Unit 8: Aerobic Performance Flashcards
Aerobic Activity
-a task that you can sustain over a long period of time
-Oxygen is the main source of energy - you breathe faster and deeper than normal so that your blood is supplied with oxygen and your HR increases which increases blood flow to your working muscles and back to your lungs
Aerobic energy system
sustained activity with oxygen system
Maximal aerobic power
the highest amount of chemical energy that can be transformed in the aerobic machinery of muscle mitochondria per unit time and can be measured as maximal O2 uptake
Aerobic capacity
denotes the total chemical energy available to preform aerobic work
How do you measure aerobic capacity
we can use surrogate variables such as endurance performance, time to exhaustion or bioindicators
Limitations in measuring maximal aerobic power
-estimates of aerobic performance that are not also influenced by anaerobic energy production are rarely possible to obtain
-but when exercise is low to moderate intensity or when it lasts for 8-10 minutes at least, the contribution of non-oxidative pathways to the energy needs of the working organism is quite small
VO2 Max test
a maximal exercise test performed on a treadmill or bike while connected to a machine capable of analyzing your expired air
-provides data on how much oxygen you use as you exercise and determines the maximal oxygen you can consume during exercise
Benefits of VO2 max test
-accurate measurement of current fitness level
-evaluation of effectiveness of a training program
-prediction of maximal steady-state running speed/incline or cycling wattage
Measurement Issues for VO2 max testing in children
- Important to obtain full cooperation from the child
- Getting this cooperation will require explaining the test using age appropriate terms
- Familiarization to the protocol equipment
- Encouragement during the test itself (especially during the last 2-3 minutes of the test)
What factors must be considered when using the same ergometers in children that are commonly used in adults
-moving seat closer to pedals
-pedal shaft shortened
-in adults musical metronome can be used but for children visual or auditory cues are easier for them
Treadmill vs. Cycling Ergometer
Running on a treadmill uses a larger muscle mass than pedaling on a cycle ergometer
VO2 max 10% lower on cycle ergometer
Arm vs cycle ergometer
arms achieve 60-70% of what is achieved through cycling
Disadvantages of using a treadmill for VO2 max testing
-risk of tripping
-requires additional research assistant
-some children will terminate test prematurely due to fear
Treadmill running in children
-many labs use treadmill for children under 10
-even as young as 5-6 years old can master treadmill running after 3-5 minutes
-some children take several trials
Attention span during VO2 Max testing
children have short attention spans
tests of maximal aerobic power should not exceed 8-10 minutes
initial work rates and the increments must be carefully planned out
Criteria for achieving maximal O2 uptake
-heart rate of 220 beats/min - age
-respiratory exchange ratio of 1.05 of higher
-plateau in VO2 Max: only 40-50% of them achieve - max effort can be assumed without the plateau
Fick Equation
VO2=Q(CaO2-CVO2)
VO2 = O2 Uptake
Q= cardiac output (HR x SV)
CaO2 and CVO2 = the content of oxygen in the arterial and mixed venous blood
Cardiovascular responses during aerobic exercise
Increase cardiac output due to increased heart rate
Cardiovascular responses during growth
dimensions of the heart enlarge with age and with out growth in body mass
-increase in size is associated with an increase in stroke volume
-despite HR decline Q increases
Economy of movement
reflects the metabolic cost of performing a certain physical task
Why is the economy of walking and running higher in young children
-mechanical cost of locomotion may be higher in children
-could be attributed to smaller persons having shorter strides
-frequency of strides is more demanding
-Could also be a result of co-activation
-7-8 year old were seen to have distinctly more co-contraction in knee and calf antagonists than older groups
What is maximal aerobic power related to
sex, body size, maturity status of children and adolescents
Calculating Maximal aerobic capacity
Flick equation can be modified to maximal values to determine VO2 max
Max Heart rates and breathing
-highest in children (195-205)
-decline with age
-Max rate in adolescence is 190-195
-size of heart increases during growth and the increase generally proportional to body mass
-VO2 max is highly correlated with the absolute size of the heart
-Maximal pulmonary ventilation increases with age
-children have higher breathing frequency but a shallower breath volume
-increased capacity of oxygen transport system
