Carbohydrate ingestion to replace muscle glycogen Flashcards
what relationship is seen between:
Pre-exercise muscle glycogen content and exercise capacity
Amount of CHO in diet and pre-exercise muscle glycogen content
higher muscle glycogen = better exercise capacity
higher CHO intake = higher muscle glycogen
higher CHO intake between training has been shown to maintain muscle glycogen at almost maximal levels of glycogen, whereas low CHO sees a gradual depletion
explain the concept of glycogen super-compensation
depletion of muscle glycogen via exercise allows a greater level of muscle glycogen to be achieved during recovery
glycogen content rises above normal levels
explain why a mod/high carb intake stratergy in the days before competition is preferred to a high/high stratergy
no difference in final muscle glycogen levels
but mod/high would be easier for athlete to consume/stick to
describe the evidence which shows a one day protocol is suficient to allow optimal enhancement of glycogen stores
when consuming 10g/kg/day
muscle glycogen content doubled in first 24 hours
was then no significant increase over the next few days
describe evidence which shows the benefit of high CHO diet in relation to performance in team sports
high or low carb diet consumed in the 3 days between midweek and weekend match
at 2nd match, high carb group had:
higher muscle glycogen at start and half time
slightly higher at end
significantly more distance covered in 2nd half
less walking distance
more sprinting distance
is it better to consume CHO before or during exercise
no difference in 30km TT performance
before = higher before, drops off at start and stays constant during
during = lower before, same as before group at race start and then higher during the race
Is there a risk of hypoglycaemia associated with pre-exercise feeding
placebo drinks had higher blood glucose than glucose drinks at the start of a race
but during the race there was no difference in blood glucose levels
what are the recommended daily intakes of CHO associated with difference levels of training
light = 3-5 g/kg/day
moderate = 5-7 g/kg/day
high = 6-10 g/kg/day
very high = 8-12 g/kg/day
How does the timing of CHO intake alter the rate of muscle glycogen storeage
delayed intake = slower rate of muscle glycogen store age immediately after exercise
no difference in the rate at 2-4hrs, when both groups had eaten
total glycogen storage higher in those who ate immediately bc had been synthesizing at a greater rate immediately post exercise
what level of CHO intake is required for optimal rates of glycogen synthesis
1-1.2 g/kg/hr post exercise for 2-4 hours
or 10g/kg/day for general
does addition of protein to meals aid glycogen storeage
carb vs carb + protein vs double carb
carb + protein saw biggest increase in plasma insulin levels
also saw a significant increase in glycogen synthesis rate, similar level of increase seen with double carb
however, easier to consume carb + protein rather than double carb
what relationship is seen between muscle glycogen level during training and AMPK response
what is the possible significance of this
lower muscle glycogen during training = greater AMPK activity as a response
possible mechanism for a better adaptation to training
describe the results seen in trails of train low, compete high stratergies
saw greater power outputs
greater tie to exhaustion
greater total work done
greater activity of citrate synthase or haloacid dehydrogenase (key for oxidative metabolism)
reduced self selected training intensity
increased risk of injury with low muscle glycogen
greater risk of infection with low CHO intake
in which proteins was there a greater increase seen when sleeping in a fasted state post exercise
PDK 4
AMPK
p38 MAPK
P-ACC
From the reading, what level of CHO intake is required for:
sports lasting >1 hour
sports lasting >2.5 hours
30-60g/hour
90g/hour
