Limits to exercise tolerance 1

Question 1

What is fatigue?

Answer 1

The inability to maintain power output or force during repeated muscle contractions

Question 2

Which test could be done to assess exercise performance?

Answer 2

VO2max or VO2peak

Question 3

Which test could be done to assess exercise capacity?

Answer 3

Time to exhaustion

Question 4

What are the three exercise intensity domains?

Answer 4

Moderate, heavy, severe

Question 5

What level of exertion is moderate?

Answer 5

Anything below lactate threshold/gaseous exchange threshold

Question 6

When is lactate threshold reached?

Answer 6

When the production of lactate is occuring at a faster rate to the removal rate

Question 7

What intensity of exercise is heavy?

Answer 7

Between lactate threshold and critical power/critical speed

Question 8

What intensity exercise is severe?

Answer 8

Anything above critical power/critical speed

Question 9

How is critical power tested?

Answer 9

VO2max test, record highest power output (wattage) from that. Then have them do several time to exhaustion tests with the resistance of the bike being different %s (500, 100, 50 etc) of their VO2max test. Measure the time they can go until exhausiton against these different %s. Can plot a curve which will flatten (after going down). Flattened curve is intensity that the person can maintain for a long period of time

Question 10

What are the likely fatigue mechanisms for moderate exercise?

Answer 10

Hyperthermia, mental fatigue and muscle damage

Question 11

What are the likely fatigue mechanisms for heavy exercise?

Answer 11

Glycogen depletion and hyperthermia

Question 12

What are the likely fatigue mechanisms for severe exercise?

Answer 12

Depletion of finite energy stores (W’)

Question 13

Which three elements dictate performance velocity or power?

Answer 13

Performance VO2, Performance O2 deficit, Gross mechanical efficiency

Question 14

What can limit performance VO2?

Answer 14

Lactate threshold

Question 15

What can limit lactate threshold directly?

Answer 15

Maximal oxygen consumption, aerobic enzyme activity, distribution of power output

Question 16

What can limit maximal oxygen consumption directly?

Answer 16

Muscle capillary density, stroke volume, max heart rate, hemoglobin content

Question 17

What directly influences performance O2 deficit?

Answer 17

Total buffering capacity and distribution of power output

Question 18

What is total buffering capacity?

Answer 18

How good our muscles are at buffering acidosis

Question 19

What is acidosis?

Answer 19

Acid build up in the muscles as a result of exercise

Question 20

What can affect performance O2 deficit and performance VO2?

Answer 20

Distribution of power output

Question 21

How can total buffering capacity be changed?

Answer 21

Training status and nutrition

Question 22

Which compound can improve total buffering capacity during exercise?

Answer 22

Sodium bicarbonate

Question 23

Why can taking sodium bicarbonate help with high intensity exercise?

Answer 23

It can help with buffering of acidosis

Question 24

What can influence gross mechanical efficiency?

Answer 24

% slow twitch (type I) muscle fibres, anthropometry and elasticity

Question 25

Which type of muscle fibre is more efficient?

Answer 25

Slow twitch (type I)

Question 26

If two athletes were the same height but one had longer legs, which one would be more efficient?

Answer 26

One with longer legs

Question 27

Is it better to have stiffer or more relaxed tendons?

Answer 27

Stiffer as energy can be transferred more efficiently

Question 28

Which type of athlete has the highest VO2max?

Answer 28

Endurance

Question 29

What sports do “endurance athletes do?

Answer 29

Cross country skiing, running

Question 30

Why do cross country skiers have a higher VO2 max than marathon runners?

Answer 30

They use both their arms and their legs

Question 31

Highest every VO2max?

Answer 31

93-95mL/kg/min

Question 32

Which type of marathon does VO2max correlate best with?

Answer 32

It correlated with normal marathon better than ultra marathon

Question 33

Why does VO2max correlate better with a normal marathon than an ultramarathon?

Answer 33

Ultramarathons have a slower pace and so are less reliant on VO2 for performance

Question 34

How does VO2max correlate with health?

Answer 34

It declines as you get older

Question 35

What age related issues can VO2max be used to predict?

Answer 35

Mortality and post surgery outcomes

Question 36

What is the Fick equation?

Answer 36

VO2 = Q (a-v O2diff)
Q is cardiac output
a-v O2diff is the muscle O2 extraction

Question 37

How is cardiac output measured?

Answer 37

Stroke volume * heart rate

Question 38

What is a-v O2diff in the fick equation?

Answer 38

The amount of oxygen in the artery going to the muscle minus the amount of oxygen in the vein leaving the muscle–> bigger means muscle is extracting more O2 from the blood

Question 39

In what ways can the a-v O2diff be limited?

Answer 39

Either a limitation in the limitation in the delivery of the oxygen to the muscle, or a limitation in the muscle itself and its ability to extract oxygen

Question 40

How is muscle VO2 measured?

Answer 40

Catheters are inserted into different blood vessels in the body.

Question 41

What are the main key steps in O2 transport?

Answer 41

Lungs, respiratory muscles, heart, muscle, mitochondria