Page 1 of 15Exercise Physiology Exam 3Aerobic capacity 1. Explain the concept of VO2 max, include what it measures, how you determine if a subject has reached it, and explain clearly how this information can be used.- VO2 max is a measure of the maximum volume of oxygen that our working muscles can extract. This value is considered the benchmark of cardiorespiratory fitness, in both the medical world and in the athletic world. It can be defined in two ways: Relative or absolute.- Relative is ml/kg/min and absolute is in L/min. The difference is that relative takes into account an individual’s body weight, so it is relative to them. So you can’t necessarily compare a 200lb fit runner to a 120 lb fit runner withrelative Vo2. - This value is obtained in a progressive maximal test. As the test runs, the difficulty (either speed or incline) is increased, until the participant voluntarily stops or runs to exhaustion. Once they have reached the point where there oxygen intake ceases to increase (they are attached to a metabolic cart with tubes) and they can still exercise,then they have reached their VO2max (this rarely occurs when non-elite athletes test). Other indications that the max is reached is if RER is greater than 1.10, age predicated HR is obtained within 10 BPM, and blood lactate is measured at 8-10 mmol. This lactate level signifies extreme levels in the blood.- Tests can either be continues, with no rest increments, or discontinues with rest. They yield similar values. A maximal treadmill test is the best predictor, as the most muscle mass is used here. - This value is used to make exercise prescriptions, as intensity of any cardiovascular activity is based on either the percentage of one’s vo2 or their max heart rate.2. What are some of the factors that can affect VO2 max?- Since vo2 is a measure of how efficient the body is at using oxygen, any factor that affects oxygen usage will affect vo2. Such as activity (running will achieve the highest vo2, as it uses the most muscle mass, and thus, most oxygen), amount of mitochondria, heredity (identical vs fraternal twins), gender (males have more hemoglobin and muscle mass, so females are around 15% less). Training will obviously increase it to an extent (at MOST 20% from pre-training). - Most factors are inherited around 20-30%, such as Vo2 max, blood lipid profile, total body fat etc. - Age will affect it, as it will increase in children. It is usually constant with genders up to age 12, then it will increase in boys. Adults usually reach their peak vo2 around age 25, then it will typically decline with age.Page 2 of 153. Explain some of the factors responsible for the improvement in VO2 max through exercise. Include the cardiovascular changes one might expect to see with exercise training.- Vo2max formula is CO x a-vReturn, and a-vReturn doesn’t really change in effect to training, but CO changes substantially. The increase in CO is what raises vo2. Anything that increases CO then, like increasing venous return, increases EDV via the Frank-Starling mechanism, and increasing heart contractility. - Changes that happen in the heart were covered in much detail in my last guide. Vo2 affects one’s recovery time after exercise, as a greater vo2 means more oxygen for the body=faster recovery. As one’s aerobic fitness increases, their body will make more enzymes to be more efficient, build more capillary density, and increase glycogen stores.4. How does the concept of specificity apply when talking about VO2 max? Here include; mode of exercise, subject fitness status, and different types of equipment one might use to measure VO2 max.- You want a test that will use the most muscle mass: Running. - Other tests that are not maximal treadmill runs are submaximal cycle ergometer tests. These uses a submaximal heart rate that one achieves and predicts vo2 max from it. As it is a prediction, it is not the best way to assess vo2. Vo2 is assumed to follow a linear increase with heart rate, which is not always true. Heart rate mx is required to get a submaximal heart rate, and 220 – age is not too accurate, so this can skew the tests. It also assumes that all participants have the same efficiency in cycling; not true with elites or trained cyclists. - There is also the step test. This is simply stepping to a metronome for a 3 min time test. Men seemed to test better at 24 steps. 5. What factors account for gender differences in VO2 max?- Females will always have lower vo2’s with fitness matched male counterparts. When all factors all equal, women will be around 15% lower, because their bodies simply do not have the same amount of hemoglobin. Males also have more muscle mass and less fat. Training Principles for aerobic exercise 1. Be familiar with factors which affect the aerobic training response (intensity, duration, etc).Page 3 of 15- Whenever someone makes an exercise program for someone, they use these factors to create the program, just like how when you go to the gym, you have sets and reps. For aerobic exercise, you always have the duration (length of the activity), frequency (days per week), intensity (usually a percentage of you max heart rate or vo2), and mode (type of exercise; running, swimming, biking etc). Intensity is the most important factor that can be manipulated to receive training benefits, followed by frequency. So this is saying if you work out really hard two days of the week, you will get the same benefits as someone who works out really easy four days of the week. With frequency you need at least two days a week to receive any benefits. So hitting the road to run one day a week isn’t cutting it. 2. Maintenance of aerobic fitness gains.- To maintain one’s fitness level, we can really just maintain a high intensity of exercise for as low as two days a week. This will prevent you from losing fitness.3. Understand various cardiovascular adaptations that occur with chronic training.- With training comes a lot of cardiovasular gains, thus this is the point of exercise. Your heart rate at rest will become lower, because aerobic exercise increases one’s parasympathetic input (via the vagus nerve). Resting heart rates of 35 BPM aren’t rare. The athlete will have a higher stroke volume, meaning they pump out more blood with every heartbeat. I don’t know if he talked about the mechanisms for these adaptations, so I’m not going to review them. If he did, they are in my previous guide (if
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