Metabolic Responses to Sprint Exercises

Question 1

What is a observed where performance can be measured and appropriately compared through historical time?

Answer 1

A clear and steady progression in performance.

Question 2

Define exercise intensity?

Answer 2

The rate of power production relative to the functional capacity of the individual.

Question 3

Define exercise duration?

Answer 3

The duration for which a particular exercise intensity is sustained.

Question 4

Give the exercise intensity domains?

Answer 4

Moderate, heavy, very-heavy, severe.

Question 5

What are the characteristics of moderate intensity exercise?

Answer 5

No sustained increase in arterial blood lactate and a tolerable duration >3 hours.

Question 6

What are the characteristics of heavy intensity exercise?

Answer 6

Sustained increase in arterial blood lactate that comes to a steady state and a tolerable duration of ~1-3 hours.

Question 7

What are the characteristics of very-heavy intensity exercise?

Answer 7

Progressive increase in arterial blood lactate throughout and a tolerable duration of ~2-60 minutes.

Question 8

What are the characteristics of severe intensity exercise?

Answer 8

Rapid muscle fatigue, limited by the VO2max and a tolerable duration of

Question 9

What does heterogenous mean in terms of muscles?

Answer 9

Made of fibres with different metabolic, physical and anatomical properties.

Question 10

Which muscle fibre types are small in size?

Answer 10

Type 1

Question 11

Which muscle fibre types are large in size?

Answer 11

Type 2x

Question 12

Which muscle fibre types are highly resistant to fatigue?

Answer 12

Type 1

Question 13

Which muscle fibre types are the most power and force producing?

Answer 13

Type 2x

Question 14

Which muscle fibre types contract rapidly

Answer 14

Type 1, 2x and 2a

Question 15

Which muscle fibre type is most mitochondrial dense?

Answer 15

Type 1

Question 16

Which muscle fibre type is highly oxidative?

Answer 16

Type 1

Question 17

Which muscle fibre type is highly glycolytic?

Answer 17

Type 2x

Question 18

What is the fibre recruitment profile?

Answer 18

The orderly hierarchy of motor unit recruitment from type 1, to type 2a, to type 2x.

Question 19

Is the relationship between fibre type and metabolic properties fixed?

Answer 19

No.

Question 20

What does the relationship between fibre type and metabolic properties depend on?

Answer 20

Response to and type of training.

Question 21

In skeletal muscles what is the [ATP] 5-8mmol/kg enough for?

Answer 21

8 maximal contractions or ~2-3 seconds.

Question 22

During sprint exercise from what sources is ATP largely from?

Answer 22

Anaerobic: stored ATP, PCr breakdown and glycolysis.

Question 23

What is cross talk of energy providing pathways?

Answer 23

The contribution of energy derived from alternative pathways integrating.

Question 24

What are the relative contributions of each energy providing pathways dependent on?

Answer 24

Fibre type; type 1 has a slow decrease in [ATP] whereas type 2x has a large decrease which is protected and maintained.

Question 25

From high to low, list the storage of carbohydrates, glycogen and fatty acids?

Answer 25

Fatty acids> carbohydrates> glycogen> PCr

Question 26

What are the fastest routes to provide energy?

Answer 26

Stored ATP and PCr.

Question 27

From high to low, list the maximum flux of carbohydrates, fatty acids, glycolysis and PCr?

Answer 27

PCr> glycolysis> carbohydrates> fatty acids.

Question 28

What enzyme breaks down PCr?

Answer 28

Creatine Kinase

Question 29

What is a quality of creatine kinase?

Answer 29

It is near-equilibrium and has the fastest rate of all other enzymes in the muscle.

Question 30

What does PCr breakdown buffer?

Answer 30

ADP accumulation

Question 31

What is thought to be a major cause of muscle fatigue?

Answer 31

Inorganic Phosphate

Question 32

How was inorganic phosphate found to be a major cause of muscle fatigue?

Answer 32

Using genetically mutated mice with no creatine kinase activity; showed lower absolute force but better maintenance of force due to lack of Pi formation.

Question 33

What do high rates of ADP accumulation cause?

Answer 33

Slower rates of muscle relaxation which can dramatically inhibit muscle power.

Question 34

What is excellent at buffering ADP accumulation?

Answer 34

The Lowman reaction

Question 35

What does MR spectroscopy show sprint to contribute to?

Answer 35

And alkalosis rather than an acidosis.

Question 36

What is MMCK?

Answer 36

Mechanical machinery creatine kinase

Question 37

Where is MMCK expressed?

Answer 37

In the cytosol

Question 38

Where is mitochondrial CK co-localised to?

Answer 38

The adenine nucleotide translocase (ANT)

Question 39

What rae MMCK and MiCK required for?

Answer 39

Maintenance of the creatine-phosphorcreatine shuffle to communicate between the mitochondrial and myofibril.

Question 40

What is there close communication between in type 1 and type 2 muscle fibres?

Answer 40

Type 1: PCr and oxidative phosphorylation | Type 2: Glycoslyis and PCr

Question 41

What two types of buffers is PCr?

Answer 41

A temporal energy buffer, providing rapid ATP provision during sprint exercise when ATP storage is challenged, and a spatial energy buffer, a signalling molecule to communicate with other cellular compartments to increase the rate of ATP production.

Question 42

What two reactions buffer cytosolic [ATP] during severe intensity exercise?

Answer 42

Adenylate kinase and AMP deaminase

Question 43

What does AMP accumulation play an important role in stimulating?

Answer 43

Glycogen phosphorylase and PFK

Question 44

When is AMP deaminase inhibited?

Answer 44

When [ATP] is high

Question 45

What is IMP an allosteric activator of?

Answer 45

Glycogen phosphorylase

Question 46

What do type 2 muscle fibre have greater of?

Answer 46

[PCr], glycogen content, glycogen phosphorylase activity, AMP deaminase activity, a-glycerophosphate shuttle expression.

Question 47

Is glycolytic flux dependent on the oxygen availability in type 2 muscle fibres?

Answer 47

No, but in type 1 it is.