Exercise Physiology Unit 4

Which of the following statements are true about the effect of endurance training or detraining on mitochondria volume in human skeletal muscle?

-Five weeks of endurance training can increase skeletal muscle mitochondrial volume by two times about normal. -Seven days of detraining can reduce mitochondrial volume by 50% below the trained level. -After a period of detraining, approximately 4 weeks of retraining is required to regain the lost mitochondrial volume. -All of these are true.***

Which of the following training adaptations does NOT occur in skeletal muscles following 4-10 weeks of anaerobic exercise training?

-increased muscle buffer capacity -increased activities of myokinase and creatine phosphokinase -increased activities of key glycolytic enzymes -None of these answers is correct***

The enhanced capacity of the trained muscle to use fatty acids as a fuel results in

-increased uptake of fatty acids. -decreased utilization of muscle glycogen. -sparing of blood glucose. -all of these answers are correct.***

Increased production of radicals in skeletal muscles during periods of prolonged inactivity (prolonged bedrest) and promotes muscle atrophy because:

-oxidative stress activates proteases in muscle fibers -oxidative stress decreases protein synthesis in muscle fibers -oxidative stress prevents mTOR activation -All of these are correct***

Endurance exercise training programs (e.g., 3 days/week @ 60% VO2 max for 12 weeks) typically results in a ______.

15-25% improvement in VO2 max

Four-to-ten weeks of anaerobic training (high intensity exercise lasting 10-30 seconds) can increase the peak anaerobic capacity by ______ across individuals.

3-25%

Blood buffers would most likely improve performances lasting

30 to 180 seconds.

Following a single bout of resistance exercise training, muscle protein synthesis can remain elevated above sedentary levels for as much as ______ in both trained and untrained individuals.

35-50 hours

The average VO2 max value for the young (e.g., 21 years old) male sedentary population is approximately

45 ml • kg-1 • min-1.

Heritability (i.e., genetics) determines approximately _____% of VO2 max variability in sedentary adults.

50

High responders to endurance exercise training (i.e., individuals that achieve large increases in VO2 max) can achieve up to ______% improvement in VO2 max following a prolonged and intense training program.

50

A single bout of resistance exercise training increases muscle protein synthesis by as much as ______% above resting levels?

50-150

It is estimated that _______% of the differences in muscle mass between individuals can be explained by genetic variation.

80

Which of the following factors DO NOT contribute to the decline in VO2 observed during 84 days of detraining?

A decrease in maximal heart rate

In theory, concurrent resistance and endurance exercise training can impair muscle protein synthesis following a bout of resistance exercise. The proposed mechanism to explain this inhibition is _____________________________________.

AMP kinase activation of TSC2

The addition of myonuclei to growing muscle fibers ______________.

Both appears to be essential for optimal muscle hypertrophy in response to resistance training and is likely required to maintain the high level of transcriptional capacity needed to synthesize muscle proteins and allow muscle fibers to grow during resistance training are correct

During the first four months of an endurance exercise training program, the initial increase in VO2 max is primarily due to

Both increases in stroke volume and increases in maximal cardiac output are correct.

Daily supplementation with high doses of the antioxidant vitamins C and E can

Both provide limited protection against exercise-induced muscle fatigue and depress exercise-induced training adaptations in skeletal muscles are correct.

Which of the following statements about resistance training is NOT true?

Resistance training DOES NOT promote hypertrophy and strength gains in people greater than 65 years old.

Several factors contribute to neural drive. Which one of the following factors is NOT a contributor to neural drive?

activation of the Golgi tendon organ

Which of the following has been shown to interfere with cross-bridge "cycling" during exercise?

an accumulation of H+

A muscle (i.e., prime mover) that results in movement of a limb in the desired direction is labeled as _____________.

an agonist

Fatigue refers to

an inability to maintain power output during repeated contractions.

Resistance training results in an increase in the rate of contractile protein synthesis which is matched by _________________.

an increase in the synthesis of collagen in tendons and ligaments

The term hyperplasia refers to ________________.

an increase in the total number of muscle fibers

Prolonged inactivity of skeletal muscle leads to rapid muscle atrophy; this occurs due to:

both a decrease in muscle protein synthesis and increased protein breakdown in muscle fibers are correct

The increase in VO2 max that occurs following 16 months of endurance exercise training results from

both an increase in the maximal a-vO2 difference and an increase in maximal cardiac output are correct.

A subject, with eyes closed, repeatedly contracts a muscle until fatigue occurs. When the eyes are opened, the muscle's ability to produce force is improved. This experiment is a demonstration of fatigue being linked to which of the following sites?

central nervous system

Which of the following are essential factors in the successful completion of an ultra-endurance event?

having trained the body to markedly shift to fat oxidation to fuel the work performed during the ultra-endurance competition

A single bout of resistance exercise training results in an increase in skeletal muscle protein synthesis. This exercise-induced increase in muscle protein synthesis can occur within _____ following the exercise session.

hours

Following an acute bout of endurance exercise training, the increase in mitochondrial biogenesis occurs within _____ following the completion of the exercise session.

hours

Which of the following factors DO NOT contribute to the endurance exercise training-induced increases in fat metabolism during exercise?

increased fat storage in the liver

Which of the following endurance training adaptations does NOT result in lower lactate production in the contracting muscles?

increased glycogen utilization

Which of the following physiological factors does NOT contribute to the endurance exercise training-induced increase in the maximal a-vO2 difference?

increased hemoglobin in the blood

Which of the following factors do not contribute to the endurance exercise training-induced improvement in VO2 max?

increased maximal heart rate

Which of the following endurance training adaptations assist in maintaining acid-base balance during exercise?

increased mitochondrial volume in skeletal muscle

Which of the following factors does NOT contribute to the endurance exercise training-induced improvement in stroke volume during exercise?

increased peripheral resistance

Endurance training has been shown to reduce the oxygen deficit in subjects performing a bout of submaximal exercise. This is likely due to

increases in the number of mitochondria and capillaries.

A major regulator of protein synthesis and muscle size is ____________.

mTOR

Following an acute bout of endurance exercise training, the rise in the activity of calcinuneurin, calmodulin kinase, and AMP kinases occurs within _____ following the exercise session.

minutes

Endurance exercise training results in an increase in mitochondria volume within skeletal muscle fibers. The process of synthesizing mitochondria in cells is called ______.

mitochondrial biogenesis

The removal of damaged mitochondria in skeletal muscle and other cells is called

mitophagy.

The phenomenon that previous strength training accelerates the re-acquisition of both muscular strength and hypertrophy is commonly referred to as _________.

muscle memory

During the first 8 weeks of a resistance training program, the initial increase in muscular strength is primarily due to

neural adaptations.

Muscles receive a neural activation signal from motor neurons located in the spinal cord. This neural signal is referred to as ________.

neural drive

In examining the mechanisms for exercise-induced fatigue, the vast majority of the evidence points to the

periphery (i.e., peripheral fatigue).

It is established that resistance exercise training promotes an increase in muscle protein synthesis by activating the mechanistic target of rapamycin (mTOR) which results in increased protein synthesis. Recent evidence suggests that two signaling molecules interact to directly activate mTOR. These molecules are:

phosphatidic acid and Ras homologue enriched brain (Rheb)

Aging is associated with a decline in strength, with most of the decline occurring after age 50. The loss of strength is due, in part, to a loss of muscle mass; this age-related loss of muscle mass is termed

sarcopenia.

Studies suggest that elevating the levels of _____________ in the brain can contribute to "central" fatigue during prolonged endurance events.

serotonin (5-hydroxytryptamine)

By comparison to the rate of detraining following endurance training, the rate of detraining (i.e., loss of muscular strength) following a resistance training program is _________.

slower

Endurance training results in increased mitochondrial and capillary density in muscle but has no effect on muscle glycolytic capacity. This is an example of what training principle?

specificity

Which of the following are not potential mechanisms of peripheral fatigue?

spinal cord activation

Cross-sectional studies demonstrate that the physiological variable responsible for the large variation in VO2 max across the normal (untrained) population is maximal

stroke volume.

Several hormones have the potential to increase muscle protein synthesis. These include:

testosterone, insulin-like growth factor-1 (IGF-1), and growth hormone

An important physiological factor that may contribute to the inhibition of motor unit activation during resistance training is ____________.

the Golgi tendon organ

Growing evidence reveals that, independent of resistance exercise, ____________ can activate mTOR and promote small increases in muscle protein synthesis.

the amino acid leucine

Following several weeks of endurance exercise training, the capacity to transport glucose into skeletal muscle fibers is increased. Which of the following training-induced changes contribute to this training effect?

the increase in the number of GLUT4 glucose transporters

Neural drive is defined as ___________________________________.

the magnitude of the efferent neural output from the central nervous system to the motor units and the muscle fibers that they activate

The term cross-education refers to ___________________.

the observation that if one limb engages in resistance training, muscular strength increases in the untrained (contralateral) limb

Research indicates that following a series of voluntary contractions to produce skeletal muscle fatigue, electrical stimulation of the "fatigued" muscle group results in an increase in the maximal voluntary force production. This experiment suggests that:

the upper limit of voluntary strength is psychologically set and that the central nervous system can limit performance.

The heart rate and ventilatory responses to constant load submaximal exercise are lower (i.e., lower heart rate and lower minute ventilation) following an endurance training program. This training-induced adaptation is primarily due to changes in the

trained skeletal muscles.

In resting skeletal muscle fibers, Ras homologue enriched brain (Rheb) activation of mTOR is inhibited by ______.

tuberous sclerosis complex 2 (TSC2)

Research reveals that resistance training induced muscle hypertrophy is associated with an increase in myonuclei. The source of these additional myonuclei is _____________.

via satellite cell activation