Ch 11 Quiz
What happens to heart rate recovery following aerobic training?
heart rate recovery speeds up, i.e. a person's post-exercise heart rate returns to resting heart rate more quickly [Heart rate recovery is improved following aerobic training, due primarily to greater stroke volume capacity.]
What effect does increased capillarization in muscle fibers have on (a-v)O2 difference?
Higher arterial O2 content, increased (a-v)O2 difference [increased capillarization in the muscle fibers will not affect arterial O2 content, but it will increase the amount of O2 that can be extracted by muscle fibers, which leads to an icrease in (a-v)O2 difference.]
How does blood volume respond to aerobic training?
Increased plasma volume, increased red blood cell volume [following aerobic training, both plasma volume and red blood cells increase. Remember that the plasma volume will often increase to a greater extent than red blood cells, which results in a net slight decrease in hematocrit (and viscosity, which is beneficial).]
After months of progressive aerobic training, you notice that your resting heart rate has decreased. What else is going on?
Increased resting stroke volume, unchanged (or slightly increased) resting cardiac output [In response to aerobic training, resting heart rate goes down, stroke volume goes up, and cardiac output stays roughly the same (or can increase slightly, related to increased blood volume).]
What effect does an increase in the concentration of oxidative enzymes like succinate dehydrogenase (SDH) or citrate synthase have on ATP production during prolonged aerobic activity?
]greater reliance on lipids [The question stem is describing glycogen sparing, whereby the increase in oxidative enzymes -- along with the increase in the number, size, and activity level of mitochondria in general -- allows more ATP to be produced from lipids. Thus, glycogen is broken down more slowly ("spared").]
Which type of training will lead to the biggest increases in the concentration of phosphocreatine (PCr) and glycolytic enzymes like phosphofructokinase (PFK)?
bouts of 30 seconds to fatigue [Phosphocreatine and glycolytic enzymes will be stimulated most by high-intensity anaerobic activity that fully exhausts the stored ATP-PCr reserves and stresses the glycolytic ATP production system. The longer intervals and long, sustained activity will stress the oxidative ATP production systems.]
What effect does decreased systemic vascular resistance (a.k.a. afterload) have on end-systolic volume and stroke volume?
decreased end-systolic volume, increased stroke volume [A higher vascular resistance would reduce the amount of blood that can be ejected from the ventricles, therefore end-systolic volume (the blood "left over" in the ventricles) is higher. This question describes the opposite: decreased vascular resistance -- as is common after aerobic training -- would lead to an increase in the amount of blood that can be ejected from ventricles, therefore a lower ESV and a higher stroke volume.]
Aerobic training leads to an increased lactate threshold, driven by which factors?
decreased lactate production and increased lactate clearance [the onset of lactate accumulation (lactate threshold) is delayed after training, and occurs at a higher exercise intensity. This increased lactate threshold is due to both a decrease in lactate production and an increased ability to remove lactate and shuttle it to the liver or other body tissues]
Aerobic training leads to what changes at the same submaximal intensity (such as biking at the same power output)?
higher stroke volume, lower heart rate [following aerobic training, the same submaximal exercise intensity requires the same VO2 and the same cardiac output (with possible minor reductions in VO2 and cardiac output if movement economy improves). Having the same cardiac output means that the product of stroke volume and heart rate stays the same. Following aerobic training, stroke volume increases and heart rate decreases at submaximal exercise intensities.]
What is the primary effect of aerobic training on muscle fibers?
increased area of Type I fibers [The major effect of aerobic training is fiber hypertrophy (size) of Type I fibers. There is also some conversion of Type II-x to Type II-a fibers and potentially a small amount of Type I fiber hyperplasia after a long period of intense aerobic training.]
Which of the following will NOT have a positive effect on endurance performance?
increased vascular resistance [This question is a nice summary of main factors affecting endurance performance, and also some of the main benefits of aerobic training. All of the increases would improve endurance performance, except increased vascular resistance. Decreased vascular resistance allows a higher maximal stroke volume, which would benefit performance]
If a person improves their movement economy, then the same exercise intensity (e.g. running speed) will require ____ VO2.
lower
What happens to maximal cardiac output following aerobic training?
maximal cardiac output goes up, driven by increased maximal stroke volume [Increased cardiac output is the primary determinant of increased aerobic capacity (VO2max) following aerobic training, and the increase in max cardiac output is driven by increased max stroke volume with little to no effect on max heart rate.]
Which of the following is NOT an effect of anaerobic training?
type I fiber hyperplasia [Increased Type II fiber cross-sectional area (both Type II-a and Type II-x), increased glycolytic enzyme activity, and increased ATP/PCr capacity all result from anaerobic training. While there may be a small increase in Type I fiber cross-sectional area, there will not be Type I fiber hyperplasia following anaerobic training. (And as an aside, any hyperplasia of Type II-a or Type II-x fibers will be minor and in response to long-term, high-level anaerobic training, similar to what we've discussed previously for resistance training.)]