week 8 Flashcards
(22 cards)
Athlete integrated support team (IST)
athlete(s) and coaching staff!!!!
therapy: athletic trainer, physiotherapist, massage therapist, chiropractor
medicine:
sports science: physiologist, biomechanist, performance analyst.
strength and conditioning
mental performance: sports medicine physician, surgeons
nutrition: dietician
others: vision, podiatry..
what are the principal determinants of the fraction of VO2max that is sustainable for a given duration?
power= VO2max x %VO2max x efficiency
velocity= VO2max x %VO2max x economy
when the highest values for VO2max and economy are used… a — marathon is possible
sub 2 hour.
but the combination is rare– there may be a tradeoff
3 phases of oxygen kinetics
Phase 1: cardiodynamic component. abrupt increase in VO2 due to blood returning from increased venous return
Phase 2: primary (fast) component. reflects kinetics of O2 uptake
Phase 3: steady state (slow component), only at higher intensities ex. the heavy domain
features of the slow component (phase 3 oxygen kinetics)
- it is the continued rise of VO2 beyond primary phase (2) above the anticipated steady state
-occurs during heavy intensity domain >LT or above
- it reduces efficiency/economy
-reduces %VO2 max that can be sustained due to increased substrate depletion
what is the slow component hypothesis
(bc it is not yet fully understood)
a) loss of efficiency in a working muscle= reduces free energy of ATP
–> need more ATP for a given task demand and need more O2 for oxidative phosphorylation
b) recruiting additional higher-threshold motor units w less metabolically efficient muscle fibres
c) [PCr] has slow component-like response in the heavy exercise domain. role in meeting demand anaerobically prior to steady state
2 ways that VO2 kinetics contribute to exercise tolerance
1) anaerobic energy is used when VO2 kinetics are catching up (O2 deficit)
2) slow component reduces efficiency, increased CHO catabolism and heat
what determines thresholds?
muscle metabolism, blood acid-base status and ventilation during exercise
Threshold and VO2 kinetics:
1st threshold
slow component emerges. progress to steady state
Threshold and VO2 kinetics:
2nd threshold
VO2 max achieved (no steady state)
blood lactate thresholds
1st= lactate threshold
2nd= maximal lactate steady state
gas exchange, ventilation thresholds
1st= gas exchange threshold or first ventilatory threshold
2nd= respiratory compensation point or second ventilatory threshold
field test thresholds
1st= talk test
2nd= talk test, critical power/critical velocity
%VO2 max healthy thresholds
1st= 50-65
2nd= 70-80
%VO2 max highly trained
1st= 70-80
2nd= 80-90
threshold=
breakpoint at which a physiological variable occurs
ex. gas exchange threshold has a upward trend of VCO2 vs VO2
blood lactate first threshold characteristics
“lactate threshold”
=stage at which lactate increases by 1 mmol/L over rest during graded exercise test
blood lactate second threshold characteristics
“maximal lactate steady state”
= highest power at which steady state in blood lactate levels achieved in a series of constant load tests
Critical power
=maximal power output at which metabolic homeostasis (steady state) is sustained
ex. VO2, PCr, and lactate levels
The critical velocity test: velocity-duration relationship
series of timed work bouts to failure at diff workloads provides a field-based estimate of the 2nd metabolic threshold
critical power test and blood volume changes
plasma transfusion= can sustain power for longer so increased critical power
blood donation= hit max O2 uptake sooner so decreased critical power
Do O2 kinetics change when donating blood?
No!!!!
VO2 and power output changes but O2 uptake kinetics doesn’t change
