Training Adaptations

LIVER

SKELETAL MUSCLE TISSUE

Adrenal Gland

Adipocytes

Mitochondria

TRAINING WILL:

Decrease RER

Does not effect sub-max oxygen uptake

Increases LT and lowers muscle and blood lactate at any sub-max workload

Aerobic training can cause 50-100% increases in mitochondrial mass per gram of skeletal muscle.

However, when express per gram of mitochondrial protein training does not alter specific activity.

Total CHO:

Pre = 145 umol/min

Post = 100 umol/min

or a 50% decrease

This is due to decrease reliance on blood glucose and muscle glycogen

Training decreases Ra(rate of appearance) of glucose from the liver. This means less glycogen depletion in liver.

Muscle Glycogen Depletion

With training you can double your mitochondrial mass, thus at any giving work load each mitochondrion will only be working (ie producing ATP) at half the rate it was before training. The main stimulus for increases in oxidative phosphorylation is ADP. Therefore the increase in intracellular ADP must be less in trained individuals.

blood lactic acid

Training Adaptations

# mitochondria

epi/norepi release during exercise

muscle & liver glycogen use

intramuscular fat use

# MCT’s (via mitochondria)

CAT I (ß-oxidation)

cAMP

Training Adaptations (cont.)• Two major changes that occur with training

1.) # mitochondria in muscle cellscan be doubled at most

2.) epi/norepi release during exercisetraining sympathetic activity at any given work load

Benefits of adaptations to training• 1.) Glycolysis

– Spares CHO, liver glycogen– maintains blood glucose (CNS)– mechanisms:

catecholamines PFK activity mitochondria faster ATP generation,

[AMP&ADP] PFK activity2.) Blood Lactic Acid

keeps blood pH normalmechanisms:

glycolysis mitochondria (more MCTs)

Benefits of adaptations to training (cont.)

• 3.) Fat use fat use from adipocytes via epi/norepi fat use from intramuscular TGs– mechanisms:

mitochondria (via in CAT I activity)

• acetyl CoA production PFK glycolysis

Take home point:*Training glycolysis & Fat use via mitochondria & catecholamines*

Muscle Glycogen vs. FFA Expenditure