Exercise physiology notes from lab Flashcards
What is running economy?
The Vo2 required to run at sub-maximal speeds
What’s the lactate threshold?
The running speed at which the first increase in blood {Lactate} above baseline values occurs
What’s the lactate turning point?
Is the running speed at which there is a sudden and sustained breakpoint in blood {lactate}
Just before graph ramps up
What is a wind gate test?
Measures high-intensity, anaerobic of energy generation
What occurs at the extremes of exercise intensity?
ATP is broken down quickly to release energy required to sustain muscular contraction
The rate of consumptions exceeds production aerobically in the mitochondria via oxidative phosphorylation
A matter of second ATP is regenerated via phosphocreatine system providing a lot of energy
Power output drops very quickly
Don’t become immediately exhausted due to substrate level phosphorylation and the anaerobic portion of glycolysis
Why is the measurement of the electrical activity of the heart possible?
Body fluids contain electrolytes which are good electrical conductors
Electrical impulses generated in the heart are conducted through body fluids to the skin
Describe blood pressure?
The pressure exerted bu the blood on the vessel walls
The term usually refers to arterial blood press
Systolic blood pressure and diastolic blood pressure are the factors we measure
Mean arterial pressure = 2/3 DBP + 1/3 SBP
Typical ECG response to exercise?
Minor changes in P wave form
Superimposistion of P and T waves of successive beats (starts to look like an “M”
Slight decrease in R wave amplitude
Q wave may be deeper
Increase in T wave amplitude
Minimal shortening of QRS complex
Depression of J point (the J point is found where the S wave makes its sharp deviation (right hand turn) toward the T wave
At rest the J point should come back to the isoelectric line
Rate related shortening of QT interval
What is a GXT? (graded exercise test)
Incremental exercise test to volitional exhaustion
The test may be performed on any ergometer; cycle, treadmill, rower, kayak etc.
begins at an easy intensity, and becomes progressively harder until maximal exertion
Increases may be step-wise, usually around 3 minute stages, so physiological parameters such as heart rate and oxygen consumption reach steady state for each level of intensity.
The test may also follow a ramp protocol, in which the intensity steadily progresses to max
The test completes when the athlete cannot maintain the work output.
What happens during a GXT?
As the intensity increases, the rate of ATP consumed by muscular contraction exceeds the rate it can be replenished by aerobic respiration
The deficit is met by substrate level phosphorylation, during anaerobic glycolysis
Lactate is produced and protons (H+) accumulate in the blood, lowering pH.
Acidity is regulated by bicarbonate buffering – HCO3- ions released from the red blood cell cytosol into the plasma reacts with the H+ ions forming H2O and CO2 to maintain a stable blood pH
The excess carbon dioxide augments an increase in ventilation.
The oxygen consumption continues to increase in a linear
fashion to the increase in intensity until V! max
What happens if you plot Co2 production and O2 consumption during a GXT?
lot best fit lines through two clear gradients. The first line will have a gradient slightly less than 1, while the second slightly greater. The intercept of the two lines is a ‘threshold’ point which represents the effect of increased acidosis.
Activity levels below and above this threshold are often categorised as light to moderate and severe respectively.
Since the deflection point in CO2 production reflects the acidosis associated with lactate production, it serves as an indirect method for measuring the lactate threshold.
Like the lactate threshold, the ventilatory threshold may be used to determine relative intensity
If an individual exercises at 80% of their VT, or gas exchange threshold, their exercise intensity is ?
moderate
Likewise, at 30% of the difference between VT and maximal intensity (during a ramp test), the intensity will be heavy.
This is sometimes called 30 Delta, for those researchers who classify intensity using the Delta concept.
Describe maximal oxygen uptake?
The maximum ability to take in, transport, and utilise oxygen during exercise
he gold standard aerobic fitness test, used extensively in the assessment of athletes and research.
The criteria used to ensure the test is a true reflection of maximum effort include: Achievement of ‘plateau’ of oxygen consumption (e.g. < 150
ml.min-1 increase in V! for a > 25 W increment in power output); RER > 1.10; Heart rate ± 10 beats above O2
predicted maximum; RPE > 17 (Borg 6-20 scale). Two of these criteria is sufficient to accept the test results, and can be reinforced by subjective assessment of the athlete.
