Effects of training Flashcards
Change VO2max with endurance training programme?
increase 15-20%
high initial = 2-3% increase - require high intensity exercise to improve
low initial = 50% increase
Genetics determine training response
low responders = 2-3% increase VO2max
high = 50% with rigorous training
heritability of training adaptations is ~47%
Why does training imrpove VO2max?
VO2max = max CO x max a-VO2 diff
short duration improvements = increase SV
long duration = SV + a-VO2 increase
How does endurance training increase SV
increase preload (EDV)
increase plasma volume
increase venous return
increase ventricular volume
increase contractility
decrease afterload (TPR)
Max HR
lower after training due to:
vagal tone increased
greater filling time (EDV)
Training-induced increases in arteriovenous O2 difference
- muscle blood flow increases
- improved ability of muscle fibres to extract and utilize O2 from blood
Muscle blood flow increases
decrease SNS vasoconstriction
increase diameter and compliance of arteries
specific = permits greater volume flow per beat to limb
Improved ability of muscle fibre to extract and utilize O2 from blood
increase capillary density
increase mitochondrial number/volume
decrease diffusion distance
Time of adaptations
double within 5 weeks of training
improved oxidative capacity and ability to utilize fat as fuel
muscle mitochondria adapt quickly
Vascular remodeling on muscle blood flow
av differance greater = better O2 extraction
Shift in muscle fibre type
fast to slow twitch type
reduction in fast
increase in slow
increase in slow myosin isoform = lower myosin ATPase activity but better efficiency with less ATP utilization
Increased number of capillaries surrounding muscle fibre
enhanced diffusion of oxygen
improved removal of wastes
Increase mitochondrial volume
greater capacity for oxidative phopshorylation
decreases cytosolic (ADP) due to increased ADP transporters (faster O2 uptake)
less lactate and H+ formation
less PC depletion
Increased mitochondrial turnover
breakdown of damaged mitochondria
replacement with healthy mitochondria
Endurance training fuel utilization
increased utilization of fat
sparing of glucose and muscle glycogen
decrease glucose metabolism
Improve plasma FFA transport and oxidation into muscles
increased fatty acid binding protein and fatty acid translocase (FAT)
Transport FFA from cytoplasm to mitochondria
higher levels carnitine transferase and FAT
Mitochondrial oxidation of FFA
increased enzymes of B-oxidation
increased rate of acetyl-CoA formation
Free radicals
contracting skeletal muscles produce
contain upaired electron
highly reactive
damage proteins, membranes, DNA
promote oxidative damage/muscle fatige (interfere with actin-myosin crossbridge formation)
Primary changes in skeletal muscle as a result of endurance training
shift muscle fibre type
increase number capillaries
increase mitochondrial volume/turnover
increase fat metabolism
improve antioxidant capacity of muscles
improve acid-base balance
Improve acid-base balance
increase mitochondrial number
less carb utilization = less pyruvate formed
increase NADH shuttles via ETC= less NADH available for acid formation
change LDH isoform
increase mitochondrial uptake of NADH and pyruvate = maintain blood pH
Endurance + resistance training
promote protein synthesis
4 primary signals
mechanical stretch
calcium
AMP/ATP
free radicals
List 3 secondary signals
AMP kinase
PGC-1x
MTOR
AMP kinase
AMPK
important signaling molecule activated during endurance exercise
promotes glucose uptake
linked to gene expression by activation of transcriptional activating factors
PGC-1x
master regulator of mitochondrial biogenesis
promotes angiogenesis (increased capillarization)
synthesis of antioxidant enzymes
activated by AMPK and CaMK
mTOR
key in resistance training adaptations
protein kinase-major regulator of protein synthesis and muscle size
Causes of decrease in VO2max with detraining
decrease SV max due to rapid loss plasma volume
decrease VO2max due to decrease SV max
later decrease due to decrease a-v O2max
Decrease max a-v O2 difference
decrease mitochondria
decrease oxidative capacity of muscle
decrease type 2a fibres
increase type 2x fibres
Changes in muscle anaerobic exercise
improve muscle buffer capacity - increase H+ transporters/increase mitochondrial volume
hypertrophy type 2 fibres
elevates enzymes involved in ATP-PC system and glycolysis
Capacity to transport glucose into skeletal muscle fibres
increased following several weeks of endurance exercise training
due to increase in number of GLUT4 glucose transporters
