1
What is VO2max?
- maximal O2 uptake (uptake doesn’t goes up with increase of exercise)
- best single measurement of aerobic fitness
2
Relative VO2max.
- associated with lean mass + different body sizes (most
accurate)
- your weight (L) per minute(min) per kilogram of body weight(kg)
3
Absolute VO2max.
-
The amount of oxygen you breathe in liters per
minute.
- depends on your age, weight, height, and gender.
- easy standard measurements
4
What is the lactate threshold?
- the point at which, during incremental exercise,
lactate builds up in the blood stream at a level
that is higher than resting values
- hydrogen ion increase = pH dropping
- high use of CHO // low use of fat
5
Lactate threshold between train/untrained?
- Untrained: 50-60% ov VO2 max (upperside)
- Trained: 55-70% of VO2 max
6
What are the causes? (lactate threshold)
- Pyruvate accumulation ==> lactate
- Glycolysis: carbohydrates is cionvered to pyruvate but converted to lactate if Krebs cycle is too backed up/pyruvate production=too high
7
What is the metabolic fate of lactate produced in the body?
- pyruvate accumulation → lactate
- oxidation + glycogen synthesis (gluconeogenesis)
8
Describe postexercise O2 consumption.
O2 demand
- > O2 consumed in early exercise
9
Describe postexercise O2 consumption.
O2 consumed
- >O2 demand in early recovery
10
How can one measure anaerobic capacity noninvasively?
- wingate anaerobic test / critical power test
11
What is the ventilatory threshold?
when ventilation increases at faster rate than VO2
12
Describe why exercise economy is important to importance?
- Important: to have the ability to use less energy for better performance
- Increase with skill as energy is needed less
13
Is one’s exercise economy the same for all activities (swimming vs. running)
- Varies with each type of sport (multifactorial)
14
What are the main causes of fatigue?
- Energy systems (substrate depletion // PCR, glucose)
- Metabolic byproducts (H+ accumulation)
- Failure of muscle contraction (M. fibers) // Neural fatigue
15
- What are the main causes of fatigue?
- Energy systems (substrate depletion // PCR, glucose)
- PCR: deplete faster than ATP(depletion = decrease rate of muscle contraction),@ short term+high intensity
- Glycogen depletion: limited+deplete fast // increase fat use (spare glycogen)
16
- What are the main causes of fatigue?
- Metabolic byproducts (H+ accumulation)
- Metabolic byproducts (H+ accumulation)
- Heat alters metabolic rate (hot= tire quickly, cold= tire slowly)
- lactic acid dissociates (low muscle pH = acidosis)
17
- What are the main causes of fatigue?
- Failure of muscle contraction (M. fibers) // Neural fatigue
- fail @ neuromuscular junction = can’t activate muscle
- decrease ACh synthesis + release
- alt ACh breakdown @synapes
- increase muscle stim threshold (K+)
- inhibit Ca2+ release from SR