Final Review Flashcards
(75 cards)
Provide an example of what is meant by studying acute responses to a single bout of
exercise.
- instantaneous
- 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?
- feasibility
- 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:
- portable
- 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
α-motor neuron
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
types.
.- 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?
Type I - high aerobic endurance - low intensity aerobic exercise, daily activities Type IIa - more force, faster fatigue than type I - short, high intensity endurance events Type IIx - 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?
Carbs
- all converted to glucose
- 2500 kcal stored in body
- extra glucose stored as glycogen in liver, muscles
Fat
- +70,000 kcal stored in body
- must be broken down into free fatty acids and glycerol
Protein
- 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:
ATP-PCR system ? Glycolytic System - all steps occur in cytoplasm Oxidative System - occurs in mitochondria
ATP yield for each of 3 metabolic pathways the body uses to generate ATP:
ATP-PCR system - 1 mol ATP/1 mol PCr Glycolytic system - 2-3 mol ATP/1 mol substrate Oxidative System - 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:
ATP-PCR system - 3 to 15 s Glycolytic System - 15s to 2 min Oxidative System - steady supply for hours
Oxygen or substrate requirement for each of 3 metabolic pathways the body uses to generate ATP:
ATP-PCR system - phosphocreatine (PCr): ATP recycling Glycolytic System - uses glucose or glycogen Oxidative System - glucose - FFA