Lab 4 Flashcards
what does VO2 max measure
max capacity to transport and utilize O2 during dynamic exercise – involve large muscle mass
how is VO2 max measured
using indirect calorimetry during MAX GRADED EXERCISE TEST
Energy expenditure is a function of what
work rate
what increases linearly with work rate until the VO2 max is reached
oxygen consumption
at the VO2 max an increase in work rate does what?
doesnt increase oxygen consumption (VO2 plateau)
At VO2max what does it represent
the physiological limit of body to deliever and extract O2
on a graph what does it look like when an individual has hit VO2max
point where there is a “plateau” in O2 consumption with increase in work rate
What two physiological factors is VO2 max dependent on
- max ability of cardiovascular system to deliver oxygenated blood to working tissues
- max ability of working muscle to extract O2 and produce ATP aerobically
What is the Fick Equation
describes VO2 as product of cardiac output (Q= HR x SV) and oxygen estraction [(a-v)O2 difference)
VO2max= Qmax*[(a-v)O2difference]max
- cardiac output * oxygen extraction
VO2 max is the product of what two things – how do these effect VO2 max then
cardiac output and arteriovenous oxygen difference
change in one or both variables will effect VO2max
Increased cardiac output (endurance training) is due to what
increase in maximal stroke volume
-athletes decrease SNS activity (less fight or flight because body accustomed) - more stroke volume
what three things cause an increase in stroke volume
increases in end-diastolic volume (preload) and cardiac contractility, and decrease in afterload on ventricles
Max HR does or doesnt increase with endurance training
does not increase
Increased arteriovenous O2 difference is due to what
- increase in capillary density and mitochondrial density
- biochemical and metabolic adaptations
VO2 max test requires what
using large muscle groups – specifically an athlete performing their specific event
what is the specificity principle for VO2max testing
VO2 max test should involve specific movements used by athlete in their event
treadmill tests usually have what type of effect on VO2 max vaues
greater vo2max values (~5-10%) b/c involvment of more muscle mass (upper body)
what is traditionally the most important criteria in determining one’s VO2max
plateau in oxygen consumption after increase in work rate
What are the 5 possible criteria that must be met (must have at least 2)
- plateau in rate of oxygen consumption (VO2) after increase in workload
- RER > or equal to 1.15
- Hr > or equal to (age-predicted maximal HR-10BPM) using equation HRmax = 208-(0.7*age)
- rate of perceived exertion (RPE) > or equal to 17
- blood lactate > or equal to 8mM
What does RPE mean
rate of perceived exertion - indicator of exercise intensity
What are the 4 determinants that effect VO2 max
1.genetics – VO2 max lower in females than males –> difference in HR, cardiac output, and pysical working capacity
2. sex – VO2 max lower in females –> difference in cardiac output, hemoglobin, muscle mass
3. training status – endurance training = adaptions and dependent on individuals pre-training fitness level —> trained indiviuals have smaller increase in VO2 max w/ additional training and training at moderate to high intensities appears to produce greater increase in VO2max than low intensity
4. age – VO2max decrease w/ age b/c reduce max cardiac output and max (a-v)O2 difference –> max HR decrease linearly w/ age and endurance doesnt slow decline in max hr with aging – muscle mas decrease w/ age
What is the lactate threshold
point where blood levels of lactate begin to rise exponentially
What is the ventilatory threshold (VT) for lactate threshold
sudden increase in ventilation – marker of lactate threshold but not necessarily related
when does the lactate and ventilatory threshold occur in trained and untrained individuals
untrained: 50-60% vo2max
trained: 65-80% vo2max
