Week 7 Flashcards
Why do we care about VO2max?
- Predicts performance
- Within elite athletes where VO2max is very high other variables determine performance
o But high VO2max is required to be an elite athlete
LT1 work rate and HR
250 W
140 bpm
LT2 work rate and HR
305 W
151 bpm
CP work rate and HR
385 W
170 bpm
Zone 1 work rate and HR
HR=<120bpm, WR= <175W
Zone 2 work rate and HR
120-140bpm, WR= 175-250 W
Zone 3 work rate and HR
HR= 140-151 bpm, WR= 250-305 W
Zone 4 work rate and HR
HR= 151-170bpm, WR=305-385 W
Zone 5 work rate and HR
HR= > 170bpm, WR= >385 W
What is LT1?
Upper limit of moderate intensity domain
Blood lactate typically rises to 2.0mmol/L
What is LT2?
Onset of blood lactate accumulation (OBLA)
Closely associated with CP
Blood lactate levels rise to 4.0 mmol/L
How can you estimate LT1?
-MOD- monoexponential (constant O2 consumption per work rate (W) (efficiency))
-HVY- slow component
-SVR- no steady state
When does the slow component occur?
During heavy and severe constant load exercise
Starts later in exercise (time delay of about 120-180 seconds)
How does the slow component work?
- The slow component of VO2 represents an increased O2 cost of locomotion when exercise is performed more than 3 min at a constant workload above LT
- When exercise is performed btwn LT and CP (heavy), the slow component reaches steady state
- When effort rises above CP (severe) a steady state is not achievable
What is the emergence of the slow component in the heavy intensity domain due to?
Metabolic shift bwtn aerobic and anaerobic systems
How can we use the slow component to identify the HVY intensity domain?
It is where there is an additional increase in O2 cost/consumption
What happens to the slow component as intensity increases?
The magnitude of the slow component increases the further above LT1 you get
During what type of protocol are diff VO2 responses not visible?
Incremental/ramp protocols
What happens to the slow component during constant load exercise?
Slow component is visible during HVY and steady state is not achieved during SVR
Purpose of the Fatmax test
Incremental step test designed to assess maximal fat oxidation (MFO) rate and the intensity at MFO (Fatmax) using indirect calorimetry
Why was the Fatmax test developed?
To define the relationship between whole-body fat
oxidation rates and exercise intensity
What does the Fatmax tell us?
Allows us to estimate the maximal rates of fat oxidation and therefore allows us to see where the slow component starts to estimate LT1
VO2 and VCO2 are used to estimate substrate utilization and MFO (g/min)
Test can be used to determine LT1 and CP
What would ideal data look like from the Fatmax test?
Increasing intensity and increasing fat oxidation up until a point at which carb oxidation takes over and fat oxidation decreases
Duration of steps in Fatmax test
6 min to ensure steady state is reached
What else does the Fatmax test protocol allow us to examine?
VO2/WR
VCO2/VO2
VE/VO2
RER/VO2
Can be then used to estimate LT and CP