Protein Metabolism + Nutrition in Endurance Performance

Question 1

Define protein

Answer 1

chains of amino acids, arranged into primary, secondary and tertiary structures which contain nitrogen.

Question 2

What are the 3 processes of protein production

Answer 2

transcription, translation (initiation, elongation and termination) and post-translation modification

Question 3

Give 3 functions of proteins

Answer 3

• Provide structure
• Hormones
• Antibodies
• Transporters
• Enzymes
• Movement

Question 4

Define Muscle) protein synthesis

Answer 4

o The creation of new proteins from amino acids (as a result of initial transcription of the DNA).

Question 5

Define Muscle) protein breakdown

Answer 5

o The degradation of whole proteins back to constituent amino acids.

Question 6

Define (Muscle) protein balance

Answer 6

o The net result of muscle protein synthesis and muscle protein breakdown (Synthesis-Breakdown).

Question 7

Define Amino acid oxidation

Answer 7

o The breakdown of intracellular amino acids for energy production.

Question 8

Define Amino acid uptake

Answer 8

o The rate of transport of amino acids from one pool (e.g. the plasma) to another (e.g. the muscle cell).

Question 9

Define Amino acid utilization

Answer 9

o The amount of dietary amino acids (obtained from dietary protein) that is used by the tissue and organs of the body for the above processes.

Question 10

What are the 3 possible classes of proteins

Answer 10

Essential
Non-essential
Conditionally essential

Question 11

Define primary structure of protein

Answer 11

Sequence of amino acids

Question 12

Define secondary structure of protein

Answer 12

Local folding of polypeptide chain

Question 13

Define tertiary structure of protein

Answer 13

three dimensional folding pattern of a protein- side chain interactions

Question 14

Define quaternary protein structure

Answer 14

protein consisting of more than one amino acid chain

Question 15

What is deamination

Answer 15

removal of amine group (NH3) in liver

Question 16

In the average person,how much protein is synthesised each day?

Answer 16

350g/day

Question 17

In the average person, what is the protein synthesis rate?

Answer 17

1-2% a day

Question 18

What is a stable isotope

Answer 18

Isotopes function identically, but can be marked, so act as a tracer to measure net nitrogen balance.

Question 19

give 3 factors affecting protein turnover

Answer 19

• Habitual diet
• Protein intake
• Energy intake
• Hormones
  o Insulin
  o Steroids e.g. testosterone
• Exercise

Question 20

Give 3 potential roles of dietary protein in sport and exercise

Answer 20

	Muscle hypertrophy 
	Muscle strength 
	Immune function 
	Central fatigue
	Glycogen re-synthesis
	Additional energy during exercise 
	Specific function of individual amino acids 
	Effects on muscle damage

Question 21

Bowtell et al 1998 found that leucine oxidation increased most when after exercise

Answer 21

1 hour post-exercise

Question 22

Hulston et al 2011 found what sort of protein balance during exercise

Answer 22

negative net balance, but exercise increased both protein synthesis and breakdown

Question 23

Protein ingestion before, during or after exercise promotes what sort of balance

Answer 23

positive net balance

Question 24

Protein ingestion is associated with which synthesis rates?
A) increased myofibrillar
B) decreased myofibrillar
C) Increased mitochondrial
D) decreased mitochondrial

Answer 24

A) increased myofibrillar

Question 25

In the trans-alp challenge, which group improved their performance? o 7.6% cho-e solution and cho bars (placebo) o 7.2% cho-e, 1.8% wp solution and cho/protein bars.

Answer 25

o 7.2% cho-e, 1.8% wp solution and cho/protein bars.

Question 26

What is central fatigue theory

Answer 26

Fatigue may be associated with inadequate central nervous system “drive” to the working muscle e.g. by neurotransmitters

Question 27

What is the serotonin central fatigue theory

Answer 27

Increased brain 5-hydroxytryptamine (5-HT) (Serotonin) concentration causes a deterioration in performance

Question 28

Describe the central fatigue theory mechanism

Answer 28

``` the selective transporter poses competition with branched chain amino acids (increasing tryptophan and serotonin) so... • reduced [BCAA] and increased [fTryp] • increased fTryp : BCAA • increased fTryp transport into brain • increased serotonin synthesis • impaired CNS function ```

Question 29

Did Blomstrand et al 1991 show BCAA supplementation to improve mental and physical performance

Answer 29

* some evidence of improved mental performance | * slower runners (3.05 - 3.30 h) improved performance

Question 30

Did Van Hall et al 1995 show BCAA/tryptophan supplementation improved physical performance

Answer 30

• No difference in time to exhaustion despite increased fTryptophan:BCAA.

Question 31

True or false: A hypocaloric diet decreases body mass, lean body mass and fat mass

Answer 31

False, Lean body mass increased

Question 32

What is the recommended protein dose?

Answer 32

RDI = 1.2 – 2.0 g/kg

Question 33

What is the timing consideration for protein ingestion?

Answer 33

o Protein ingestion in close proximity to exercise may facilitate muscle reconditioning o Protein feeding during exercise does not appear to enhance exercise performance assuming adequate CHO is consumed.

Question 34

True of False: Tarnopolsky et al 1992 suggested a RDA for sedentary subjects to be 0.89 g/kg/day and 1.76g/kg/day for strength trained subjects.

Answer 34

True

Question 35

What is the anabolic stimulus for muscle production in the diet?

Answer 35

Protein

Question 36

Why does exercise cause an immediate reduction in muscle protein synthesis?

Answer 36

the priority is ATP for muscular contraction at the time

Question 37

What is more important in Rex training: intensity or carrying it out to failure

Answer 37

carrying it out to failure

Question 38

What is more important in Rex training: eccentric or concentric exercise

Answer 38

eccentric

Question 39

Why do we see an increase in MPB following exercise

Answer 39

protein breakdown replaces protein fibres with stronger, faster fibres

Question 40

If protein turnover is around 300-600g per day.. what can this increase too post-exercise

Answer 40

around 600-900g per day

Question 41

True or false: there is a golden 30 mins post-exercise

Answer 41

False- protein synthesis is increased for up to 2 hours post. Plus, the body is sensitive to protein for all meals within this 2 days

Question 42

What does net protein accretion result in

Answer 42

Hypertrophy

Question 43

When should whey protein be ingested

Answer 43

ingested and absorbed faster than casein- so post-exercise

Question 44

When should casein protein be ingested

Answer 44

pre-bed

Question 45

What is leucine better at than other amino acids?

Answer 45

Faster FSR

Question 46

True or false: CHO can improve MPS

Answer 46

There was an increase in MPB with CHO and exercise, but CHO reduced MPS with exercise

Question 47

What is the RDA for protein? Sedentary

Answer 47

0.89 g/kg/d

Question 48

What is the RDA for protein? ReX trained

Answer 48

1.76 g/kg/d

Question 49

How much protein post-exercise will induce an optimal anabolic response

Answer 49

20-30g