and development between birth and adulthood?
Compare the cardiovascular responses to a single bout of submaximal aerobic exercise
between a child and an adult. Why are some variables similar and others different?
- child max HR higher than in adults
- child max SV lower than in adults
Explain how strength gains occur in children engaged in a resistance training program.
strength gains only via neural mechanisms, no hypertrophy
Explain how strength gains occur in adolescents in a similar training program.
.neural + hypertrophy
Discuss the physiological factors that limit maximal oxygen uptake in older populations.
- dec. VO2 max with age due to dec. Q max
- dec. vital capacity and FEV1
- inc. residual volume
- less air exchanged
- dec. lung and chest wall elasticity
Discuss the thermoregulatory risks of exercise that are exacerbated by advancing age. Why are older people more prone to these issues?
- higher risk of death from hyperthermia
- higher core temp.
- metabolic heat gain related to absolute VO2
- heat loss related to relative percent VO2max
- physical training improves skin vasodilation, sweat rate, redistribution of Q
Discuss why women (on average) have a different VO max than men. Is it higher or lower? What factors contribute to this difference?
- women's VO2 max < men's VO2 max
- women's lower hemoglobin limits VO2 max
- women's lower cardiac output limits VO2 max (heart size, plasma volume)
- peak lactate concentrations lower in women
What factors cause menstrual cycle disruption in female athletes? What are the implications?
- delayed menarche in certain sports (past age 14) due to decreased fat composition
- menstrual dysfunction in lean-physique sports
- secondary amenorrhea (energy deficit, inadequate caloric intake)
Discuss the various health complications and health risks that arise from overweight and obesity.
- cardiovascular disease
- type 2 diabetes
- liver, gallbladder disease
- sleep apnea
- orthopaedic problems
- increased mortality