Rate Limiting Factor
BPK 310 – Assignment 1
UNIT 1
Question 1 (5 marks): Discuss the rate-limiting factor. Why is it important to consider when studying exercise physiology and training? Provide one example to clarify your understanding.
The rate-limiting factor is the “step” that limits performances (the “slow step”). If we know the rate-limiting step in a certain physiological pathway or training situation, we can manipulate the factors of this step to change and increase the rate of the pathway. This will improve overall training and performance. For example, in an assembly line, there are different tasks required. The most difficult and time-consuming task is the rate-limiting factor. If there was a way to increase the efficiency of this particular task, it …show more content…
Describe these three concepts in more detail, and explain how each of them illustrates that ventilation does not limit V̇O2 max at sea level.
Alveolar partial pressure (PAO2) refers to the amount of oxygen in the alveoli of the lungs. When a person begins exercising, the PAO2 will be relatively constant during lower levels of pulmonary ventilation, and then begins to rise as pulmonary ventilation increases heavily and progresses into hyperventilation. The increase in PAO2 during maximal exercise tells us that there is a greater amount of oxygen left in the alveoli in the lungs when compared the person at rest. Ventilation is not dependent on PAO2, since the PAO2 levels remain relatively constant while ventilation begins and only increases slowly when ventilation becomes harder.
We are also able to increase the amount that we are breathing (ventilation perfusion) more than the increase in oxygen consumption or cardiac output (Q). This can be expressed by the ventilation perfusion ratio, which is VE/Q. As illustrated by the example in the following figure, the ratio increases about 7 times from rest to maximal …show more content…
Elite athletes generally will have a lower resting HR than individuals who do not exercise periodically. With exercise, sympathetic stimulation will increase HR and different feedback systems will modulate the response of the cardiovascular system, such as stretching of the blood vessel walls (mechanical stimulation) and metabolite changes (chemical stimulation). HR will reach a maximum during maximal exercise and it can be estimated by using this equation: 220 bpm – age of individual, with an error of +/- 12 bpm. Maximal HR is generally within the range of 180-200 bpm (Brooks et al., 2005, p. 345).
Stroke volume (SV) is approximately 70 ml/min at rest (Brooks et al., 2005, p. 342). SV will increase linearly with exercise and will plateau before it reaches the maximum (only 25-50% of maximum). Training will also cause an increase in SV. However, there is no change in SV when the subject is in a supine position, since the heart does not need to pump as much and work against gravity when the body is laying
UNIT 1
Question 1 (5 marks): Discuss the rate-limiting factor. Why is it important to consider when studying exercise physiology and training? Provide one example to clarify your understanding.
The rate-limiting factor is the “step” that limits performances (the “slow step”). If we know the rate-limiting step in a certain physiological pathway or training situation, we can manipulate the factors of this step to change and increase the rate of the pathway. This will improve overall training and performance. For example, in an assembly line, there are different tasks required. The most difficult and time-consuming task is the rate-limiting factor. If there was a way to increase the efficiency of this particular task, it …show more content…
Describe these three concepts in more detail, and explain how each of them illustrates that ventilation does not limit V̇O2 max at sea level.
Alveolar partial pressure (PAO2) refers to the amount of oxygen in the alveoli of the lungs. When a person begins exercising, the PAO2 will be relatively constant during lower levels of pulmonary ventilation, and then begins to rise as pulmonary ventilation increases heavily and progresses into hyperventilation. The increase in PAO2 during maximal exercise tells us that there is a greater amount of oxygen left in the alveoli in the lungs when compared the person at rest. Ventilation is not dependent on PAO2, since the PAO2 levels remain relatively constant while ventilation begins and only increases slowly when ventilation becomes harder.
We are also able to increase the amount that we are breathing (ventilation perfusion) more than the increase in oxygen consumption or cardiac output (Q). This can be expressed by the ventilation perfusion ratio, which is VE/Q. As illustrated by the example in the following figure, the ratio increases about 7 times from rest to maximal …show more content…
Elite athletes generally will have a lower resting HR than individuals who do not exercise periodically. With exercise, sympathetic stimulation will increase HR and different feedback systems will modulate the response of the cardiovascular system, such as stretching of the blood vessel walls (mechanical stimulation) and metabolite changes (chemical stimulation). HR will reach a maximum during maximal exercise and it can be estimated by using this equation: 220 bpm – age of individual, with an error of +/- 12 bpm. Maximal HR is generally within the range of 180-200 bpm (Brooks et al., 2005, p. 345).
Stroke volume (SV) is approximately 70 ml/min at rest (Brooks et al., 2005, p. 342). SV will increase linearly with exercise and will plateau before it reaches the maximum (only 25-50% of maximum). Training will also cause an increase in SV. However, there is no change in SV when the subject is in a supine position, since the heart does not need to pump as much and work against gravity when the body is laying