Fuels Needed for Exercise

Body Tries to be most Efficient
	At low intensities, most efficient source of fuel is Fat
	Body metabolizes fat and some carbohydrate
	As intensity increases, demand for ATP also increases
	Fat production of ATP falls short, so more carbohydrate is converted to fuel

	During maximal exercise, carbohydrate is the fuel source
	Prolonged exercise uses a combination of fuels: fat, carbohydrate, and protein

Each fuel source is metabolized differently
	Therefore, each produces differing amounts of by-products (such as CO2)
	Ratio between CO2 production and O2 use is Respiratory Exchange Ratio (RER) - VCO2/ VO2

	Fat has an RER of .7
	Carbo has an RER of 1.0
	Protein RER is .8
		- is more accurately measured by Urinary Nitrate (UN)

	Normal RER is about .83-.85



Cellular Adaptations to Training


Basically have Two (2) sets of Muscle Fibers
	FG: Fast (40-60 ns), Forceful, Fatigueable
	SO: Slower (80-100 ns), Weaker, Less Fatigueable

Training enhances these qualities, and also emphasizes these qualities in the FOG Muscle Fibers

What does Endurance Training do ?

	Myoglobin Increases
		able to move more O2 and CO2 within the sarcoplasm (to and from the mitochondria)

	Mitochondral Enzymes Increase
		more available enzymes result in faster mitochondral production of energy

	Mitochondral Size and Amount Increases
		this is the most well documented response
		should be easily seen how this influences energy production

	Enhancement of the Glucose - Alanine Cycle
		more Pyruvate is converted to Alanine and less to Lactate
		Alanine converted to Glucose in the liver
		No Lactate available to inhibit contractions

	Enhanced Glycogen Stores
		Body is able to store and utilize more muscle glycogen


What does Sprint Training do ?

	Research suggests that Maximal Effort results in depletion of the Phosphagen Stores
		CP is used to replace the P to convert ADP to ATP
		CP is exhausted
	Evidence of Lactate build-up also helps with fatigue

	CP stores increase
	Tolerance to Lactic Acid Increases
		able to buffer acid better  (ex: HCO3 + H+ ==> CO2 + H20 )
	Mitochondral Enzymes Increase
		Possibly in response to removal of Lactic Acid
	Glycolytic Enzymes increase
		able to perform Glycolysis more readily
	Conversion of FOG Muscle Fibers to SO Fiber Properties


Strength Training

	Muscle Hypertrophy Occurs
		size of fibers grow
		amount of CP and Glycolytic enzymes increases
		able to have more forceful contractions

	Hyperplasia probably occurs
		Splitting of Muscle Fibers has been documented in Cats and Rats
		has not been documented in Humans (Biopsy of well trained athletes)
	Mitochondral Density Decreases
	Conversion of FOG Muscle Fibers to FG Fiber Properties

Should see that the two types of training Offset one another