Nutrition SDL #2: Sports Nutrition Flashcards
What % of weight does muscle account for in athletes?
40-50%
What do slow twitch fibers use for energy?
FAs and glucose in blood through oxidative phosphorylation
What do fast twitch fibers use for energy? Is this efficient?
Glycogen, not efficient because anaerobic breakdown uses only 6% of the energy potential of glycogen because going so fast
Describe the order in which energy is used in muscles.
- ATP stores (run out in 2-3 sec)
- Creatine phosphate (lasts 10 seconds)
- Fuel metabolism (glycogen or fat)
What does creatine phosphate do to recharge energy supplies?
Transferring its phosphate to ADP
How does FA oxidation vary in slow twitch muscles during different levels of effort?
Stays constant
What is the main source of energy for muscles at rest or during light to moderate exercise?
Fat
When is glucose used in slow-twitch muscles instead of fat?
When the energy demands exceed 300-400 kcal/hr
What large molecule does FA beta oxidation require to proceed? Why?
Glucose: provides intermediates for Krebs cycle
How long does it take for glycogen stores in a muscle to be depleted?
Hours
How many calories are provided by 1 g of fat?
9 kcal
What is the most high density energy source?
Fat
What are the 7 cofactors necessary for beta oxidation of fats and glycolysis?
- Thiamin: B1
- Riboflavin: B2
- Niacin
- Pantothenate
- Biotin
- Iron
- Magnesium
What kind of patients may lack enough iron?
Young women and vegetarians
What are fats converted to in beta oxidation?
Acetyl CoA
How many calories are provided by 1 g of glucose?
4 kcal