Option D unit D4 - Glycogen

Question 1

what is glycogen

Answer 1

Glycogen is converted to glucose in muscles for ATP generation during exercise

Question 2

Glycogen content of specific skeletal muscle fiber types:

Answer 2

• Slow twitch (type I) - low glycogen content
• Fast twitch type IIa - medium glycogen content
• Fast twitch type IIb - high glycogen content
• Low intensity exercise predominantly uses slow twitch muscle fibers = less oxygen (aerobic)
• High intensity exercise predominantly uses fast twitch/type II muscle fibers = more glycogen (anaerobic)

Question 3

carb digestion

Answer 3

• Glycogen is stored glucose (carbs). Different foods have different rates of carb digestion.
• Glucose is released at different speeds from food we eat.
• Glycemic Index (GI) : the ranking system for carbohydrates based on how quickly the glucose (sugar) enters the bloodstream after digestion
  –> High glycemic index = will enter the bloodstream faster and all at once
  –> Low glycemic index = enters the bloodstream slow and over time
  Does not depend on how much glucose Ex. 10 grams of glucose
  High = all 10 grams enter the bloodstream fast and at once
  Low = 2 grams enters the bloodstream slowly → takes longer for all 10 grams to enter the blow stream.

Question 3

The relevance of GI with regard to carbohydrate consumption by athletes pre- and post competition:

Answer 3

• consuming foods containing carbohydrates before and after exercise may be beneficial in aerobic performance and recovery
• Key is when do you want the glucose to impact the body
  
  • During exercise (ex. Running a race) = ASAP = high glycemic index foods
  • Before exercise = in a while = low glycemic index foods
  • Post workout = quick for faster recovery = high glycemic index foods to replenish glycogen stores faster

Question 4

The interaction of carbohydrate loading and training programme modification prior to competition

Answer 4

Carb loading: used to maximize stored glycogen in muscles, requires training + nutrition
More common in people that have significant time during competitions - ex. Marathon, cycling

Training:
* Complete and exhaustive session approximately ~ 1 week prior to the event
* The training load is tapered over the remaining days

Diet:
* Approximately 7 to 4 days prior the diet is low in CHO (high in fat and protein)
* This increases the activity of the enzyme glycogen synthase
* Results in greater glycogen storage when CHO diet increases → because the body was starved from carbohydrates
* The final ~ 2 days has a high CHO diet