Exercise Physiology Practice Questions

Q: What happens to the pressure in the calf compartment during the heel touch phase of walking?

Increases compared to resting pressure. ***Increases compared to resting pressure*** - During **heel strike (initial contact)**, the calf muscles (**gastrocnemius and soleus**) contract eccentrically to control ankle dorsiflexion and decelerate the foot - Simultaneous **weight bearing** and **muscle contraction** within the confined fascial compartment lead to increased intramuscular pressure - This is a well-documented phenomenon in gait biomechanics and exercise physiology *Decreases compared to resting pressure* - Incorrect: Muscle activation and weight bearing during initial contact inherently increase compartment pressure - Pressure decrease occurs during swing phase when the limb is unloaded and muscles are relaxed *First increases and then decreases* - While pressure varies throughout the complete gait cycle, the **heel touch phase specifically** is characterized by an initial pressure increase - The brief duration of heel strike does not typically show a biphasic pressure pattern within this single phase *Remains the same as resting pressure* - Incorrect: Active weight bearing and eccentric muscle contraction during heel strike necessarily elevate intramuscular pressure above resting levels - Resting pressure only occurs when the limb is unloaded and muscles are inactive

Q: Which of the following is a characteristic feature of athletic heart syndrome?

Increased left ventricular wall thickness. ***Increased left ventricular wall thickness*** - **Physiological cardiac remodeling** in athletes often leads to an increase in **left ventricular muscle mass** and wall thickness in response to chronic exercise. - This adaptation allows the heart to pump more blood per beat, improving **cardiac efficiency** and **stroke volume**. *Bradycardia* - While **bradycardia** (a slower heart rate) is common in trained athletes, it is a consequence of increased **vagal tone** and enhanced stroke volume, not a defining characteristic of the morphological changes of athletic heart syndrome itself. - The syndrome primarily refers to the structural adaptations of the heart, like ventricular hypertrophy and chamber dilation. *Normal QT interval* - A **normal QT interval** is generally expected in athletic heart syndrome, whereas a **prolonged QT interval** is a sign of underlying pathology (e.g., long QT syndrome) and would raise concern for cardiac arrhythmias. - This is a feature indicating the benign nature of athletic heart and helps differentiate it from pathological conditions. *Increased U-waves* - **Prominent U-waves** on an electrocardiogram are more commonly associated with conditions like **hypokalemia** or certain antiarrhythmic drugs, not typically with athletic heart syndrome. - While some ECG changes can occur, increased U-waves are not a characteristic finding specifically linked to this physiological adaptation.

Q: During moderately intense isotonic exercise, all of the following increase except:

Total Peripheral resistance. ***Total Peripheral resistance*** - During isotonic exercise, **vasodilation** in working muscles leads to a decrease in **total peripheral resistance** to facilitate increased blood flow and oxygen delivery. - While some vascular beds constrict, the overwhelming effect of vasodilation in active muscles causes a net decrease in overall resistance. *Mean arterial pressure* - **Mean arterial pressure** typically increases during isotonic exercise due to a significant rise in **cardiac output** that outweighs the decrease in total peripheral resistance. - This increase helps maintain adequate perfusion pressure to active muscles and other vital organs. *Heart rate* - **Heart rate** increases proportionally with exercise intensity during isotonic exercise to meet the increased metabolic demands of the working muscles. - This is a primary mechanism to boost **cardiac output** and oxygen transport. *Respiratory rate* - **Respiratory rate** increases during isotonic exercise to enhance **gas exchange**, removing CO2 and taking in more O2 to support the heightened metabolic activity. - This response is driven by the body's need to maintain **acid-base balance** and provide sufficient oxygen to tissues.

Q: During a maximal exercise test, which of the following best describes the likely changes in his muscle oxygen extraction and arteriovenous oxygen difference (a-vO2 diff)?

Increased muscle oxygen extraction and increased a-vO2 diff. ***Increased muscle oxygen extraction and increased a-vO2 diff*** - During **maximal exercise**, skeletal muscles have a significantly **higher metabolic demand** for oxygen to produce ATP. - This increased demand leads to greater **oxygen extraction** from the blood by the muscles, resulting in a larger difference between the arterial and venous oxygen content (**a-vO2 diff**). *Decreased muscle oxygen extraction and decreased a-vO2 diff* - This scenario would imply a **reduced oxygen utilization** by the muscles and a smaller difference in oxygen content, which is contrary to the body's physiological response during intense exercise. - Such a decrease would lead to rapid **fatigue** and an inability to sustain high-intensity activity due to insufficient energy production. *Increased muscle oxygen extraction and decreased a-vO2 diff* - An increase in muscle oxygen extraction is correct, but a **decreased a-vO2 diff** is contradictory. If more oxygen is extracted, the venous oxygen content would be lower, thereby increasing the a-vO2 diff. - A decreased a-vO2 diff alongside increased extraction would suggest an unphysiologic process or an error in understanding the relationship between these two variables. *Decreased muscle oxygen extraction and increased a-vO2 diff* - This option presents a contradiction: a **decreased muscle oxygen extraction** would logically lead to a *smaller* a-vO2 diff, as less oxygen is being removed from the blood. - An increased a-vO2 diff would only occur with *increased* oxygen extraction by the tissues.

Question 1

During moderate exercise, the respiratory rate increases in response to which of the following?

Accepted Answer

Increased PCO2 in arterial blood

Answer

Proprioceptive feedback from muscle spindles

Answer

Decreased PO2 in arterial blood

Answer

Stimulation of J-receptors

Question 2

What happens to the pressure in the calf compartment during the heel touch phase of walking?

Accepted Answer

Increases compared to resting pressure

Answer

Decreases compared to resting pressure

Answer

First increases and then decreases

Answer

Remains the same as resting pressure

Question 3

Which of the following is a characteristic feature of athletic heart syndrome?

Accepted Answer

Increased left ventricular wall thickness

Answer

Bradycardia

Answer

Normal QT interval

Answer

Increased U-waves

Question 4

During moderately intense isotonic exercise, all of the following increase except:

Accepted Answer

Total Peripheral resistance

Answer

Respiratory rate

Answer

Heart rate

Answer

Mean arterial pressure

Question 5

During a maximal exercise test, which of the following best describes the likely changes in his muscle oxygen extraction and arteriovenous oxygen difference (a-vO2 diff)?

Accepted Answer

Increased muscle oxygen extraction and increased a-vO2 diff

Answer

Decreased muscle oxygen extraction and decreased a-vO2 diff

Answer

Increased muscle oxygen extraction and decreased a-vO2 diff

Answer

Decreased muscle oxygen extraction and increased a-vO2 diff

Exercise Physiology — MCQs

Exercise Physiology — MCQs

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