Lesson 6 - Physiology of Training

Question 1

The sinoatrial node (SA node), which is sometimes called the pacemaker of the heart, is located
in which chamber of the heart?

Answer 1

Right atrium

Why?

The SA node is located on the posterior wall of the right atrium, while the atrioventricular node
(AV node) is located on the floor of that same chamber.

ACE’s Essentials of Exercise Science for Fitness Professionals, p. 214

Question 2

Which of the following is NOT a method the body uses to preserve blood volume during steady-state exercise?

Answer 2

Increasing stroke volume

Why?

The following changes take place to preserve blood volume:
A progressive increase in heart rate at steady-state exercise to maintain cardiac output and offset the small
decrease in stroke volume associated with the fluid loss
A compensation in blood pressure via further vasoconstriction in the non-exercising regions to maintain
peripheral resistance and blood pressure
A release of hormones—antidiuretic hormone, or vasopressin, and aldosterone—to help reduce water and
sodium losses from the body

ACE’s Essentials of Exercise Science for Fitness Professionals, p. 216

Question 3

Minute ventilation decreases after an exerciser crosses the second ventilatory threshold (VT2).

Answer 3

False

Why?

During submaximal exercise, ventilation increases linearly with oxygen consumption and carbon
dioxide production. This occurs primarily through an increase in tidal volume (i.e., the volume of
air inhaled and exhaled per breath). At higher or near-maximal intensities (above VT2), the
frequency of breathing becomes more pronounced and minute ventilation rises
disproportionately to the increases in oxygen consumption. Tidal volume decreases as breathing
rate increases.

ACE’s Essentials of Exercise Science for Fitness Professionals, p. 217-218

Question 4

What hormone dilates the respiratory passages and reduces digestive activity and bladder
emptying during physical activity?

Answer 4

Epinephrine

Why?

In addition to its effects on the cardiovascular and metabolic systems, epinephrine dilates the
respiratory passages to aid in moving air into and out of the lungs, and reduces digestive
activity and bladder emptying during exercise.

ACE’s Essentials of Exercise Science for Fitness Professionals, p. 218

Question 5

Which slow-acting hormone stimulates the mobilization of free fatty acids from adipose tissue,
mobilizes glucose synthesis in the liver, and decreases the rate of glucose utilization in the cells?

Answer 5

Cortisol

Why?

Cortisol is a glucocorticoid released from the adrenal cortex that stimulates free fatty acid (FFA)
mobilization from adipose tissue, mobilizes glucose synthesis in the liver (i.e., gluconeogenesis),
and decreases the rate of glucose utilization by the cells. Its effect is slow, however, allowing
other fast-acting hormones such as epinephrine and glucagon to primarily deal with glucose and
FFA mobilization.

ACE’s Essentials of Exercise Science for Fitness Professionals, p. 219

Question 6

Which mechanism of thermoregulation is the major contributor during exercise?

Answer 6

Evaporation

Why?
Though evaporation accounts for only 20% of thermoregulation while at rest, it accounts for
approximately 80% of thermoregulation during exercise.

ACE’s Essentials of Exercise Science for Fitness Professionals, p. 225

Question 7

During what phase of the general adaptation syndrome will a client see progressive increases in
muscle size and strength?

Answer 7

Adaptation phase

Why?

The adaptation phase, or resistance phase, generally begins around weeks four through six and
represents major muscular adaptations (biochemical, mechanical, and structural). This phase is
characterized by progressive increases in muscle size and strength

ACE’s Essentials of Exercise Science for Fitness Professionals, p. 232

Question 8

An individual is using a resistance band to perform very short-duration (less than 2 seconds per
stretch) hamstring stretches in sets of eight repetitions. What flexibility-training technique is
this person using?

Answer 8

Active isolated stretching

Why?

Active isolated stretching follows a design similar to a traditional strength-training workout.
Instead of holding stretches for 15 to 30 seconds at a point of resistance (i.e., mild discomfort),
stretches are never held for more than two seconds. The stretch is then released, the body
segment returned to the starting position, and the stretch is repeated for several repetitions.

ACE’s Essentials of Exercise Science for Fitness Professionals, p. 243