Physiology Training Flashcards
Overload
Training effect occurs when a system is exercised at a level beyond which it is normally accustomed with respect to intensity, duration, and frequency
Specificity
Muscle adapts specifically to the type of activity
Mitochondrial and capillary adaptations to
endurance training
Contractile protein adaptations to
resistance training
Training effect is specific to
- Energy System (aerobic vs. anaerobic)
- Muscle Fibers involved
- Type of contraction (eccentric, concentric, isometric)
- Velocity of contraction
Reversibility
Gains are lost fairly quickly when overload is removed
Endurance Training to increase VO2max
- Large muscle groups, dynamic activity
- 20 -60 min 3-5 times/week at 50-85% VO2 max
- HIIT, 30 sec-3min intervals at greater than or equal to 85% VO2 max or 75-175% PPO interspersed with rest or low intensity intervals for recovery, 20-25 min, 6 sessions over a 2 week period is an example HIIT program.
Expected increases in VO2 max with endurance training
- Average = 15-20%
- 2-% in those with high initial VO2 mac - requires an intensity of > 70% VO2 max
- Up to 50% in those with low initial VO2 max - initial training intensity of 40-50% VO2 max
Genetic Predisposition and endurance training
Accounts for about 50% of VO2 max and is a prerequisite for bery high VO2 max
The HERITAGE Family Study
Designd to study the role of genotype in cardiovascular, metabolic, and hormonal responses to exercise and training
Results of the Heritage Family Study
- Heritability of VO2 max is 50%
- Large variaton in change in VO2 max with training (20 week endurance training program)
2a. average improvement is 15-20%
2b. Ranged fro no improvement to 50% increase
2c. heritability of change in VO2 max is 47%
3 21 genes play a role rleated to adaptations and improvements in VO2 max with training
Fick Equation
VO2max = HR max x SV max x (a-vO2) max
Stroke Volume
EDV-ESV or Preload x Contractility x afterload
Differences in VO2 max in different populations is primarily due to
differences in SV max
Improvements in VO2 max
- Overall 40% increase in SV and a-vO2
- Shorter duration training (4 months) - SV increase is greater than the increase in a-vO2
- Longer duration training (28 months) - increase in a-vO2 is greater than the increase in stroke volume
Increase maximal stroke volume by
increasing preload, decreasing afterload and increasing contractility
Increased preload (EDV) due to
increased plasma volume, increases venous return and increases ventricular volume
Decreased afterload (TPR) due to
decreased arterial constriction and increased maximal muscle blood flow with no change in MAP
Increase in contractility is due to
upregulated calcium release and uptake in myocardium
Changes to stroke volume occur rapidly - within six days of training
- 11% increase in plasma volume
2, 7% increase in VO2 max - 10% increase in stroke volume
A-VO2 difference occur because of an
increase in muscle blood flow and an improved ability of the muscle to extract oxygen from the blood
Muscle blood flow increases because if a
decreases in SNS vasoconstriction to trained muscle
Improved ability of the muscle to extract oxygen from the blood occurs because of an
increase in capillary density, and an increase in mitochondrial number
An increase in capillary density occurs because of
decreased diffusion distance to the mitochondria slow blood flow through the muscle to allow more time for O2 diffusion from capillary to muscle fiber.
The ability to perform prolonged, submaximal work is dependent on
the maintenance of homeostasis during the activity
endurance training causes
- More rapid transition from rest to steady state
- Reduced resilance on glycogen stores from liver and muscle
- CVS and thermoregulatory adaptations.
- Improved neural and or hormonal receptor function likely precedes biochemical adaptations in skeletal muscle
- Structural and biochemical changes in muscle
Structural and biochemical changes in muscle with endurance training
- Increased type 1 fiber percentage
- Increased mitochondria
- Increased ability to metabolize fat for fuel
- Increased muscle anti-oxidant capacity
- Increased capillary density
Endurance training causes a shift in muscle fiber types from -
fast to slow shift in muscle fiber types with a
- reduction in fast myosin
- increase in slow myosin
- extent of change determined by duration of training and genetics
Endurance training causes an increase number of
capillaries with enhanced diffusion of oxygen and increased removal of waste
Endurance training increases _______ content in skeletal muscle
Mitochondria
2 sub populations of mitochondria in the muscle
subsarcolemmal and intermyofibrillar
Subsarcolemmal Mitochondria
Located below the sarcolemma
Intermyofibrillar Mitochondria
are located around the contractile proteins 80% of total mitochondria making up the larger population
Mitochondrial content increases quickly depending on
intensity and duration of training - you can see an icnrease of 50-100% within the first 6 weeks
Mitochondrial content changes result in
increased endurance performance due to changes in muscle metabolism
Intracellular signaling and Inhibition of Protein Synthesis
Signaling pathways during concurrent resistance and endurance training.
AMPK activation causes
inhibition of mTOR via TSC1/2
AMPK activation supresses
resistance training induced protein synthesis
Mechanisms of Impairment of Strength Development
- Neural Factors
- Low Muscle Glycogen Content
- Overtraining
- Depressed protein synthesis
Neural Factors that impair strength development
Impaired motor unit recruitment and force productions - limited evidence
Low muscle glycogen content impairs strength development by
Due to successive bouts of endurance exercise - low glycogen content can therefore reduce the intensity at which you can perform subsequent resistance training sessions which would decrease the ability to adapt and gain strength
Overtraining
Imbalance between training and recovery
There is no direct evidence that
overtraining occurs when combining strength training with endurance training
Depressed protein synthesis impairs strength development by
endurance training adaptations (from AMPK signaling and increases in mitochondrial biogenesis) interferes with protein synthesis.
TSC1/2
tuberous sclerosis complex 1/2
Concurrent Strength and Endurance Training causes a potential for interference of adaptation
- Endurance training increases mitochondrial proteins
- Strength training increases contractile proteins
- Depends on intensity, volume, and frequency of training
Studied report that combining Strength and endurance training impairs
Strength gains overall - it depends on intensity, volume and frequency of training
31% decrease in strength after
30 weeks but very little atrophy during this time
Loss in strength during detraining is mostly related to
the neural component
Rapid gains in strength and fiber cross- sectional area with just 6 weeks of
retraining back to pre-training levels or better