Adaptations to Aerobic Training 2

Changes in fiber type

Type II - Type I

Type IIx may perform more like Type

IIa

Capillary supply adaptation

increase in number of them supplying each fiber (angiogenesis)

What may be a key factor in increase in VO2 Max?

Increase in number of capillaries supplying each fiber

Angiogenesis

increase in capillary numbers in skeletal muscle

Myoglobin aerobic adaptations

increase in its content by 75% to 80%

supporting increase in oxidative capacity in muscle

Mitochondrial aerobic training adaptatiion

increase in size and number

highly correlated with training volume

Mitochondrial clearance

more good mitochondria, taking away bad/weakened mitochondria

Oxidative enzymes

Succinate dehydrogenase (SDH)

Citrate synthase (CS)

Succinate dehydrogenase (SDH) → Citrate Synthase (CS)

increased activity with training volume

continued increase even after VO2max plateus with training

enhanced glycogen sparing

Volume and SDH activity are

directly correlated

Increased calcium concentration

Calcineurin, CaMK

Low ATP availability (increased AMP/ATP)

AMPK

Increased oxidant stress

p38, NFkB

Master switch

PGC-1α

Why is PGC-1α the “master switch”

in controls the adaptations

Main adaptations that lead to improved muscular endurance

fiber type changes (fast to slow)

increase in health mitochondria

oxidative enzyme production

PGC-1α is crucial for

mitochondrial biogenesis

Lactate threshold adaptations

increase to higher percentage of VO2ma

decrease in lactate production, increase in lactate clearance

allowing higher intesnity without lactate accumulations

Respiratory exchange ratio adaptations

decrease at both absolute and relative submaximal intensities

increase dependency on fat, decreased dependency on glucose

RER equations

VCO2/VO2

The highest possible VO2max is typically achieved after

12 to 18 months

Performance continues to increase after VO2max

plateus

Factors dictating individual responses

training status, pretraining VO2max

genes (dictate 50% training adaptations)

Resting VO2 is ______ with training

unchanged

Submaximal VO2 unchanged or ______ with training

decreases slightly

VO2 max increases how much with training

15-20%

VO2 max increases substantially due to

increase in cardiac output and capillary density

Finite VO2max range is determined by

genetics

VO2 max more similar for

identical than fraternal twins

25-50% of VO2max variance due to

genetic factors

VO2max substantially higher in athlete’s

sport-specific activity

The VO2max being higher in that athlete’s sport is likely due to

individual muscle group adaptations