Aerobic Assessment 2 Flashcards
Running (exercise) economy is influenced by internal factors such as…
- joint biomechanics
- respiratory entertainment
- VO2 drift
Running (exercise) economy is influenced by external factors such as…
- wind resistance
- friction
- energy absorption (eg. shoes)
- external load (eg. clothing)
Ultra endurance athletes may have similar VO2 max as middle distance athletes but the latter cannot match _____ _____.
aerobic capcity
Why measure aerobic capacity?
- may be more important to the individual than other physiological variables used to assess aerobic fitness, especially for exercise prescription
- may have an athlete and clinical/health application
- capacity of the aerobic system may have more application to ADL than aerobic power
Aerobic capacity:
the total amount of work that can be done using aerobic energy sources
Aerobic capacity tests ned to be of a sufficient _____ to determine/predict the limits of _____ _____ ____.
- duration
- aerobic power output
It is very difficult to determine _____ with aerobic capacity.
validity
Aerobic capacity is dependent on:
- hydration
- glycogen (energy stores)
- lactate clearance
- muscle soreness
Aerobic capacity assessments include:
- Boulay et al. “Aerobic Capacity Test”
- anaerobic threshold
- submaximal endurance tests
Boulay’s aerobic capacity test procedure:
- 90 min continuous exercise on a cycle ergometer
- intensity set at a HR 10 bpm below previously determined anaerobic threshold
- pedal revs no less than 60
- resistance adjusted throughout the test to maintain the HR intensity
- results expressed as the total kJ/kg attained
Rationale for Boulay’s test:
- VO2 does not predict the maximal amount of energy that can be generated aerobically
- 90 min significantly stresses mechanisms related to aerobic energy production
- duration also does not require intake of food
- intensity does not engage anaerobic glycolysis if set below AT
Reliability of Boulay’s test:
- ICC for relative work done (kJ/kg) = 0.99 and 0.93 for mean HR
- test retest varied less than 2.5%
Limitations of Boulay’s test:
- length of test
- requires determination of AT prior to test (not practical)
- requires precise control of resistance
- dehydration and CV drift may negatively influence results
- substrate (glycogen) depletion may influence score
- lack of comparative data available
The exercise VO2 above which anaerobic high-energy production supplements aerobic high-energy production with a
consequential lowering of the _____ _____ _____, increase in ____ ____ ____ and net increase in ____ ____ at the site of anaerobiosis.
- cellular redox state
- lactate/pyruvate (L/P) ratio
- lactate production
AT has 2 primary components:
- lactate threshold
- ventilatory threshold
Lactate threshold:
- graded, incremental protocols to near max
- should use 3-4 min increments to accurately determine blood lactate levels
- requires equipment to determine blood lactate
Most common graphical method for single lactate threshold determination:
BLa vs power output or time
Single lactate threshold:
point that precedes a sustained change in BLa greater 1.0 mM
Regression analysis for single lactate threshold determination:
LT is the interaction of 2 regression lines formed above and below inflection
The D-max method for single lactate threshold determination:
largest deviation between the La vs W curve and the line connected the end points
Onset of blood lactate (OBLA) of _____.
4 mM
MLSS =
maximal lactate steady state
MLSS tests assess the maximal ____ that can be maintained (increase _____).
- BLa
- < 1.0 mM
MLSS tests requires a series of tests at different _____ preceded by a ____ test.
- intensities
- LT
- often requires several days
Ventilatory threshold:
- graded, incremental protocols to near max
- increments can be 2-3 minutes
- requires equipment to measure ventilatory responses
Ventilatory threshold determination: Threshold analysis: _____ method most common.
V slope method (VCO2 vs VO2)
In general when assessing anaerobic threshold, ____ usually occurs at a similar time or precedes ____ by one workload.
- LT
- VT
Reliability of anaerobic threshold assessment:
- objective criteria (mathematical) test retest r = 0.95
- subjective criteria (visual) r = 0.65
If the intensity of exercise below AT is considered to be attained primarily through ____ _____ sources and above AT, there is and increased need for energy from ____ ____, then AT may set the upper limit for AC.
- aerobic energy
- anaerobic glycolysis
Below AT, exercise endurance time is greatly _____ and above AT, greatly ______.
- increase
- reduced
Endurance athletes competing in events stressing the capacity of the aerobic system have hight _____s.
AT
Field testing anaerobic threshold uses _____ intervals of exercise of increasing _____ over a ______ distance and measures ____ and actual _____ at the end of each interval.
- repeated
- speed
- predetermined
- HR
- velocity
How to use field testing anaerobic threshold:
- graph HR vs velocity and determine the deflection (breakaway) point in HR response
- predicts AT
Concurrent validity of field testing anaerobic threshold:
r = 0.93 between Conconi and actual AT
Reliability of field testing anaerobic threshold:
test retest r = 0.90
Can anaerobic threshold predict performance?
- attempted to predict marathon finishing time from AT measurements
- approx 15 second difference
Submaximal endurance:
the ability to exercise at less than maximal for a period of time
Can other submaximal tests indicate aerobic capacity?
- usually requires attainment of steady state
- usually set at an absolute or relative (per kg) workload
- variables include time, distance or some sort of physiological variables (HR, LA, work, PO, distance, time to exhaustion)
The PWC170 test:
- physical work capacity at a HR of 170 bpm
- suggests to be a capacity test
- 2 consecutive 6 min PO’s on a cycle ergometer at 50-60 rpm
- HR between 120-140
- plot HR vs PO and extrapolate to HR of 170 and determine the PO at 170 or PWC 170
Limitations of submaximal endurance tests of aerobic capacity:
- usually not long enough to stress AC
- variables selected may not indicate AC
- possible that some submax test intensities are higher than AT (so are they AC tests?)
Joyner (1991) used 3 physiological parameters to estimate the limits of marathon performance:
- VO2 max
- lactate threshold
- running economy
VO2 max:
the maximal amount of oxygen taken up and used by working muscle
Lactate threshold:
the exercise intensity at which lactate accumulation exceeds clearance
Running economy:
the amount of VO2 used for a given work intensity (ie. running speed)
Joyner (1991): maximal predicted performance:
- 1:57:48
- for an athlete that encompassed elite characteristics for all 3 physiological variables
What happens to the heart during exercise?
- HR increases
- increase preload (inc. venous return and SV)
- increase contractility
- increase Q
- decrease in time of cardiac cycle (influences filling and amount of oxygen that gets to the heart during diastole)
Cardiac factors that effect cardiac output:
- HR
- myocardial contractility
Coupling factors that effect cardiac output:
- preload
- afterload
