Lab 4: Aerobic Fitness Flashcards
what does the VO2 max test measure?
the maximal capacity to transport and utilize oxygen during dynamic exercise involving a large muscle mass
how is VO2 max measured?
via indirect calorimetry during a maximal graded exercise test
how does oxygen consumption change in relation to work rate?
oxygen consumption increases linearly with work rate until VO2 max is reached
once VO2 max is reached, does an increase in work rate increase oxygen consumption?
no
what does VO2 max represent?
the physiological limit of the body to deliver and extract oxygen
how can VO2 max be visualized on a graph?
when there is a plateau in oxygen consumption with an increase in work rate
what 2 physiological factors is VO2 max dependent on?
1) the maximal ability of the cardiovascular system to deliver oxygenated blood to working tissues
2) the maximal ability of the working muscles to extract oxygen and produce ATP aerobically
how does the Fick equation determine VO2 max?
determines VO2 max as a product of cardiac output and oxygen extraction (arteriovenous oxygen difference)
how do training adaptations increase VO2 max?
by increasing either cardiac output or arteriovenous oxygen difference
increased cardiac output volume seen following endurance training is due to..
increase in maximal stroke volume
how is stroke volume increased following endurance training?
increase in end-diastolic volume (or preload) and cardiac contractility & decrease in afterload on the ventricles
does maximal heart rate increase with endurance training?
no
how might arteriovenous oxygen difference increase?
increased capillary density and mitochondrial density, as well as biochemical and metabolic adaptations
what is the specificity principle?
VO2 max test should ideally involve the specific movements used by the athlete in their event (trained cyclist uses a cycle ergometer)
why do treadmill tests generally produce greater VO2 max values?
involves more muscle masses (upper body)
what is the most important criteria in determining one’s VO2 max?
a plateau in oxygen consumption after an increase in work rate
at least 2 of the following criteria must be met to determine VO2 max, what are the criteria?
1) plateau in rate of oxygen consumption (VO2) following an increase in workload
2) RER > 1.15
3) HR > age predicted maximal HR -10
4) rate of perceived exertion (RPE) > 17
5) blood lactate > 8 mM
what is the rate of perceived exertion (RPE) scale? how is it used?
the RPE scale is a valid indicator of exercise intensity and it was developed to predict the HR of a 20 y.o. at a given work rate by multiplying the RPE by ten (HR is approx. 60 bpm at RPE of 6)
4 primary factors the affect an individual’s oxygen consumption
1) genetics
2) sex
3) training status
4) age
how does VO2 max for females compare to that for males?
VO2 max for females tends to be lower because of differences in cardiac output, hemoglobin, and muscle mass
what kind of training produces the greatest increase in VO2 max?
moderate to high intensities rather than low intensity training
how does VO2 max change with age? why?
VO2 max decreases with age due to reductions in maximal cardiac output and maximal O2 difference
how does maximal HR change with age?
decreases linearly with age
how does endurance training affect the decline in HR with aging?
it doesn’t
how does muscle mass change with age?
decreases
what is lactate threshold
the point at which blood levels of lactate begin to rise exponentially
how might lactate threshold be measured if we can’t measure blood lactate?
via the ventilatory threshold; the point at which there is a sudden increase in ventilation, which is an estimate of the lactate threshold
where do the lactate/ ventilatory thresholds occur in untrained individuals?
50-60% VO2 max
where does the lactate/ ventilatory threshold occur in trained athletes?
65-85% VO2 max
what is exercise/running economy?
the oxygen cost of exercise at a given speed (running) or power output (cycling)
what factors influence movement economy
body mass, terrain, footwear, stride length
when comparing individuals running at the same submaximal speed, the individual with the greatest movement economy…
consumes the least oxygen, it “costs” less O2 to run at that speed
what is an athlete’s 10,000 m race pace correlated to?
their speed at lactate threshold
describe the procedure
students in 3 groups (only one group exercising at a time); exercising student chooses either the treadmill or bike, subject gets a warmup phase
treadmill: start at 3.5 mph then increase until 70% of student’s max HR is reached, then stop the treadmill and set up equipment, each stage of test is 2 mins long, the incline is raised 2% each time until max incline of 10% reached
bike: warmup at a workload that elicits HR of < 130 bpm, start test at predetermined kp and 80 rpm (subjects must stay at 80 rpm), each stage is 1 min long and the kp is increased by pre determined amount until volitional fatigue
