Where does immediate energy come from?
The ATP-PC System
How much energy is stored in our muscles?
ATP=5 mmol/kg
PCr=15mmol/kg
What is the purpose of creatine?
to improve muscle performance, promote strength, recovery and performance
What is the creatine loading protocol?
-0.3g/kg/day of creatine for at least 3 days then 3-5g/day to maintain elevated stores
Theoretical basis for creatine?
- creatine phosphate stores limit ATP production and performance during maximal exercise conducted over short periods of time
- so supplementation will increase cellular CP level and increase the duration of high intensity performance
Where does short term energy come from?
The Lactic acid system
Where does the ATP from the Lactic Acid system come from?
- ADP comes from glucose and stored glycogen
- system is used with the ATP-PC system is depleted or if oxygen supply is inadequate (or oxygen demand exceeds oxygen utilization)
Blood Lactate accumulation
when lactate removal is slower than lactate production does
2 classifications of fatigue?
central and peripheral
Central fatigue
not localized in a specific muscle and affects the entire body
-CNS, metabolic, and psychological factors
Peripheral fatigue
- exhaustion: depletion of energy substrates (ATP, CP, glycogen)
- accumulation: of metabolic by products (H+ from lactic acid)
Bicarbonate Loading
loading with sodium bicarb has been proposed to push back the lactate threshold
and bicarb can push accumulating lactic acid from muscle into extracellular spaces for disposal and limit fatigue
Bicarb loading protocol
-household sodium bicarb mixed with water
acute method: 0.3g/kg of body weight 1 hr before competition
chronic method: 0.5g/kg divided in 4 doses throughout the 5/6 days leading up to the event
Side effects of bicarb loading
G.I distress (nausea, stomach pain, diarrhea, vomiting), can interact with other supplements and foods
What system do you use if you need long term energy?
The Aerobic system
Oxygen uptake
the use of oxygen by cells
Steady state
the plateau of oxygen uptake around 3-4 minutes after oxygen uptake rises rapidly and then remains stable
What does aerobic metabolism require?
carbs (glycogen and glucose)
fats (triglycerides and fatty acids)
McArdle’s syndrome
Inborn error in muscle glycogen metabolism
- cannot synthesize phosphorylase
- so you can’t break down glycogen in the muscle
- muscle fibres are broken which leads to muscle pain, cramping, fatigue and tenderness
Goal of carbohydrate loading
muscle glycogen super compensation
-larger glycogen stores help to ensure the body stays in steady state aerobic metabolism which increases endurance
Carb loading approach
- taper training 6-7days prior to event
- gradually increase carb to 65-70% of total calories
Benefits for carb loading
- will only benefit endurance athletes
- need to be exercising for 90mins or more
- can nearly double muscle glycogen concentrations=increased endurance
Downside of carb loading
- for every g or glycogen store 4g are also stored
- muscle stiffness, heaviness and cramping
- risk for glycogen deposition in cardiac muscle
When is protein used as fuel?
only if carb is not available
glucogenic AA are converted to glucose through gluconeogenesis and then glucose is used to generate carbs
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Lecture 118
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Lecture 214
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Lecture 327
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Lecture 432
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Lecture 4 Part 213
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Lecture 522
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Lecture 628
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Nutritional Ergogenic Aids26
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Assessment of Body Size and Composition29
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Nutrition for Body Builders13
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Management of Diabetes and Exercise18
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Disordered Eating and The Female Athlete Triad29
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Sport Nutrition for Child and Adolescent Athletes4
