Physiology, Health & Exercise Lesson 11 zThe Principles of Exercise Testing

2 Principles of exercise testing Include: zUse of maximal and sub-maximal tests zVO 2 max zExercise stress testing zCardiac patient rehabilitation

3 Why measure physiological fitness? zTo monitor effectiveness of a training programme for an athlete zTo monitor recovery from MI

4 How to determine aerobic fitness? zMeasure maximum rate at which the body is able to take up and use O 2  maximal testing zCalled VO 2 max zMeasured in cm 3 kg -1 min -1 zHigher VO 2 max the greater the aerobic fitness of the individual

5 VO 2 max zMeasured by getting the person to run on a treadmill whilst breathing in a measured gas supply zAs intensity of exercise increased (increasing speed or gradient of treadmill) more O 2 taken in until it reaches a maximum level that does not change even if exercise intensity increased further.

6 VO 2 max

7 zOnly suitable for evaluating the fitness of competitive athletes zAlso requires expensive lab equipment, technical personnel & medical back up zInstead use sub-maximal tests

8 Sub-maximal testing zRelies on 2 assumptions: yThere is a linear correlation between VO 2 max, HR & intensity of exercise yThat an individuals maximum HR = their age zInvolves exercise at much lower intensities than maximal testing

9 Sub-maximal testing zPulse rate & O 2 uptake are measured at various levels of activity zThis data used to draw a graph of pulse rate v O 2 uptake zStraight line is drawn and then extrapolated to max HR for that age of person zVO 2 max then predicted from graph

10 Sub-maximal testing zGraph here pulse v vo2 max

11 Sub-maximal testing z2 sources of error with sub-maximal testing: yother factors than exercise affect HR e.g. temperature, anxiety, emotions, previous meal etc y220- age = maximum HR is not necessarily accurate for everyone as it is only an average

12 Typical VO 2 max values ztop endurance athletes usually have a very high VO 2 max around 70ml/kg/min  average person has a VO 2 max around 35 ml/kg/min za low VO 2 max < 25ml/kg/min usually means you would be poor at endurance events

13 Typical VO 2 max values zCan enter your own time and distance into BBC Sport Academy Fitness test website to get your own VO 2 max. For accuracy you need to have covered a distance greater than 1Km zlink to VO 2 maxlink to VO 2 max zFitness testFitness test

14 Examples of Sub-maximal tests zExamples of sub-maximal tests are: yStep tests y20-metre shuttle run yshuttle walking test

15 Step Tests zsimplest & most commonly used zuses steady-state exercise HR or recovery HR to evaluate efficiency of cardiovascular response to exercise zseveral different protocols but all based on same physiological principles

16 Step Tests ysubject steps up & down from a bench or step at a fixed rate for several minutes (3-5 mins) yheight of step & rate of stepping (set by a metronome) vary with different protocols yat end of exercise HR measured for 15-30secs at 1 min intervals for 4 mins after exercise stops  recovery rate yfitter subject is, lower HR will be immediately after exercise & faster return to resting level

17 Step Tests zcan also measure HR continuously during exercise by wearing an HR monitor zcan repeat same test after e.g. an exercise programme to indicate an improvement in fitness levels

18 20-metre shuttle run zcommonly used field test of aerobic fitness zhowever it is maximal & exhaustive zonly suitable for moderately fit individuals zsubjects run between markers positioned 20 metres apart at a pace determined by a pre- recorded tape

19 20-metre shuttle run ztest starts at a fairly slow pace which increases every minute zsubject runs between the 2 markers until they cannot keep up the pace zthe number of completed shuttles is recorded and used to predict VO 2 max

20 Shuttle walking test zsimilar to shuttle run, however subject walks zmore suitable for less fit individuals

21 Exercise stress testing zoften patients with chronic CHD have normal ECG traces at rest but abnormal ECG traces during exercise zsome heart rhythm abnormalities are triggered by exercise zcarry out stress tests on a treadmill, when workload increased at an incremental level, while monitoring their ECG zmost commonly used protocol is the Bruce Protocol zBruce protocolBruce protocol

22 Cardiac patient rehabilitation zsupervised aerobic exercise sessions are included in all cardiac rehabilitation programmes zalso offered advice on diet, smoking, alcohol, stress & relaxation zexercise programmes designed to allow patients to improve their physical fitness levels so that they can cope with the demands of everyday life zeach patient will have a tailor made programme based on their ECG but all follow same type of profile

23 Cardiac patient rehabilitation zinitially will start with gentle walking about 1 week after the heart attack or surgery z4-6 weeks later slightly more vigorous activity can be started & muscle strengthening exercises included zshown that this leads to better recovery and survival rates

24 Question Homework zDescribe the effects of exercise training on the cardiovascular system8 marks zDiscuss the principles of exercise testing 7 marks zHand in- 08/02/10