Creado por Cheyann Newman
hace alrededor de 7 años
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Pregunta | Respuesta |
At low exercise intensities ATP regeneration is primarily from what? What happens as exercise intensity increases during an incremental test? | - Primarily from aerobic metabolism once a steady state it reached - The relative contribution of anaerobic metabolism becomes greater |
What causes lactate threshold and ventilatory threshold? What is a lactate/ventilatory threshold? | - The accelerated anaerobic metabolism at higher intensities of exercise - An identifiable intensity of exercise during an incremental test where there is a disproportionate increase in blood lactate above resting levels, and a corresponding disproportionate rise in ventilation. |
Where does the disproportionate change in blood lactate or ventilation occur? | - Near the intensity of exercise called Anaerobic threshold |
Define anaerobic threshold? Can anaerobic threshold be accurately identified during an incremental test? | - The highest intensity for which measurement of VO2 accounts for all of the energy required for sustaining that intensity of exercise - No. But several markers can be used as indicators that the subject is close to their anaerobic threshold |
What happens above anaerobic threshold? and what does it cause? | - Some contribution to the continuing energy requirement by anaerobic metabolism - results in accumulation of lactate in the blood when that intensity of exercise is continued for several minutes |
What are the two apparent thresholds in using ventilatory and blood lactate parameters during incremental exercise ? | - The first threshold is called aerobic threshold. The second threshold is called anaerobic threshold |
What is the first threshold associated with? | - The first non-linear increase in VE and the first sustained increase in blood lactate concentration above resting lvl. (these physiological changes usually occur at blood lactate of 2.0 - 2.5 mmolxL^-1) |
What happens between the first and second ventilatory thresholds? | - Excess acid released from glycolysis is buffered by CO2 release during ventilation |
What is the second threshold associated with? | - Blood lactate concentrations of approximately 4.0mmolxL^-1 (usually lactate change because ventilation changes) |
It can be difficult to identify the intensity of exercise associated with the two lactate thresholds - so which one is identified? - How is it sometimes identified by? | - Second threshold - Identify the intensity of exercise associated with 4mM blood lactate |
What is a critical intensity for identifying training zones? | - Intensity of exercise at Anaerobic threshold when expressed as a % VO2max |
1) How long can an athlete continue an exercise for above the anaerobic threshold? 2) Below this intensity how long is the duration? 3) What can specific training methods do to anaerobic threshold ? 4) Where may AnT occur at percentage wise for VO2max? What about for trained individuals? | 1) Less than 40 mins 2) Very long 3) AnT can be increased to a greater % VO2max 4) 50-70%. May not occur until greater than 85% of VO2max |
What are two things in addition to expressing AnT as a percentage of VO2max would be useful for athletes to customize their training sessions? | - Heart rate, power output and/or speed associated with the determined anaerobic threshold |
What are the 4 types of methods used to determine lactate or ventilatory thresholds? | 1) VE vs. Power Output (watts) 2) VE vs VCO2 3) FECO2 4) Blood lactate determination (LT1 and LT2) |
METHOD 1: VE vs Power Output |
- Plot VE as a function of Power Output
- The 1st nonlinear increase in VE represents VT1 (about 40-60% VO2max)
- The 2nd nonlinear increase in VE represents VT2 (about 65-90% VO2max)
- The corresponding VO2 be expressed as a % VO2max
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METHOD 2: VE vs VCO2 (aka v-slope method) |
- Beginning of incremental exercise VE vs. VCO2 increases linearly
- As subject approaches maximal levels of exercise there becomes a non-linear inflection (associated with a specific value for VCO2)
- The equivalent VO2 is als determined to calculate %VO2max
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METHOD 3: FECO2 |
- As exercise intensity increases there is a continuous increase in VE and a continuous rise in VCO2
- However, there is a point where hyperventilation exceeds the ventilation needed to rid the body of metabolically produced CO2 and there is a marked DECREASE in FECO2
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METHOD 4: Blood Lactate Determination |
- LT1: power output associated with a blood lactate concentration of 2-2.5 mM
- LT2: power output and heart rate associated with blood lactate concentration of 4.0 mM
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Respiratory Exchange Ratio and Ration of Perceived Exertion (not a method. it is a guideline) | - RER of about 0.92 - 0.94 at LT1 - RER of about 0.98 - 1.02 at LT2 Rating of perceived exertion at LT2 should be about 14 on the Borg Scale |
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