aerobic assessment Flashcards
1
Q
assessing energy systems
A
- high power/short capacity: anerobic alactic + lactic
- lower power/low capacity : aerobic
- the power and capacity of energy supply is dependent on the intensity and duration of the exercise bout
- we can only assess which energy system predominates
2
Q
power vs. capacity
A
- power is the maximum rate at which energy can be utilized
- capacity is the total number of work that can be performed
3
Q
interpreting aerobic system function (vo2)
A
- it is important for performance (aerobic sports) and health
- VO2 is a strong predictor of morbidity + mortality
- comes from how much work an individual can do in daily life
- high aerobic capacity is important for ADLs
- there is a difference in O2 in relation to exercising at different altitudes
- harder to exercise at high altitudes
4
Q
first laboratory exercise test
A
- measured increased consumption of “vital air” during sustained exercise
- continuation of work = more vital air
5
Q
how vo2 max was born
A
- demonstrated that oxygen uptake increased linearly with running speed but eventually reaches a maximum beyond which no effort can drive it
6
Q
why is the aerobic system important
A
- important for performance for aerobic sports and health
- can somewhat predict success in endurance activities
- can sometimes indicate the ability to recover from task
- has been linked to increased risk for a variety of diseases
7
Q
assessing aerobic power
A
- gold standard is considered to be the maximal oxygen consumption test or VO2 max test
- single best measure of overall aerobic fitness
- defined as the maximum rate at which O2 can be inspired, transported and utilized to perform muscular work
- defined by the Fick equation
8
Q
Fick equation
A
- difference between arterial + venous blood in circulation X Cardiac output
- best way to calculate VO2
9
Q
absolute vo2
A
- total volume of O2 taken up by the body in L/min
10
Q
relative Vo2
A
- volume of O2 taken up by the body per unit of body weight (ml/kg/min)
- try to use lean body mass in this equation as it is more accurate
11
Q
metabolic cart
A
- a metabolic measurement system
- is the “gold standard”
- measures how much O2 goes in and out of the system (inspired vs expired)
- volume of breath
12
Q
treadmill Vo2 measurement
A
- calibrated modality
- uses more muscle mass than the other modalities = higher volume
- considered the “gold standard” machine for elicitin vo2 max
- elicits Vo2 max 5-11% higher than cycling
13
Q
fatigometer
A
- Harvard lab experiment
- tested how work activities affected individuals
- engaged both upper and lower limbs
14
Q
similarities between the 9 treadmill protocols
A
- incremental increases in workload
- workload increased by grade (inclination)
- stages at 2 minutes usually indicate steady state
- total time is usually 12 minutes
- all test aerobic power
- protocols that increase speed only are NOT recommended
15
Q
speed only vs grade only vo2 max
A
- speed mean vo2 max = 46.2 ml/kg/min
- grade mean vo2 max = 62.6 ml/kg/min
- gives a higher outcome so many tests use grade (25%)
16
Q
modifications for Vo2 max tests
A
- slower initial speed for inexperienced
- can start with walk and increase speed first and then % grade after
- many different starting protocols are available
17
Q
end of test criteria for VO2 max tests
A
- peak and plateau less than 150ml/min in O2 consumption with an increase in work rate
- a respiratory exchange ratio greater than 1.15 (anerobic metabolism)
- achievement of predicted maximum HR (HR max)
- venous lactate concentration greater than 8mM
- RPE greater than 17 (6-20 original) or to 10
- giving up by choice / exhaustion
18
Q
contraindications of a VO2 max test
A
- drop in systolic BP of 10mmHg with increase in workload or dizziness , near fainting
- hypertensive response (blood pressure >250/115mmHg) (usually in high risk patients)
- chest pain or angina
- signs of poor perfusion (blueness in lips and whiteness in the face
- abnormal ECG recording
- cramping, extreme fatigue
19
Q
“true” Vo2 max
A
- must utilize a large overall muscle mass
- requires working against gravity (non body mass supported)
- this is accomplished on a treadmill most of the time
- can get higher Vo2 maxes with different ergometers
20
Q
“peak” vo2 max
A
- all other exercises machines/modalities
- supramaximal load
- 1 main stage at a higher intensity to see if you actually reached peak or not
21
Q
is the test data valid?
A
- machine needs to be calibrated correctly + normative values
- post gas check (gas analyzers)
- do the parameters follow the desired trends
- VE, FECO2, FEO2, VO2- are these close to expected/normative values?
22
Q
variability in VO2 max testing
A
- Katch: roughly 3-5 ml/kg/min for a 50 ml/kg/min individual
- thoden: +- 3 ml/kg/min for athletes
- reliability: test retest r=0.96 for rowing Vo2 max
23
Q
vo2 max testing in the field
A
- running , swimming, vo2 master face mask with high validity
24
Q
what if you don’t have a metabolic cart for Vo2 testing?
A
- a variety of protocols and formulas exist to predict vo2 max
- can be either maximal or submaximal
- use some sort of physiological performance indicator in a formula to provide predicted or peak VO2 max
25
maximal VO2 tests
- pushing people to Vo2 max but not measuring VO2
- leger
- bruce + modified bruce
- balke
- cooper
26
indirect calculations of VO2
- ones for running, walking , leg cycling , arm cycling, stepping
27
other maximal indirect tests
- multi-staged
- treadmill preferred (5-11 % higher than the bike)
- good estimation of true vo2 max
- protocol can be adapted for many populations
28
the Bruce treadmill test
- a continuous, progressive exercise test to fatigue
- correlated well to actual Vo2 max
- starts at 10% grade and 1.7 mph, increase speed at grade every 3min
- time to exhaustion is recorded
29
calculating vo2 max from the Bruce test
1. using a nomogram which aligns exercise time with predicted , based on time lasted within test
2. using participant specific equations ( males, females, and cardiac patients/elderly)
30
the Naughton Treadmill test
- a continuous progressive exercise test to fatigue (volitional exhaustion)
- specific to higher risked individuals
- starts at 05 grade and 1.0mph
- increase speed at 2 min (2mph) and grade (+3.5%) every 2min
- time to exhaustion is recorded
31
cycle ergometry
- can be continuous or discontinuous
- minimize fatigue and rest stage
- max power output (W) attained is used to estimate VO2
32
leger 20 meter shuttle run test
- Vo2 max -24.4 + 6.0 (MAS)
- MAS = max aerobic running speed in km/hr
33
cooper 12 min run test
- Vo2 max = 22.35 x distance (m) - 11.288
34
submaximal tests for VO2 max
- uses more information and have to calculate where they would end up at max
- mCAFT
- YMCA
- Astrand
- PWC
- ACSM
- Ebelling
- Rockport
35
why use predictive submaximal VO2 max tests
- safe, avoids a maximal cardiovascular stress, usually for lower risk individuals
- relatively inexpensive
- less sophisticated equipment required
- less expertise required
- more conductive to "mass" testing
- some test protocol durations are shorter than maximal protocols
36
what are submaximal tests for predicting VO2 max based on
- the positive linear relationship between power output, increased VO2 and HR
- the assumption that MAX HR can be predicted similar in all individuals
- assumption that variability in heart rate (day-day) is minimal
- the assumption that efficiency of exercise is similar between individuals at max
- best predictive power using HR occurs between HR's 120-170b/min
37
predicting VO2 max using a multi-stage equation
- using weight, heart rate and , age
1. determine power output for each stage (VO2 = watts/body mass x 11 + 3.5)
2. determine slope for line of best fit (b = vo2 submax 2 - vo2 submax 1) / (HR2-HR1)
3. determine VO2 max
38
predicting vo2 max by graphing
- use metabolic equations to calculate VO2 for each stage
- Plot HR (end stage; 3rd min only) vs calculated VO2 and extrapolate to age predicted HRmax
- use line of best fit
39
ebbeling treadmill test
- single stage protocol designed for healthy adults (20-59 yrs)
- 4 min warm up at 2-4.5 mph & 0% grade
- HR should be btw 50-70% of HR max
- individual exercised for an additional 4 minutes at 5% grade (same speed at warm-up)
- equation used speed, HR, age, and sex
40
rockport 1-mile walk test
- created for males and females from 20-69
- may be more appropriate for older and sedentary populations
- one mile (1.6 km) track (not treadmill) is required
- instruct the patient to walk the 1 mile as quickly as possible w/o speed walking
- measure HR at end of test
- need weight (lbs), age, sex, time, HR
41
general protocol for submaximal tests
- warm-up for 5 min at low intensity
- 20-30% HR reserve or 35-45% of age-predicted Max HR
- monitor HR, BP, RPE, symptoms prior to, during and after exercise ( 1, 3, 5 min)
- most protocols do not include post-exercise monitoring recommendation in their description
- critical competency
warm/cool-down (active recovery for 5-10 min)
42
critical competency
- ability to measure resting and post-exercise blood pressure
- ability to measure resting, steady state exercise, and post-exercise heart rate via palpation
43
limitations to submaximal tests
- other factors affecting HR (anxiety, temp, caffeine, talking, body position)
- achievement of steady state (some individuals need longer stages to reach steady state)
- age predicted maxHR formulas have a degree of error, 220-age does not hold up in all populations
- 208 - 0.7 x age in yrs is more accurate
- predicted HR max can vary 10-12 beats
-over/underestimation for athletes, sedentary , and older populations
44
stress tests
- tests cardiac function by increasing HR and myocardial contractility
- best way to look at issues within the heart
- when you exercise , HR increases and so does contractility, and BP
- the heart then has to work against a higher BP which increase stroke rate + cardiac work + increased O2
45
incremental exercise protocol
- 12-lead ECG and BP measurements
- looking for heart abnormalities
- subjective symptoms ( borg, angina, claudication scale)
- claudication scale determines artery pain = poor perfusion
46
why have a stress test
- completed as a part of an annual checkup or physical used for screening as part of physician screening
- prognostic: assessing patients with risk factors
- diagnose : coronary artery disease & symptoms such as chest pain, shortness of breath or lightheadedness
- functional: to assess a procedure that may be used to improve coronary artery circulation
- functional: to determine a safe level of exercise for rehab or daily living , includes all individuals, included lower and below test intensities
