Lecture 2 - Effect of Protein on Endurance Exercise Flashcards
What are proteins?
- Chain (polymer) amino acids
- Arranged into primary, secondary and tertiary structures (quaternary - not essential)
- Contains nitrogen - unlike CHO and lipids
How are proteins made?
- Transcription
- Translation (initiation, elongation, termination)
- Post-tranlation modification
All of the above made up the term ‘protein synthesis’
Name 3 classifications of amino acids and 1 example of each
- Indispensable/essential - Valine
- Conditionally indispensable/essential - Glycine
- Dispensable/non-essential - Alamine
What makes proteins different form CHO and Lipids?
Contains nitrogen
2 ways we can measure protein in the body
- Nitrogen Balance
2. Stable Isotopes
Explain how nitrogen balance works and pros/cons
- Nitrogen excretion = nitrogen intake
99% of nitrogen in the body comes from protein, therefore measuring nitrogen is a good indication of protein
Pros: When using large groups of people, it gives accurate representation
Cons: - Full control of diet needed
- Need to know everything being excreted/sweated
- Hard to measure
- Not precise on an individual basis
Explain stable isotopes and it’s pros and cons
Administration of an element that is functionally identical but distinct from a protein, so we can tract and measure it
Transported from plasma to intracellular pool, some is oxidised, some degraded and some synthesised
Pros:
- Works on an individual basis with an athlete
- Can look at an individual meal rather than whole diet - allowing us to give advise on protein ingestion
Cons:
- Very labour intensive - study someone under a laboratory condition
How much protein do we turnover?
Skeletal muscle turnover rate:
- 1-2% per day
Muscle protein synthesis rates:
- 0.04% - 0.14% per hour
Can protein help to maintain muscle mass when endurance exercise is used for weight-loss?
- Weight loss is generally considered to happen across the spectrum
- Lean muscle mass is conserved with increased protein intake
How much protein is advised to optimise post exercise muscle reconditioning?
20-25g
What happens at the transamination phase?
Changing amine group to another amino acid to clear the nitrogen
What does endurance training do to myofibril/mitochondrial protein synthesis rates? (Wilkinson et al, 2008)
Endurance training increases mitochondrial protein synthesis rates, not myofibril
How does protein feeding during recovery effect myofibril/mitochondrial protein synthesis rates? (Green et al, 2011)
Protein feeding increases myofibril but no mitochondrial protein synthesis rates
How does endurance performance in the fasted state, alter net protein balance?
Endurance in the fasted state generates a negative net protein balance
What does protein ingestion before, during or after endurance exercise do to net protein balance?
Promotes positive net protein balance, due to increased muscle protein synthesis
