Exercise Physiology Exam 3

Define the Frank-Starling mechanism. How does this work during exercise?

The heart pumps out whatever blood returns to it
During exercise there is an increase in left ventricular EDV, which increases SV

What happens to heart rate during exercise?

Increases almost linearly with exercise intensity

What happens to cardiac output during exercise?

Increases linearly to with exercise intensity, potentially reaching a plateau at maximal exercise intensity

What happens to blood pressure during exercise?

Systolic increases with intensity, diastolic remains the same or slightly decreases

What happens to plasma volume during exercise?

Decreases during exercise because fluid moves into tissues and sweat is produced

What happens to hemoconcentration during exercise?

Decrease in plasma volume causes hemoconcentration
Increases concentration of red blood cells and other blood components improving the blood’s oxygen carrying capacity

What is the Fick Principle?

The oxygen consumption of a tissue is dependent on blood flow to that tissue and the amount of oxygen extracted from the blood by the tissue.

What is cardiovascular drift and what causes it?

When SV gradually decreases and HR increases with prolonged aerobic exercise
Caused by dehydration, reduced plasma volume, higher body temperature

How does blood flow redistribution occur during exercise and why?

During exercise sympathetic nervous system activation causes vasoconstriction in inactive tissues and vasodilation in active skeletal muscles and the heart
This ensures oxygen and nutrients are delivered where they are needed most

Explain the central regulation of the cardiovascular response during exercise.

The cardiovascular response to exercise is controlled by the cardiovascular control center in the medulla oblongata
Signals from the motor cortex, mechanoreceptors, chemoreceptors, and baroreceptors adjust sympathetic and parasympathetic activity to regulate heart rate, stroke volume, blood pressure, and blood flow.

Compare ventilation during low, moderate, and intense exercise.

Pulmonary ventilation immediately increases at the onset of exercise and before the onset of muscular contractions as anticipatory response. Pulmonary ventilation increases during exercise in direct proportion to the metabolic needs of exercising muscle

What is dyspnea?

Shortness of breath that occurs during exercise or in people with respiratory disorders

What is hyperventilation?

An increase in ventilation in excess of that needed to support exercise

What is the valsalva maneuver?

This occurs when the individual closes the glottis, increases the intra-abdominal pressure, and increases the inthrathoracic pressure
Dangerous respiratory procedure that accompanies the lifting of heavy objects

What is ventilatory threshold and how does it relate to anaerobic and lactate threshold?

The point at which ventilation increases disproportionately to oxygen consumption during exercise

It occurs because increased lactate production leads to greater carbon dioxide production through buffering, stimulating ventilation (aka anaerobic threshold)

How does the respiratory system regulate acid-base balance during exercise?

As exercise intensity increases, hydrogen ions accumulate from lactate production. Bicarbonate buffers these hydrogen ions, producing carbon dioxide. Increased ventilation removes the excess carbon dioxide, helping maintain blood pH.

Why is active recovery better than passive recovery?

Active recovery maintains light muscle activity, improving blood flow and accelerating the removal of lactate and metabolic byproducts. This allows the body to recover more quickly than complete rest.

Explain the differences between muscular strength, power, and endurance.

Strength = the maximal force that a muscle or muscle group can generate
Power = the rate at which work is performed, the product of force and velocity
Endurance = the capacity to perform repeated muscle contractions, or to sustain a contraction over time

Define the Principle of Individuality.

Every person responds differently to training because of genetics, age, sex, health, and training history

Define the Principle of Specificity.

Exercise adaptations are specific to the muscles used, mode, intensity, and duration of training

Define the Principle of Reversibility

If training is decreased or stopped, the physiological adaptations that caused the improvements in performance will be reversed

Define progressive overload.

Fitness improves only when the body is challenged with workloads greater than those it is accustomed to

Define variation.

Training programs should vary exercises, intensity, and volume over time to prevent plateaus and reduce injury risk

Explain strength training.

Uses heavy loads with low repetitions to maximize force production

Explain hypertrophy training.

Uses moderate to heavy loads with moderate repetitions to increase muscle size

Explain power training.

Combines strength and speed using explosive movements

Explain static-contraction resistance.

Involves isometric contractions without joint movement

Explain free weights vs machines.

Free weights require greater stabilization and mimic functional movements, whereas machines provide more stability and isolate specific muscles

Explain dynamic eccentric training.

Focuses on controlled muscle lengthening and produces high force while improving strength

Explain variable-resistance training.

Uses elastic bands or specialized equipment that changes resistance throughout the movement

Explain isokinetic training.

Uses specialized equipment that keeps movement speed constant while resistance varies

Explain plyometrics.

Stretch–shortening cycle exercise using the stretch reflex to facilitate recruitment of motor units

Explain electrical stimulation.

Uses electrical currents to stimulate muscle contractions, often during rehabilitation

Explain core training.

Strengthens the muscles of the abdomen, lower back, pelvis, and hips to improve stability and performance

Explain the variables of interval training and how they affect performance.

Rate = determines the difficulty of each interval

Distance = how long work interval lasts

Reps/sets = total training volume

Duration = how long work interval lasts

Type of activity = matches athlete’s sport

Frequency = how often intervals are performed

How do we determine heart rate max (HRmax)?

HRmax = 220 − Age

Explain continuous training.

Involves exercising at a steady intensity for an extended period and improves aerobic endurance

Explain long slow distance (LSD) training.

Uses prolonged, low-intensity exercise to build cardiovascular endurance and enhance fat metabolism

Explain Fartlek training.

Alternates fast and slow running without fixed intervals, improving both aerobic and anaerobic fitness

Explain interval circuit training.

Combines resistance exercises with aerobic intervals, improving muscular endurance and cardiovascular fitness simultaneously

Explain HIIT training.

Alternates brief periods of near-maximal exercise with recovery periods, improving aerobic capacity and anaerobic performance

List the mechanisms of gains in muscle strength

Neural control

Motor unit recruitment

Rate coding

Autogenic inhibition

Hormones

Muscle hypertrophy

Define transient hypertrophy.

The increased muscle size that develops during and immediately following a single exercise bout

Define chronic hypertrophy.

The increase in muscle size that occurs with long-term resistance training

Define fiber hypertrophy.

An increase in the size of existing individual muscle fibers

Define fiber hyperplasia.

An increase in the total number of muscle fibers within a muscle, caused by resistance training

What are the recommendations for protein intake for people over 18 years of age, regardless of physical activity status?

Approximately 0.8 g/kg(body weight)/day

What are the recommendations for protein intake for athletes engaged in resistance training?

1.2–2.0 g/kg(body weight)/day

How many grams of protein should an individual consume immediately after

resistance training?

20–25 grams of high-quality protein

What is mTOR? What stimulates mTOR?

mTOR is the primary cellular signaling pathway that regulates muscle protein synthesis and hypertrophy
Resistance exercise and amino acid availability stimulate mTOR activity

Which specific amino acid will increase mTOR more than acute exercise alone?

Leucine

What are the benefits of resistance training for children and adolescents, elderly and sport populations?

Children and adolescents = improves muscular strength, bone density, coordination, and injury prevention

Elderly = increased muscle mass, improved balance, and reduced fall risk
Athletes = improve strength, power, sport performance, and resistance to injury

What are the differences in resistance training for children and adolescents?

Resistance training programs for children are prescribed in a very similar way as for adults, however there is an emphasis on teaching proper lifting technique

What are the differences in resistance training for elderly and sport populations?

Older adults should progress gradually while focusing on functional strength and balance

Athletes tailer resistance training to meet demands of their sport

Explain atrophy and how inactivity/immobilization and detraining affect muscular strength.

Atrophy = the loss of muscle size due to decreased protein synthesis and increased protein breakdown

Inactivity/immobilization = cause rapid declines in muscle mass, strength, and neural activation

Detraining = reverses many of the adaptations gained through training

Describe fiber type alterations (i.e., which fibers will change and under what conditions).

Resistance training causes the greatest hypertrophy in type II muscle fibers

Type IIx fibers often shift toward the more fatigue-resistant type IIa phenotype with training

Endurance training increases oxidative capacity within fibers but generally does not convert type I fibers into type II fibers

Describe heart size adaptation to aerobic training.

Increases heart size

Describe SV adaptation to aerobic training.

Increases stroke volume

Describe HR adaptation to aerobic training.

Resting and submaximal heart rates decrease

Describe Q adaptation to aerobic training.

Increases maximal cardiac output

Describe blood flow adaptation to aerobic training.

Increases blood flow to active muscles

Describe BP adaptation to aerobic training.

Resting and submaximal blood pressure are reduced

Describe blood volume adaptation to aerobic training.

Increased blood volume

Describe RBC volume adaptation to aerobic training.

Increased red blood cell volume

Describe the major respiratory system adaptations to aerobic training, including pulmonary ventilation, pulmonary diffusion, a-v O2 difference.

Aerobic training improves pulmonary ventilation during maximal exercise, increases pulmonary diffusion capacity, and enhances the a-v O2 difference by allowing muscles to extract more oxygen from the blood.

Explain the muscular adaptations to aerobic training, including fiber type, capillaries, myoglobin, mitochondrial function, enxymes.

Aerobic training increases capillary density, myoglobin content, mitochondrial number and size, oxidative enzyme activity, and the muscles' ability to use oxygen. Muscle fiber type remains largely unchanged, although type IIa fibers become more oxidative.

Explain the metabolic adaptations to aerobic training, including lactate threshold, RER, resting and submax VO2, max VO2.

Aerobic training raises lactate threshold, lowers (RER) at submaximal exercise by increasing fat utilization, decreases VO2 during submaximal exercise due to improved efficiency, and increases VO₂max.

Explain adaptations to anaerobic training, including in muscle, ATP-PCr system, glycolytic system

Anaerobic training increases ATP-PCr stores, glycolytic enzyme activity, muscle buffering capacity, and the muscles' ability to rapidly generate ATP during high-intensity exercise.

What is the difference between high responders and low responders?

In identical training programs:

High responders = showing large improvement

Low responders = showing little or no improvement

Explain the benefits of specificity of training and cross-training.

Specificity of training = training adaptations are greatest when exercise closely matches the movement patterns, muscles, and energy systems used in the desired activity
Cross-training = different exercise modes to maintain fitness, reduce overuse injuries, and provide training variety

Describe how heart rate, stroke volume, and cardiac output respond to increasing rates of work. Illustrate how these three variables are interrelated.

Heart rate increases directly in proportion to the increase in exercise intensity until near-maximal exercise is achieved. Stroke volume increases with increasing exercise intensity up to intensities somewhere between 40% and 60% of VO2max, where stroke volume then plateaus. Cardiac output also increases linearly to an increase in exercise intensity, potentially reaching a plateau at maximal exercise intensity. These are all interrelated because they create adjustments during exercise in order to increase blood flow to working muscle.

How do we determine HRmax?

The maximal heart rate is the highest HR value achieved in an all-out effort to the point of volitional fatigue. Sometimes an exercise test to maximal exertion may not be feasible, so there is also an equation to predict maximal heart rate using age to estimate. HRmax = 220 − age (years).

What is the Fick principle?

The Fick principle states that the oxygen consumption of a tissue is dependent on blood flow to that tissue and the amount of oxygen extracted from the blood by the tissue.

Define the Frank-Starling mechanism. How does this work during exercise?

The Frank-Starling mechanism states that the force of ventricular contraction increases as the heart muscle is stretched because as the ventricle fills with more blood, it stretches and subsequently contracts more forcefully. When someone goes from resting conditions to exercise of increasing intensity, there is an increase in left ventricular EDV, which increases SV through the Frank-Starling mechanism.

What is cardiovascular drift?

Cardiovascular drift is when SV gradually decreases and HR increases with prolonged aerobic exercise or aerobic exercise in a hot environment at a steady-state intensity. Cardiac output is well maintained, but arterial blood pressure also declines.

How does pulmonary ventilation respond to increasing intensities of exercise?

Pulmonary ventilation immediately increases at the onset of exercise and may even occur before the onset of muscular contractions as anticipatory response. Pulmonary ventilation increases during exercise in direct proportion to the metabolic needs of exercising muscle.

Explain the Valsalva maneuver.

The Valsalva maneuver is a potentially dangerous respiratory procedure that frequently accompanies certain types of exercise, in particular the lifting of heavy objects. This occurs when the individual closes the glottis, increases the intra-abdominal pressure, and increases the inthrathoracic pressure. If held for an extended period of time, this maneuver can greatly reduce the volume of blood returning to the heart, decreasing cardiac output and lowering arterial blood pressure.

What role does the respiratory system play in acid-base balance?

The respiratory system plays a crucial role in rapid adjustment of the body’s acid-base status during and immediately after exercise. It does this by controlling the amount of carbon dioxide in the blood because an increase in free H+ in the blood stimulates the respiratory center to increase ventilation. This facilitates the binding of H+ to bicarbonate and the removal of carbon dioxide.

What is the normal resting pH for arterial blood? For muscle? How are these values changed as a result of exhaustive sprint exercise?

The normal resting pH for arterial blood is 7.4 and the normal resting pH for muscle is 7.1. As a result of an exhaustive sprint exercise muscle pH drops to about 6.63 and arterial blood pH drops to about 6.9.

What are the primary buffers in the blood?

The primary buffers in the blood are bicarbonate, hemoglobin, proteins, and phosphates.

Define and differentiate the terms strength, power, and muscular endurance.

Strength is defined as the maximal force that a muscle or muscle group can generate. Power is defined as the rate at which work is performed and thus is the product of force and velocity. Unlike strength, power has a speed component. Muscular endurance is the capacity to perform repeated muscle contractions, or to sustain a contraction over time.

Define aerobic and anaerobic power.

Aerobic power is the rate of energy release by cellular metabolic processes that depend on the continued availability of oxygen. In contrast, anaerobic power is the rate of energy release by cellular metabolic processes that function without the involvement of oxygen.

Describe and provide examples for the principles of individuality, specificity, reversibility, progressive overload, and variation.

Individuality is the idea that heredity plays a major role in determining the body’s response to a single bout of exercise, as well as the chronic changes that result from a training program. An example of this is when some people show great improvement after participating in a given program whereas others experience little or no change after following the same program. Specificity means that exercise adaptations are specific to the mode, intensity, and duration of training. This means that the training program must stress the physiological systems that are critical for optimal performance in a given sport in order to achieve specific training adaptations and goals. For example, to improve muscular power a shot putter would not emphasize distance running or slow, low-intensity resistance training, instead they would develop explosive movements. The principle of reversibility explains that if training is decreased or stopped, the physiological adaptations that caused those improvements in performance will be reversed. For example if a weight lifter suddenly stops weight training they will gradually lose the ability to lift as heavy of weights. According to the principle of progressive overload, systematically increasing the demands on the body is necessary for continued improvement. In a resistance training program, in order to gain strength, the muscles must be overloaded, meaning the weight must be challenging and provide a greater stimulus than what the individual adapted to during previous sessions. For example, a woman who can perform only 10 repetitions of a bench press using 66lbs should be able to increase to 14 or 15 reps with the same weight over a week or two. The principle of variation is the systematic process of changing one or more variables in the training program over time to allow for the training stimulus to remain challenging and effective. For example someone may manipulate training intensity and volume of training over time intervals to achieve peak levels of fitness for competition.

What factors need to be considered when one is designing a resistance training program?

When designing a resistance training program factors that need to be considered are the exercises that will be performed, the order in which they will be performed, the number of sets for each exercise, the rest periods between sets and between exercises, and the amount of resistance, the number of repetitions, and the velocity of movement to be used.

What would be an appropriate range of resistance and repetitions when one is designing a resistance training program targeted to develop strength? Muscular endurance? Hypertrophy?

For a training program to develop strength an appropriate range of resistance for an intermediate lifter would be 70%-80% of 1 RM, with multiple sets of 6-12 reps. For a training program to develop muscular endurance an appropriate range of resistance for an intermediate lifter would be light, with 1-3 sets of 10-15 reps. For a training program to develop muscle hypertrophy an appropriate range of resistance for an intermediate lifter would be 70%-85% of 1 RM, with 1-3 sets of 6-12 reps.

High-intensity interval training (HIIT) has been shown to cause beneficial adaptations leading to improved performance. Describe those physiological adaptations.

Physiological adaptations that are caused by high-intensity interval training are a significant increase in VO2max, maximal cardiac output, and stroke volume. HIIT also improves glucose control and insulin sensitivity, along with vascular endothelial function.

What is a reasonable expectation for percentage strength gains following a 6-month resistance training program? How do these percentage gains differ by age, sex, and previous resistance training experience?

Following a 6-month resistance training program it is reasonable to expect 25% to 100% improvement, sometimes even more. If a subject has no previous training experience, they experience the largest improvements, with most of their early gains in strength being the result of learning how to more effectively produce force, and this learning effect can account for as much as 50% of the early strength gains. Young adults generally gain strength faster and to a greater extent than older adults. In terms of sex, both men and women experience similar percentage increases in strength, but men tend to gain more absolute strength.

What is the suggested minimal intensity for resistance training that will lead to muscle hypertrophy when the exercises are performed to volitional fatigue?

The suggested minimal intensity for resistance training that will lead to muscle hypertrophy when the exercises are performed to volitional failure is 30% of 1RM.

Differentiate between transient and chronic muscle hypertrophy.

Transient muscle hypertrophy is the increased muscle size that develops during and immediately following a single exercise bout. Chronic muscle hypertrophy is the increase in muscle size that occurs with long term resistance training.

How has muscle fiber hypertrophy been used to explain increasing muscle size with resistance training?

Muscle fiber hypertrophy is the actual structural changes in the muscle that can result from an increase in the size of existing individual muscle fibers. Muscle fiber hypertrophy is caused by increased numbers of myofibrils and actin and myosin filaments, which provide more cross bridges for force production during maximal contraction. This increased size of individual muscle fibers increases the overall size of the muscle.

What is fiber hyperplasia? How might it occur?

Fiber hyperplasia is an increase in the total number of muscle fibers within a muscle, caused by resistance training, increasing overall muscle size. Research on animals has shown that with intense strength training, selected muscle fibers appeared to actually split in half, and each half then increased to the size of the parent fiber. It is postulated that individual muscle fibers have the capacity to divide and split into two daughter cells, each of which can then develop into a functional muscle fiber.

What is the physiological basis for hypertrophy?

The physiological basis for hypertrophy is that resistance training puts stress on muscle fibers, which causes microscopic damage that stimulates the muscle to repair and adapt by increasing the size of existing muscle fibers through greater protein synthesis.

What is the physiological response to muscle immobilization?

When a trained muscle suddenly becomes inactive through immobilization the rate of protein synthesis starts to decrease in the first 6 hours. This decrease likely initiates muscular atrophy and the size of the muscle tissue decreases. Immobilization appears to affect both type I and type II fibers, with researchers observing disintegrated myofibrils, streaming Z-disks, and mitochondrial damage. Studies have shown the effect to be greater in type I fibers, including a decrease in the percentage of type I fibers, which increases the relative percentage of type II fibers.

To support protein synthesis during resistance training, what type of protein should be ingested and how much?

To support protein synthesis during resistance training the best forms of protein for muscle hypertrophy are easily and rapidly digested and rich in essential amino acids, especially leucine. Whey protein found in milk is one example of a source that meets both goals. After resistance training, athletes should consume a small amount of high-quality protein along with adequate carbohydrate to stimulate muscle proteins and replenish muscle glycogen stores after exercise.

Is there an optimal timing for protein ingestion when an individual is trying to optimize the hypertrophic response to successive exercise sessions?

The optimal timing for protein ingestion lasts from just before the start of resistance exercise to several hours postexercise. Therefore providing protein before or during exercise can enhance muscle protein synthesis during exercise and is a good strategy for prolonged or repeated workouts. Also, ingesting repeated small doses of protein during recovery from resistance training may be more effective in increasing muscle hypertrophy than eating just one large meal.

What is the role of mTOR in protein synthesis?

The rate of protein synthesis within the myofibrils is controlled primarily by mTOR. It integrates the input from upstream pathways, including insulin and growth factors and amino acids, and controls transcription of mRNA. mTOR also senses cellular nutrient and oxygen levels, so it is also activated by the proper timing of protein intake.

How do the basic guidelines for prescribing resistance training exercise for children differ from those for adults?

Resistance training programs for children are prescribed in a very similar way as for adults, however there is an emphasis on teaching proper lifting technique.

Differentiate between muscular endurance and cardiovascular endurance.

Muscular endurance is the ability of a single muscle or muscle group to maintain high-intensity, repetitive, or static contractions. Cardiovascular endurance is the ability to sustain prolonged dynamic, whole body exercise using large muscle groups.

What is the maximal oxygen update (VO2max)? How is it defined physiologically, and what determines its limits?

VO2max is regarded as the best objective laboratory measure of cardiorespiratory endurance and is defined as the highest rate of oxygen consumption attainable during maximal or exhaustive exercise. VO2max is determined by maximal cardiac output and the maximal (a-v̄)O2 difference. Two contrasting theories have been proposed for what factors limit VO2max. The first theory explains that endurance performance was limited by the lack of sufficient concentrations of oxidative enzymes in the mitochondria. The second theory explains that central and peripheral cardiovascular factors limit endurance capacity. Evidence strongly supports the second theory, with studies indicating that oxygen transport to the working muscles, not the available mitochondria and oxidative enzymes, limits V̇O2max.

Of what importance is VO2max to endurance performance?

VO2max increases substantially following endurance training and represents the maximum rate at which the body can take in, transport, and use oxygen during intense exercise. Therefore the higher the VO2max, the better one’s endurance performance.