Lecture 7: Laboratory-Based Physiological Assessment of OA Flashcards
What is cardiorespiratory function (CRF)
Overall function of the CV (heart and blood vessels) and respiratory systems (lungs and airways)
Synonyms for CRF
Aerobic fitness
Aerobic endurance
Cardiorespiratory endurance
Two good reasons for testing CRF
- Provides baseline values prior to commencing a fitness program
- Is a key determinant of maintaining independent living (basic ADLs and instrumental ADLS)
What are the 2 ways of measuring CRF in a lab setting
- Direct method
2. Indirect method
When are direct measures taken
During maximal intensity tests
What are the advantages (2) and disadvantages (3) of the Direct measure compared to the indirect measure
Advantages:
- More accurate: typical error 3-5%
- Better estimate of desired intensity
Disadvantages:
- Require sophisticated and expensive equipment
- Higher risk of adverse events (more stress)
- Physician supervision can be required
Are direct measures more appropriate for younger healthy people or athletes compared to OA
yes
When are indirect measures taken
Taken at sub max intensities 75% HR max
Indirect measurements are taken without the use of?
Sophisticated equipment
What is used to estimated VO2 level
Equations
What are the advantages an disadvantages of the indirect method compared to the direct method
Advantages:
- Easier to make measurements
- lower risk for technical issues
- test is shorter to perform
- test is less expensive
Disadvantages:
1. Less accurate error: 10-20%
What is the different equipments for sub max CRF tests
Treadmill
Leg ergometer
Arm ergometer
Recumbent Stepper
What are the 4 considerations for choosing the treadmill test
- Expensive
- Not portable
- Difficult to measure BP vs. leg cycle ergometer (arms are moving)
- May not be appropriate for older adults with balance, gait or weight problems
Is the treadmill test functionally relevant
yes the activity mimics walking which is the most important ADL
The leg cycle ergometer is the preferred testing vs the treadmill for OA with?
Balance, gait or weight problems
Is the Leg CE easy to obtain BP and HR and is it portable
Yes
What are 2 disadvantages of the Leg CE
- Not a functional exercise - ppl who dont ride a bike regularly will have a disadvantage
- Can develop localized muscle fatigue
For non initiated OA, what may be the limit of the CRF test
The limit of the CRF test may be the use of equipment vs. their aerobic capacity
Vo2 max is what percent lower on the leg CE vs the treadmill?
10% lower
The recumbent stepper is the preferred testing for OA with?
Balance gait or weight problems
Impaired motor coordination in upper/lower limbs
What are the 4 disadvantages of the recumbent stepper
- Not really functional
- Expensive and not portable
- Difficult to take BP during test
- Recent: limited exercise protocols for testing
Can you design your own testing protocol for OA?
Obviously, especially for sub max exercise
The Arm CE is ideal for what type of OA
OA with difficulty in ambulation: Wheelchair or bed restrictions
ex: Stoke, SCI, MS etc..
What are 2 advantages of the Arm CE
- Portable
2. Relatively inexpensive
What are 3 disadvantages of the Arm CE
- Localized muscle fatigue in smaller arm muscles
- Lack of functional specificity (unless ur dealing w ppl who cant walk)
- Hard to take BP during test
There are several protocols available for using the treadmill, leg and arm ergometer, how many for the recumbent stepper
1
For OA what type of tests are recommended
Sub max
- indirect measurement of the volume of oxygen consumed per min
- participants must reach +/-75% of max age predicted HR
What is the accuracy for predicting VO2 max
- Based on the assumption that HR increases at same rate as work rate
- error of 10-20%
Is it better to compare workload/vo2 achieved at a given HR from test to test vs. extrapolating to max
Yes
Why is the Modified Balke-Ware treadmill test recommended for OA
- Uses a slow and constant walking speed with small increases in grade every minute
- Most appropriate for OA w good ambulation, however has been successful in participants w stroke and parkinsons
The MBWT test can be a bit too long for fit OA, how can it be modified
- Increase walking speed
2. Increase grade increments
What are the reasons for stopping a test (10)
- Angina like symptoms
- Participant is not sweating, feels light headed, feels confused or unsteady, looks pale, has blue lips
- BP drops below 20 mmHg from rest
- No increase in systolic BP with increase in intensity
- Excessive rise in systolic BP above 260 mmHg and or rise in diastolic BP above 115 mmHg
- HR does not rise with increase in intensity
- Participant has noticeable change in heart rhythm (arrhythmia)
- Participant requests to stop
- Participant shows physical/verbal signs of severe fatigue
- Failure of the testing equipment
What is the clinical significance of the CRF tests
For a 21 year old, they need to increase HR by 84 BPM but for a 72 year old, they need to increase HR by 46 BPM so CRF tests for OA do not have to be as vigorous and demanding as w younger people
The MBWT test is recommended for (3)
- Healthy and frail OA
- Participants w cardiac problems
- Participants w chronic diseases and disabilities
Why is theMBWT test recommended for such participants
- Walking speed is slow: 3.2 km/h / 0.9 m/s
2. Slow increase in treadmill grade
What should participants do before the MBWT test
- Record baseline HR andBP
- Calculate and record predicted HR max: (207-0.7*age) and 75% HR max
- Let the client get used to walking on the treadmill. Instruct the client to:
- Straddle the belt while holding onto the railing
- Start the belt moving at 2 miles/hr
- Let one foot get the feel of the belt speed while keeping the other foot off the belt
- While holding onto the railings, step on with both feet, stand tall and look forward
- Try to walk heel to toe with a normal gait pattern
- Use fingertip support on the handrails until comfortable on the treadmill
What should participants do during the test
- Set the treadmill speed at 2 miles/hr or 3.2 km/hr
- Speed can be 2.5 or 3 miles/hr or 4 or 4.8 km/hr for better conditioned clients - Increase the grade by 1% every minute (2% for better conditioned clients)
- Record HR and RPE at the end of every minute (2% for better conditioned clients)
- Monitor clients physical expressions and appearance and symptoms
- Stop the test when clients reach 75% HR max, request to stop or any indications for stopping are apparent
- Record HR and RPE after stopping the test
What should be done after the test?
- Reduce grade to 0%, clients continues to walk for 4 minutes
- Record HR and RPE at the end of every minute
- Record BP at the end of the 4th minute
- If the test is terminated early due to a health event, remove client immediately from the treadmill and assess their vital signs
Specific studies have found pedestrian walking speeds ranging from ___ km/hr to _____ km/hr for OA and from ____ km/hr to ____ km/hr for YA
Specific studies have found pedestrian walking speeds ranging from 4.5 km/hr to 4.8 km/hr for OA and from 5.3 km/hr to 5.4 km/hr for YA
What is the equation to calculate oxygen consumption at 75% HR max
VO2= 0.1 x speed + 1.8 x speed x grade (end of test) + 3.5
What units is the speed in
meters/min (1 mile/hr = 26.8 m/min)
what does 3.5 represent
Resting oxygen consumption (3.5 ml/kg/min)
How would you use your participants VO2 results?
- Compare result with VO2 needs (or METs) for performing ADL’s
- Pretest-posttest comparison after exercise training
What will normally change as a result of training
- Overtime there will be an increase on VO2 at the same HR level
- This indicated that the CRG is improving
Why is muscular strength important in OA
To overcome sarcopenia
What are 2 ways to asses Muscular Strength
- The 1 RM test recommended for healthy OA
2. Submax alternative to 1 RM for frail OA or participants with phys impairments and disabilities (arthritis)
During the 1 RM test, it is important to avoid _____ and decrease _______
During the 1 RM test, it is important to avoid multiple reps and decrease risk of injurt
What is the objective of the 1 RM test
To find the maximum weight a person can lift once
How many cycles of adding weight is recommended?
3-5
What is the first step of the 1 RM test
Instruct the client to warm up with light weights (half predicted max)
What is the second step of the 1 RM test
Instruct the client to complete 3 - 5 reps with a higher weight (60-80% perceived max)
What is the 3rd step of the 1 RM test
If exertion is close to max, after a 1 min rest ass weight 2.5-5 lbs or 1.1-2.3 kg which is continues until the client can complete no more than 1 rep
When is the sub max alternative to the 1 RM test used
When contraindications to max intensity (osteoporosis, hypertension, frailty, arthritis…)
Can the sub max 1 RM test be repeated in time to measure the effect of a training program
yes
Why is balance testing important in OA
Because it leads to more falls
What is balance testing defines as
The ability to control the body’s center of mass relative to the base of support (BOS), whether that base is stationary or moving
Define limits of stability (LOS)
The max distance an OA can move beyond a centered position without altering the BOS
What are the 4 measurements of balance
- Static balance
- Dynamic balance
- Reactive balance
- Sensory integration and Organization
What is static balance
The ability to maintain the COM directly over the BOS
Do OA have greater or less postural sway over their BOS
Greater
What is the static balance assessment
Stand still for a designated period of time (20-30 sec)
- Eyes open-closed
- Feet heel to toe
- One legged stance
What does a force plate measure
Magnitude and velocity of the postural sway
Where is the center of pressure placed during static standing in a hemipareitic OA
Shift toward the strong side (strong leg)
What is dynamic balance
The ability to control the COM while leaning through or moving beyond the LOS
What happens when you move beyond the LOS
You take a step
What is a dynamic balance assessment
Lean toward visual targets as quickly and accurately as possible
What to dynamic stability tests measure
- Distance reached forward, backward, laterally and diagonally
- Time of rxn
- Movement accuracy
Is dynamic stability mainly used to testing or training?
Both
What is reactive postural control
The ability to respond automatically to a loss of balance
How is perturbation elicited
Through a moving motorized force plate
How does the force plate move
forward, backward and rotates
How does a participant with good balance respond
Quickly with a counter movement opposite to the direction of plate movement
What foes the force plate measure
Time and magnitude of reaction to the perturbation
What is sensory integration and organization balance
The ability to integrate and organize sensory info provided by the visual, somatosensory and vestibular systems
What does the sensory integration and organization test measure
- How well each sensory system is functioning
2. How well the participant maintains upright balance when the info coming from the 3 systems is not in agreement
What does the results of the sensory integration and organization test indicate
If an OA is at risk of falls in certain sensory conditions (low lighting, compliant surface, busy visual environments)
