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Physiology, Health & Exercise
Lesson 11The Principles of Exercise Testing
2
Principles of exercise testing
Include: Use of maximal and sub-maximal tests VO2 max
Exercise stress testing Cardiac patient rehabilitation
3
Why measure physiological fitness?
To monitor effectiveness of a training programme for an athlete
To monitor recovery from MI
4
How to determine aerobic fitness?
Measure maximum rate at which the body is able to take up and use O2 maximal testing
Called VO2 max
Measured in cm3kg-1min-1 Higher VO2 max the greater the aerobic
fitness of the individual
5
VO2 max
Measured by getting the person to run on a treadmill whilst breathing in a measured gas supply
As intensity of exercise increased (increasing speed or gradient of treadmill) more O2 taken in until it reaches a maximum level that does not change even if exercise intensity increased further.
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VO2 max
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VO2 max
Only suitable for evaluating the fitness of competitive athletes
Also requires expensive lab equipment, technical personnel & medical back up
Instead use sub-maximal tests
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Sub-maximal testing
Relies on 2 assumptions: There is a linear correlation between VO2 max,
HR & intensity of exercise That an individuals maximum HR = 220 - their
age
Involves exercise at much lower intensities than maximal testing
9
Sub-maximal testing
Pulse rate & O2 uptake are measured at various levels of activity
This data used to draw a graph of pulse rate v O2 uptake
Straight line is drawn and then extrapolated to max HR for that age of person
VO2 max then predicted from graph
10
Sub-maximal testing
Graph here pulse v vo2 max
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Sub-maximal testing
2 sources of error with sub-maximal testing: other factors than exercise affect HR e.g.
temperature, anxiety, emotions, previous meal etc
220- age = maximum HR is not necessarily accurate for everyone as it is only an average
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Typical VO2 max values
top endurance athletes usually have a very high VO2 max around 70ml/kg/min
average person has a VO2 max around 35 ml/kg/min
a low VO2 max < 25ml/kg/min usually means you would be poor at endurance events
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Typical VO2 max values
Can enter your own time and distance into BBC Sport Academy Fitness test website to get your own VO2 max. For accuracy you need to have covered a distance greater than 1Km
link to VO2 max
Fitness test
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Examples of Sub-maximal tests
Examples of sub-maximal tests are: Step tests 20-metre shuttle run shuttle walking test
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Step Tests
simplest & most commonly used uses steady-state exercise HR or recovery
HR to evaluate efficiency of cardiovascular response to exercise
several different protocols but all based on same physiological principles
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Step Tests
subject steps up & down from a bench or step at a fixed rate for several minutes (3-5 mins)
height of step & rate of stepping (set by a metronome) vary with different protocols
at end of exercise HR measured for 15-30secs at 1 min intervals for 4 mins after exercise stops recovery rate
fitter subject is, lower HR will be immediately after exercise & faster return to resting level
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Step Tests
can also measure HR continuously during exercise by wearing an HR monitor
can repeat same test after e.g. an exercise programme to indicate an improvement in fitness levels
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20-metre shuttle run
commonly used field test of aerobic fitness
however it is maximal & exhaustive only suitable for moderately fit individuals subjects run between markers positioned
20 metres apart at a pace determined by a pre-recorded tape
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20-metre shuttle run
test starts at a fairly slow pace which increases every minute
subject runs between the 2 markers until they cannot keep up the pace
the number of completed shuttles is recorded and used to predict VO2 max
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Shuttle walking test
similar to shuttle run, however subject walks
more suitable for less fit individuals
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Exercise stress testing
often patients with chronic CHD have normal ECG traces at rest but abnormal ECG traces during exercise
some heart rhythm abnormalities are triggered by exercise
carry out stress tests on a treadmill, when workload increased at an incremental level, while monitoring their ECG
most commonly used protocol is the Bruce Protocol
Bruce protocol
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Cardiac patient rehabilitation
supervised aerobic exercise sessions are included in all cardiac rehabilitation programmes
also offered advice on diet, smoking, alcohol, stress & relaxation
exercise programmes designed to allow patients to improve their physical fitness levels so that they can cope with the demands of everyday life
each patient will have a tailor made programme based on their ECG but all follow same type of profile
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Cardiac patient rehabilitation
initially will start with gentle walking about 1 week after the heart attack or surgery
4-6 weeks later slightly more vigorous activity can be started & muscle strengthening exercises included
shown that this leads to better recovery and survival rates
24
Question
Homework Describe the effects of exercise training
on the cardiovascular system 8 marks
Discuss the principles of exercise testing7 marks
Hand in- 08/02/10