Lab Exam 1 Flashcards
define energy
the capacity to do work
what is the independent variable in a graded exercise test
work rate
what is the independent variable in a constant work rate exercise?
time
examples of absolute measurements
0.25 L/min or 1000 W
examples of relative measurements
3.5 mL/kg/min or 12 W/kg
how is relative aerobic power expressed
%VO2 max
rate of heat production is proportional to what?
metabolic rate
when is indirect calorimetry valid?
only when energy comes from oxidative pathways
VO2 is proportional to what?
energy expenditure during aerobic tasks
equation for gross efficiency
mechanical power / metabolic power
why is gross efficiency never 100%?
human machine is not efficient because some energy is lost as heat
what factors influence gross efficiency
work rate, cadence, fiber type, contraction type
what is the dynamic energy balance equation
rate of change of energy stores = rate of change of energy intake - rate of change of energy expenditure
factors that affect basal metabolic rate
fat-free mass, age, sex, body fatness, genetics, caloric restriction/starvation, exercise
what is resting basal metabolic rate
3.5 mL/ kg*min = 1 MET
what factors determine fuel selection?
1) intensity
2) duration
3) training status = increase oxidative capacity
4) diet - CHO supplementation (timing is important)
how does training status affect fuel selection?
“crossover” point shifts RIGHT (happens at a greater VO2 max) so you increase fat utilization, increased mitochondrial and capillary density, increased FFA transport and oxidation, and glycogen sparing
how does consuming CHO before or during exercise affect fuel selection?
increases CHO utilization and decreases fat utilization
how does consuming a high CHO diet in general or a high fat diet in general affect fuel selection?
increases CHO utilization during submaximal exercise, whereas consuming a high fat diet increases fat utilization
what is the Fick equation
VO2 = Q x (a-v)O2 difference
how do we use the Fick equation to determine VO2 max?
VO2 max = maximal cardiac output x (maximal a-v O2 difference)
how does an increase in max stroke volume affect VO2 max?
increases VO2 max
how does an increase in (a-v) O2 difference max affect VO2 max?
increases VO2 max
how does an increase in max HR affect VO2 max?
because an increase in heart rate is accompanied by less filling time and therefore decreased stroke volume, VO2 max does not really change
why is VO2 max lower in women?
women have a decreased cardiac output, decreased hemoglobin, and decreased muscle mass compared to men
what kind of training increases VO2 max?
moderate to high intensity training
why does the percent change in VO2 max with training differ among individuals?
dependent on individual’s pre-training fitness level
what are “anaerobic” energy sources? what is the better term?
ATP/PC and non-oxidative glycolysis; better termed “immediate” energy stores
what enzyme performs this reaction: ATP + H2O —> ADP + Pi
ATPase
what enzyme performs this reaction: CP + ADP —> ATP + C
creatine kinase
what enzyme performs this reaction: ADP + ADP —> ATP + AMP
adenylate kinase
potential factors that may limit anaerobic performance
1) energy depletion (Pcr)
2) metabolite accumulation (H+ ions, inorganic phosphate)
3) central and peripheral fatigue
how does training improve anaerobic performance?
increasing type 2 skeletal muscle fibers, improving the ATP-PCr system, and improving glycolysis system
does aerobic training improve anaerobic performance?
yes, because all 3 energy systems are active
T/F: increase in cardiac output with endurance training is due to the ability to get higher max heart rates
FALSE
what 2 conditions does O2 consumption represent total energy expenditure?
submaximal, steady state
T/F: the wingate test can accurately and reliably measure anaerobic energy production
false
T/F: all constant work rate exercise is at steady state
false
if an individual were trying to lose weight, would it be more advantageous to have a higher or lower gross efficiency?
gross efficiency = mechanic power/ metabolic power
to burn more calories, we want to increase metabolic power, because metabolic power is inversely proportional to gross efficiency, gross efficiency would be lower
what is the dominant energy system at 5 seconds of anaerobic exercise?
immediate (ATP-PC)
what is the dominant energy system at 20 seconds of anaerobic exercise?
nonoxidative glycolytic
by what mechanism might skeletal muscle hypertrophy increase the maximal power generated by a muscle?
by increasing surface area of muscle, you can increase the maximal amount of cross bridge formation
how might the effects of skeletal muscle hypertrophy on power be limited if metabolic enzymes didn’t also increase?
even if we have more muscle mass, if we don’t have an accompanying increase in metabolic enzymes, we cannot increase energy production via either glycolytic systems or the ATP-PC system
how does an increase in cardiovascular and muscular fitness due to aerobic training affect an individual’s performance on the Wingate test?
this would improve an individuals Wingate performance because they could use more oxidative energy sources and spare immediate energy stores for peak power output
when is it true that you burn more total calories of fat at a lower intensity compared to a higher intensity?
when the change in total energy expenditure is small in comparison to the decrease in % relative contribution of fats
when is it true that you burn less calories from fat at a lower intensity as compared to a higher intensity?
when the change in total energy expenditure is large in comparison to the decrease in relative % contribution from fats
how much air do you lose when analyzing gas using PARVO?
.35 L / min
