Phys Lab Flashcards
(113 cards)
Describe VO2 maximal exercise test and drawbacks
Low = increased risk of CVD and premature mortality
Direct determination via a maximal exercise test and measuring expired expired gases - O2, Co2 and gas volumes (indirect calorimetry)
Not suitable for individuals with high risk CVD
Lack of specialist equipment or trained personel
Cost of equipment and need for system calibration
Decribe the 4 methods for predicting VO2 max
The Bruce treadmill protocol - maximal graded exercise test
The Astrand - Ryhming cycle ergometer test - submaximal test
The Chester Step Test - submaximal test
Questionnaire (no exercise)
Safe conduct guidline
Complete a PAR-Q (physical activity readiness questionnaire)
Informed consent form sign
1) Ensure that the treadmill or ergometer is safe
2) Describe all procedures fully to the participant and provide a written summary (Participant Information Sheet)
3) Familiarise the participant with all equipment to be used]
4) Give the participant opportunity to ask questions
5) Ensure that the participant knows that it is his/her responsibility to inform the experimenter if they are in difficulties during the test.
6) Watch the patient closely during and 10 minutes afterwards
7) Give the participant time to warm up and cool down after exercise
behave calmly
Use simple language
Describe the Bruce Treadmill protocol and benefits/ drawbacks
Maximal exercise stress test.
Performed until exhaustion or signs and symptoms.
Duration used to predict VO2 max.
Every 3 minutes (to end of 27), % grade increased from 10 by 2 and speed increased by .8-1.5km/h.
Non invasive
Suspected heart disease patients
Can give overestimation if heavy use of handrail
What is monitored during the Bruce treadmill protocol?
HR, rating of perceived exertion (RPE), ECG, BP, clinical signs and patient symptoms.
Often difficult to measure obs
How is duration of the Bruce treadmill protocol used to predict VO2max?
Using equation
Fraction of a minute needs to be calculate (
Describe the Astrand-Rhyming cycle ergometer test
Submaximal stress test
Heart rate is used to predict VO2 max when working at a set heart rate.
A nomogram is uses gender, HR and Work load to calculate VO2 max. This is then multiplied by a correction factor to adjust for age
The participant works at 50rpm for 6 minutes. HR is taken at minute 5 and minute 6 and an average is taken.
Unconditioned male uses 300 or 600 kg.m.min-1 = 50-100Watt
Conditioned male 600-900= 100-150
Female = 300-450
cond female = 450-600
Stop at 70%HR reserve / 85% HRmax.
Goal to get HR between 125-170
PES used also
What assumptions need to be met for an accurate estimate of VO2 max (5)
1) steady state heart rate is reached for each exercise work rate
2) Linear relationship between WR and HR
3) Predicted and actual max HR are minimal difference
4) Mechanical efficiency is the same for everyone
5) No caffeine, drugs, stress, dehydration, hot as all of these affect heart rate
How is kg.m.min-1 calculated?
flywheel reveloves at 6m per revolution. 50RPM. 1kg x 6 x 50 = 300kg.m.min
Describe the Chester step test
Step in time to muscle
Low resource, don’t need specialists/ ergometers
5 x 2min stages
What does the chester step test require
CD player (metronome), HR monitor, stop watch, graph paper/nomogram, Borg 6-20RPE scale, steps
What are the heights of the step in the Chester step test
30cm <40 regular MVPA performed
25cm >40 regular MVPA performed
20cm <40 little or no activity/ moderatel overweight
15cm >40 little or no activity/ moderately overweight
>60 then 15-20cm
What should be done prior to the Chester step test
Measure resting HR Ask age Calculate predicted max HR Explain -step on and off in time with tape -Every 2 mins HR and RPE will be checked and pace will increase -Can change lead leg - Continue until 80% or RPE >=14 -Tired, dizziy, faint, breathless then stop Demonstrate technique
How is the Chester step test conducted?
Start stopwatch Ensure timing is correct Ensure patient doesn have hands on knees Take HR and RPE Repeat 3 levels are needed for valid outcome
How do you interpret Chester step test?
Plot HR on graph paper taking into accont height
Draw linear line of best fit (do not use if <50% heart rate max)
INterpolate maximal O2 from age predicted max HR
Decribe non-exercise VO2 max estimation
Used questionaires e.g. CHarles.
Uses sex, BMI, age, Percieved fitness and percieved PA
PFA - Percieved functional ability based on pace at which you could run 1 mile continuously (not too fast or slow) - just right for you = 1-13
Also pace at which could run/ walk 3 miles without getting out of breath or overly fatigued 1-13
PA-R habitual PA
1-10 based on light, mod, vig activity average over last 6 months
What can be done prior to test?
Forms and sheets ready Calibrate equipment Organsie so that same muscle group is not stressed continually Consent form Maintain temp 20-22 and humidity <60% Obtain HR, BP, height, weight, body comp Note use of BBs or drugs with HR effect
What should be done between tests?
Allow HR and BP to return to baseline
Define cardiorespiratory fitness
Ability to perform large muscle dynamic MV intensity exercise for prolonged periods of time
What physiological factors is VO2 max dependent on?
CO and arterial to venous pressure gradient
How do you know you have obtained VO2 in test?
O2 consumption at a steady state
Difference between VO2 max and peak VO2?
Peak = not O2 steady state - most pulmonary/ CVS patients
When can submax be used in MI patients
4-hrs after MI
Why is HR in submax not directly linked to VO2? one way to make this better
due to environment, diet and behaviour
e.g. allow a practice to reduce effects of anxiety.
Avoid caffeine.
Allow HR to reach steady state