Comprehensive Exercise Physiology: Muscle, Cardiovascular, and Metabolic Responses

What promotes catabolic reactions?

Low cell energy

Where does oxidative phosphorylation occur?

Mitochondria

What drives the reduction of pyruvate to lactate?

Mass action effect, Low redox potential, PFK stimulation

What is the product of ATP hydrolysis?

ADP + Pi + H(ion) + heat + energy

What is the process of adding a phosphate group called?

Phosphorylation

How much ATP does a 16-carbon fatty acid yield from the Krebs cycle?

80 ATP

What is responsible for lowering the activation energy of a chemical reaction?

Enzyme activity

Why is CHO relied on more than fatty acids as exercise intensity increases?

CHO yield more ATP per oxygen molecule

What is the primary ATP source for an 800 meter running event?

Anerobic glycolytic system

Why is muscle glycogen preferred during exercise?

It yields more ATP than blood glucose and fatty acids

What is a function of lactate in the body?

Fuel source, acts as a buffer, converted back to glucose via Cori cycle

What is an example of an energy substrate?

Palmitic acid

What explains Carl's increase in muscle size after resistance training?

Hypertrophy increasing myofibril size and myonuclei formation

What is the functional unit of skeletal muscle?

Sarcomere

What are the characteristics of type 2a (IIa) motor units?

Fast contraction velocity, high glycolytic and oxidative capacity

What happens to the sarcomere during contraction?

Actin slides past myosin

What is the role of the Na+/K+ ATPase pump?

Maintain resting membrane potential

What occurs during hyperpolarization?

More negative resting membrane potential

What is the role of the basal ganglia?

Aids in initiating repetitive movements

What ion is most important for repolarization?

K+ (potassium)

What is the effect of sympathetic nervous system stimulation on metabolism?

Stimulates lipolysis

What type of contraction occurs in quadriceps while descending stairs?

Eccentric contraction

What happens to muscle fiber type with training?

Type 2x transitions to type 2a

What is the effect of muscle glycogen depletion on motor unit recruitment?

Induces motor unit fatigue, increasing energy cost of movement

What is true about leg muscles of sprinters vs. marathon runners?

Force generated by similar-sized muscle fibers is similar

What is the recruitment strategy during prolonged isometric holds?

Asynchronous motor unit recruitment

What is the relationship between muscle strength and cross-sectional area?

Positively correlated

What is the Compromise of her hypothalamus?

According to Heneman's size principle, which motor units are recruited first?

Small motor units

Which proprioceptor is NOT part of a motor reflex?

Chemoreceptor

What is generated if membrane potential changes from -70 mV to -55 mV?

Only an excitatory postsynaptic potential (EPSP)

What is the first event following exercise-induced muscle damage?

Local inflammatory response (IL-6) and neutrophil infiltration due to chemotaxis

What is a correct exercise intensity prescription for Francine to oxidize 50% carbohydrates?

2.5 mph

What occurs at running speeds above lactate threshold?

VO2 drift

What is the primary concern of conducting a graded exercise test with 1 minute stages?

It is unknown whether steady state will be achieved

Which equation yields the most accurate estimation of energy expenditure during walking?

LCDA

Why is Lactate Threshold important in endurance events?

Athletes cannot sustain exercise intensity above the pace at which blood lactate accumulates for longer than 30-35 minutes

What causes acute muscle soreness?

Accumulation of fluid and H+ that sensitize nociceptors

Which is NOT a cause of strength loss with DOMS?

Accumulation of lactic acid in muscle tissue

DOMS is ____________ the development of fiber hypertrophy.

Not essential for

What is a risk factor for exercise-associated muscle cramping?

Exercise unmatched to fitness

What metabolic pathways bridge the ATP gap during oxygen deficit?

PCr (anaerobic) and Glycolysis (anaerobic)

What occurs during uphill walking?

Localized muscle glycogen depletion will occur, primarily in the quadriceps and gastrocnemius

What can be inferred from Ronda's graded exercise test results?

A VO2max was achieved

What is a typical RER value for a fasted individual at rest?

0.75

At what intensities do muscle fatigue and inefficiency occur during whole body exercise?

Above the lactate threshold

What can motivational self-talk decrease and increase during exercise?

Decrease: RPE, Increase: Endurance

When does the lactate threshold typically occur in untrained individuals?

50% VO2max

Why does aerobic performance continue to improve with training after VO2max plateaus?

Lactate Threshold continues to improve with training

What is a hallmark of acute muscle soreness?

Increased concentrations of muscle enzymes circulating in the bloodstream

What happens when movement economy is improved?

Less VO2 is consumed for any given submaximal speed

What is the most likely source of reduced force production in Bonnie's study?

Central Nervous System Fatigue

What is true about the inflammatory response post muscle damage?

It is necessary for satellite cell differentiation and proliferation

When is oxygen deficit incurred?

O2 demand > O2 consumption in early exercise

During prolonged distance running, where does muscle fatigue occur most often?

Gastrocnemius

What occurs when RER < 0.7?

Diet-induced gluconeogenesis is occurring

What cells are attached to the injury site first after z-line disruption?

Neutrophils

What happens when liver and glycogen stores run low in an endurance race?

FFA metabolism is slower than glycogen metabolism

What occurs in the cell if muscle pH falls to 6.4?

Glycogen breakdown becomes severely diminished

Steroid hormones are derived from what, making them what type of soluble?

Cholesterol, lipid soluble

What is slower, FFA metabolism or glycogen metabolism?

FFA metabolism is slower than glycogen metabolism.

What occurs in the cell when muscle pH falls to 6.4?

Glycogen breakdown becomes severely diminished.

Steroid hormones are derived from what and how soluble are they?

Cholesterol; Lipid soluble.

What happens as a result of altitude training over 2,500 meters?

Hypoxia induces EPO release from the kidneys, increasing hemoglobin concentration.

How is hormone secretion characterized?

Pulsatile.

What does the renin angiotensin aldosterone system help restore?

Blood volumes and blood pressure.

At what exercise intensity do norepinephrine concentrations increase?

Moderate exercise intensity.

At what exercise intensity do epinephrine concentrations increase?

High exercise intensity.

What stimulates glucose mobilization?

Glucagon.

What stimulates glucose uptake by cells?

Insulin.

Why do plasma glucose concentrations decline after prolonged exercise?

Liver glycogen stores are depleted.

What is the primary means by which hormones maintain homeostasis?

Negative Feedback mechanisms.

Which hormones typically act in opposition?

Insulin and Glucagon.

In which exercise domain is VO2max achieved?

Moderate, Heavy, Severe, Extreme.

What is the primary glucocorticoid that mobilizes FFAs?

Cortisol.

What happens to glucagon and insulin concentrations during exercise?

Glucagon increases; Insulin decreases.

Which hormone is NOT secreted by the anterior pituitary gland?

Renin.

What senses blood osmolality?

Hypothalamus.

What is the normal body fluid osmolality?

Approximately 300 mOsm/kg.

What happens when PO2 is approximately 20 mmHg?

Loading O2.

What occurs if phase 3 of the ventilatory response to exercise is blunted?

Steady state would be less 'steady'.

What is the pressure gradient in the pulmonary circulation?

Approximately 10 mmHg.

What occurs when chemoreceptors stimulate an increase in breathing rate?

Excess CO2 needs to be removed.

What moves from plasma into red blood cells to prevent ionic imbalance?

Chloride (Cl-).

What type of test is required to determine ventilatory threshold?

Graded exercise test.

What is the effect of endurance training on respiratory muscles?

Improves oxidative capacity.

What does the Respiratory Compensation Point (RCP) indicate?

Uncoupling of regulation of ventilation by PCO2 and acidosis.

Will Chris P. Bacon's performance be impaired at Mt. Washington?

No, > 97.5% hemoglobin saturation.

What is significant about the O2-hemoglobin and O2-myoglobin dissociation curves?

Myoglobin's curve is steeper, indicating off-loading O2 at lower PO2.

What limits maximal endurance performance?

Ventilation is not a limiting factor except in elite athletes or at altitude.

During moderate exercise in heat, which vascular beds receive the most blood flow?

Muscle and skin.

What does the Valsalva Maneuver do?

Reduces preload, cardiac output, and arterial blood pressure.

How can Cardiac Drift occur quickly?

Hot environmental conditions or dehydration.

What effect does increased blood pressure during exercise have on plasma volume?

It decreases plasma volume.

Which mechanism does NOT increase stroke volume during exercise?

Catecholamines stimulation of the SA node.

What percentage of cardiac output do respiratory muscles receive during maximal exercise?

15% of cardiac output.

What leads to an increase in stroke volume due to norepinephrine?

Increased contractility and preload.

What explains the cardiorespiratory responses to an acute increase in exercise intensity?

Tidal volume and stroke volume increase more than heart rate and respiratory rate.

Which does NOT contribute to ventilatory regulation during exercise?

Baroreceptors in carotid sinus.

What leads to vasodilation during exercise?

Accumulation of metabolic by-products (H+, CO2, Heat).