Week 8 Flashcards
Findings of single leg bike studies
No matter what dosage of protein, exercise stimulus was always larger in single leg studies. No further increase in protein synthesis when add more protein beyond 20 grams of protein. In response to 40 grams of high quality phenylalanine oxidation was much higher
If protein consumed is not going into the formation of other protein it must be going elsewhere
At around 0.34 g/kg of body weight is where protein synthesis plateaus relating to myofibrillar fsr.
Around 0.3 g/kg of body can be enough to optimize muscle protein synthesis
You only need the essential amino acids to increase muscle protein synthesis and so can remove all non-essential aa’s and have same metabolic effect.
Comparing animal protein sources with soy protein sources
Animal protein sources found to have greater 3 hour recovery than soy and cause greater lean mass. Animal proteins have more essential amino acids.
Milk protein = 20% whey and 80% casein
What is whey?
Whey is a fast digesting protein. Made of diam and tripeptide chains and are broken down easier in the splanchic area of the gut than casein so is in the circulation faster than casein does.
Peptide chains in casein = complex - they coagulate in the acidic environment in the stomach and so have a slower release into the stomach.
Some evidence suggests the faster the rate essential amino acids arrive into circulation the greater the rate of protein synthesis.
There is 2 parameters with ingested protein that control muscle anabolic responses?
Essential amino acids and absorption rate.
Whey protein includes more essential amino acids gram for gram than other animal proteins like casein or plant based proteins like soy.
Why is whey enriched in essential amino acids?
It is due to the leucine fraction of milk.
Beta lacto globulin and alpha lactalabumin = fractions of why proteins that contain very high leucine- leucine = very important for protein synthesis and stimulates more anabolism. You can provide more soy or casein to get the same amount of leucine but on a dose for dose response whey is thought to be best to provide protein synthesis.
What can slow proteins be used for?
Used to remodel before you sleep. If you consume large dose of slow release protein before bed can have an overall positive protein balance
There was increased muscle fibre protein size found in overnight protein group versus the control group.
There is an effect of prior resistance training on muscle protein for atleast 24 hours after exercise maybe even 48 hours.
Areta et al found it is also about frequency of dosage as well as amount with higher protein synthesis in group who consumed 4 x 20 g versus group who consumed 2 x 40 g.- greatest muscle anabolism in 4.
Is it possible to lose fat and gain lean tissue mass?
Yes. Though often a third of mass lost is lean muscle mass so this can compromise performance.
In energy deficiency study in carb and protein group lean and fat mass was lost.
However in protein group optimise the ratio of lean to fat mass lost- so carb group lost less lean muscle tissue.
Energy restrictions can influence muscle protein turnover.
Effects of moderate to high energy deficiency condition
High energy deficiency causes a large decrease in muscle protein synthesis.
Energy deficiency because of exercise seems to better maintain muscle protein synthesis compared to energy deficiency due too only caloric intake.- and due to caloric intake sees a large decrease in energy efficiency.
What happens if reduced caloric intake by 40%.
Lower protein group lost more weight though they lost more lean mass whereas higher protein group were better able to maintain lean mass.
Combo study of HIIT , resistance training, plyo and cyce tt
2 conditions = high protein and lower protein groups.
Both groups lost similar mass but higher protein group actually gained lean mass.
Training 6 times a week is probably enough to maintain protein synthesis.
Higher protein group also got improved cycle tt.
Fast vs slow weight loss
Fast weight loss worse able to maintain lean mass than slow weight loss- with protein content less able to maintain muscle mass than in slow.
Supplementing dairy products can help maintain high quality weight loss.
Muscle protein turnover rate?
1-2% a day. Maximizing training adaptations should have around 1.6- 2g /kg per day. Loss of lean tissue mass during energy restriction may be due to decreased protein synthesis.
