McArdle Ch.21 Flashcards
what is specificity principle(1)
refers to adaptations in metabolic and physiologic functions that depend upon the type and mode of overload imposed
What is the most effective way to evaluate a sport specific performance?
when the laboratory measurement most closely simulates the actual sport activity and/or uses the muscle mass and movement patterns required by the sport
what does SAID stand for and y is it important?
refers to Specific Adaptations to Imposed Demands
it stipulates that if your are only training one region, that region will be the only to improve.
ex:on the bike then your LE would improve and also consume more O2 than the UE
What is specificity of VO2?
When training for specific aerobic activities, the overload must:
- Engage the appropriate muscles required by the activity
- Provide exercise at a level sufficient to stress the cardiovascular system
How do you get the greatest improvement in VO2?
Little improvement occurs when measuring aerobic capacity with dissimilar exercise;
the greatest improvement occurs when the test exercise duplicates the training exercise
What is specificity of local changes?
Overloading specific muscle groups with endurance training enhances exercise performance and aerobic power by facilitating oxygen transport and oxygen use at the local level of the trained muscles
These adaptations occur only in specifically trained muscles and only become apparent in exercise that activates this musculature
Where is there a greater blood flow in active tissue during specificity of local changes?
May result from greater blood flow in active tissues from:
Increased microcirculation
More effective redistribution of cardiac output
The combined effect of both factors
What is the individual difference principle(2)?
All individuals do not respond similarly to a given training stimulus
Optimal training benefits occur when exercise programs focus on the individual needs and capacities of participants
what is the reversibility principle?
Only 1 or 2 weeks of detraining reduces both metabolic and exercise capacity, with many training improvements fully lost within several weeks
How do athletes combat the reversibility principle?
Most athletes begin a reconditioning program several months prior to the start of the competitive season or maintain some moderate level of off-season, sport-specific training to slow the decline
How do anaerobic system change with training?
- Increased levels of anaerobic substrates
- Increased quantity and activity of key enzymes that control the anaerobic phase of glucose catabolism
- Increased capacity to generate high levels of blood lactate during all-out exercise, resulting from:
- Increased levels of glycogen and glycolytic enzymes
- Improved motivation and tolerance to “pain” in fatiguing physical activity
What is the difference between regular muscle fibers and endurance trained ones?
Endurance-trained skeletal muscle fibers contain larger and more numerous mitochondria than less active fibers:.
- This will increase the muscle’s ability to extract oxygen which consequently improves the a-vO2diff
- This greatly increases the capacity of the muscle mitochondria to generate ATP
How does endurance training affect fatty acids?
Endurance training increases the oxidation of fatty acids for energy during rest and submaximal exercise
What are the factors that contribute to a heightened training-induced increased lipolysis?
- Greater blood flow within a trained muscle
- More fat-mobilizing and fat-metabolizing enzymes
- Enhanced muscle mitochondrial respiratory capacity
- Decreased catecholamine release for the same absolute power output
Trained muscle exhibits enhanced capacity to oxidize carbohydrate during ___?
maximal exercise
Reduced carbohydrate as fuel and increased fatty acid combustion in submaximal exercise with endurance training results from the combined effects of the following?
Decreased muscle glycogen use
Reduced glucose production
Reduced use of plasma-borne glucose
Aerobic training elicits ____ in all types of muscle fiber
metabolic adaptations
what is the difference between highly trained endurance athletes and randoms twitch fibers?
Highly trained endurance athletes have larger slow-twitch fibers.
what are slow-twitch muscle fibers?
Slow-twitch muscle fibers with a high capacity to generate ATP aerobically contain relatively large quantities of myoglobin
what are fast-twitch fibers?
The fast-twitch fibers of athletes trained in anaerobic power activities occupy a greater portion of the muscle’s cross-sectional area
How does long-term aerobic training affect athletes’ hearts?
Long-term aerobic training increases the heart’s mass and volume with greater left-ventricular end-diastolic volumes during rest and exercise
This enlargement is characterized by eccentric hypertrophy and to some extent concentric hypertrophy
Endurance athletes average a __% larger heart volume than sedentary counterparts
25%
bc Training duration affects cardiac size and structure
What is the difference between an enlarged heart during exercise and an enlarged heart bc of disease?
The disease can induce considerable cardiac enlargement and this “hypertrophied” heart represents an enlarged, distended, and functionally inadequate organ unable to deliver sufficient blood to satisfy minimal resting requirements
Exercise training imposes only a temporary myocardial stress so rest periods provide time for “recuperation” and demonstrates normal systolic and diastolic functions and superior functional capacity for stroke volume and cardiac output
How does plasma volume change during aerobic training?
- A 12-20% increase in plasma volume occurs after three to six aerobic training sessions
- A plasma volume increase enhances circulatory reserve and increases end-diastolic volume, stroke volume, oxygen transport, VO2max, and temperature regulation during exercise
- An expanded plasma volume returns to pretraining levels within 1 week following detraining
How does aerobic training effect the heart rate?
Training decreases the intrinsic firing rate of sinoatrial nodal pacemaker tissue, contributing to the resting and submaximal exercise bradycardia in highly conditioned endurance athletes or previously sedentary individuals who train aerobically
->Submaximal heart rate for a standard
exercise task frequently decreases by 12-15 bpm with endurance training,
while a much smaller decrease occurs
for resting heart rate
-this reduction coincides with increased max stroke volume and cardiac outpout
How is SV affected during exercise?
Endurance training causes the heart’s stroke volume to increase during rest and exercise regardless of age or gender
what are the factors that produce a change in SV?
- Increased internal left ventricular volume and mass
- Reduced cardiac and arterial stiffness
- Increased diastolic filling time
- Improved intrinsic cardiac contractile function
Difference btw trained and untrained SV?
- Endurance athletes’ hearts exhibit a considerably larger stroke volume during rest and exercise
- The greatest stroke volume increase during upright exercise for trained and untrained occurs in the transition from rest to moderate exercise
- Maximum stroke volume occurs between 40-50% of VO2max in untrained persons
- For untrained individuals, only a small increase in stroke volume occurs during the transition from rest to exercise
- For endurance athletes, heart rate and stroke volume both increase to increase cardiac output
What happens to CO during exercise?
An increase in maximum cardiac output is the most significant cardiovascular adaptation with aerobic training
:.Results directly from improved stroke volume
What’s peculiar about CO for trained athletes?
In trained athletes, cardiac output increases linearly with oxygen consumption throughout the major portion of the exercise intensity range
Submax exercise CO is unchanged or slightly lower from?
- Rapid training-induced changes in vasoactive properties of large arteries and local resistance vessels within skeletal and cardiac muscle
- Muscle cells enhance their capacity to generate ATP at a lower tissue PO2
Maximal exercise CO increases because of?
- Larger maximal cardiac output (mainly SV)
- Distribution of blood to muscle from non-active areas
- Enlargement of cross-sectional areas of arteries and veins, 20% increase in capillarization/gram of muscle
Aerobic training ____ the quantity of oxygen extracted from circulating blood
increases
Aerobic training increases the quantity of oxygen extracted from circulating blood results for:
more effective cardiac output distribution to active muscles combined with enhanced capacity of trained
muscle fibers to extract and process available oxygen
What are vascular modifications?
An increase in cross-sectional area of proximal coronary arteries, possible arteriolar proliferation and longitudinal growth, recruitment of collateral vessels, and increased capillary density
which provides adequate perfusion for increased blood flow and energy demands
Aerobic training increases coronary blood flow and capillary exchange capacity from?
- Improvements in myocardial vascularization by the formation of capillaries that develop into arterioles
- More effective control of vascular resistance and blood distribution within the myocardium
How does exercise affect blood pressure?
Regular aerobic training reduces systolic and diastolic blood pressure during rest and submaximal exercise
When is there the largest reduction of pressure during exercise happen?
The largest reduction occurs in systolic pressure, particularly in hypertensive subjects
What are the factors that affect aerobic training responses?
The initial level of aerobic fitness
Training intensity
Training frequency
Training duration
(FITT)
How does the initial level of aerobic fitness affect future training?
The magnitude of the training response depends on the initial fitness level
- Someone who rates low at the start has considerable room for improvement
- If capacity already rates high, the magnitude of improvement remains relatively small
aerobic fitness improvements with endurance training range btw 5-25%
Training-induced adaptations rely on intensity of ____
overload
How does aerobic capacity affect HR?
Aerobic capacity improves if exercise intensity regularly maintains heart rate between 55 and 70% of maximum
-During lower-body exercise, this heart rate increase equals about 40-55% of the VO2max
what is the Karvoven method>
HRthreshold =HRrest+0.60(HRmax - HRrest)
To keep pace with physiologic improvement as aerobic fitness improves, the exercise level must _____ to achieve the desired exercise heart rate
increase periodically
If exercise intensity progression does not adjust to training improvements, the exercise program essentially becomes a ____ program
lower-intensity maintenance
How is HR different during running and swimming?
HRmax during swimming or performing other upper-body exercises averages about 13 bpm lower for trained and untrained men and women than while running
Why is HRmax during swimming about 13 bpm lower than while running?
- Less feed-forward stimulation from the motor cortex to the medulla during swimming
- Less feedback stimulation from the smaller, active upper-body muscle mass
- The horizontal body position and cooling effect of the water in swimming
- Central venous pressure
Exercising at or slightly above the lactate threshold:
The higher exercise levels produce the greatest benefits, particularly for fit individuals
Distinctions between %HRmax and lactate threshold:
- %HRmax method establishes a level of exercise stress to overload the central circulation
- Exercise intensity from the lactate threshold reflects the capability of the peripheral vasculature and active muscles to sustain steady-rate aerobic metabolism
Based on the specificity concept, the magnitude of training improvement varies considerably depending on ___ and ___
training and testing mode
What is the time required for improvements to occur in aerobic exercise?
- Improvements in aerobic fitness occur within several weeks
- BUT Adaptive responses eventually level off as subjects approach their “genetically predisposed” maximums
How do genes affect components of exercise?
A strenuous exercise program enhances a person’s level of fitness regardless of genetic background
HOWEVER: The limits for developing fitness capacity appear to link closely to natural endowment
think of the twin example: although one has always been active and the other is a couch potato, they both processed the same genes and had similar results.
Factors in formulating aerobic train:
- Cardiovascular overload must be intense enough to increase stroke volume and cardiac output
- Cardiovascular overload must occur from activation of sport-specific muscle groups to enhance local circulation and the muscle’s “metabolic machinery”
what is overtraining?
Represents when athletes fail to endure and adapt to training so that normal exercise performance deteriorates, and they encounter increasing difficulty fully recovering from a workout
what does overtraining lead to?
to increased incidence of infections and injuries, persistent muscle soreness, and general malaise and loss of interest in sustaining high-level training
Two clinical forms of overtraining have been described:
Sympathetic form
Parasympathetic form
Overload:
A planned, systematic, and progressive increase in training to improve performance
Overreaching:
Unplanned, excessive overload with inadequate rest. Poor performance is observed in training and competition. Successful recovery should result from short-term interventions
Overtraining syndrome:
Untreated overreaching that produces long-term decreased performance and impaired ability to train. Other associated problems may require medical attention.
