Chapter 13/14/20 Flashcards
Physiology of Training (85 cards)
Three principles of training
- Overload
- Reversibility
- Specificity
Principles of training
Overload
what is it, what is it dependent on, too much?
Increased capacity of system in response to training above the level to which it is accustomed
* Dependent on intensity duration and frequency
* Too much leads to overtraining or overreaching
Describe the graph of acute overloading/overeaching showing performance vs. time
Principles of training
Reversibility
when training stopes, the training effect is quickly lsot
Describe the graph of reversibility (measure of fitness vs. time) in respect to detraining and overtraining
Principles of training
Specificity
training effect is specific to…
Training effect is specific to:
* Muscle fibers recruited during exercise (depends on type of exercise you’re doing)
* Type of contraction (eccentric, concentric, isometric)
* Energy system involved (aerobic vs. anaerobic)
Example of specificity for VO2max in sport-specific activities vs. treadmill
VO2 max of rowers,
cyclists, and cross-country skiers was
tested: uphill running on a treadmill
and during their sport-specific activity.
VO2 max attained by all athletes
during their sport-specific activity was
as high (or higher) than those values
obtained on a treadmill.
Training causes specific adaptations
Influence of sex on % strength improvement
men and women respond similarly to training programs
- exercise prescriptions should be individualized but % improvements are similar
Influence of initial fitness level on VO2max improvements
% improvements based on fitness
magnitude of training improvement is always greater in individuals with lower initial fitness (more room to improve)
* 50% increase in VO2max in sedentary adults
* 10-20% improvement in normal, active subjects
* 3-5% improvement in trained athletes
Influence of genetics on VO2max improvements (twin study)
genetics plays important role in how an individual responds to training (but does not account for 100% of improvement)
twin study - similarities but improvment in VO2max varied from 0-40%
Does genotype affect training-induced changes in VO2max
yes lots of variation between genotypes
High responders vs low responders
High responders (genotype E): ideal genetic makeup required for champion endurance athletes
* high untrained VO2max
* larger heart, lungs, or taller
Low responders (genotype A): limited exercise training response
* low untrained VO2max
What area of exercise improvement does genetics mainly determine
anaerobic capacity = more genetically determined than aerobic capacity
* training only improves anaerobic by a small degree
* Dependent largely on fast (IIx) fibers = determined early in development
Labratory tests to quantify endurance exercise potential
3 pillars of performance
- VO2max: how big is the engine
- Economy: how efficiently you use oxygen
- Lactate threshold/ventilatory threshold: how close to VO2max can i sustain for long periods of time
adaptations in muscle
repeated excitation/contraction of muscle fibers during endurance training stimulates changes in structure and function such as changes to
- muscle fiber type
- capillary density
- myoglobin content
- mitochondrial function
- mitochondrial oxidative enzymes
Edurance training effect on muscle fiber type
Fast-to-slow shift
* reduction in cross-sectional area of fast fibers, increase in slow fibers
* Magnitude of change determined by duration of training, type of training, and genetic
Effect of endurance training on capillary density
increased # of capillaries surrounding muscle fibers = more diffused blood thats able to move slower
* enhanced diffusion of oxygen
* Improved removal of waste
Effect of endurance training on myoglobin content
increases muscle myoglobin content by 75-80%
* More myoglobin = more O2 delivery to mitochondria
* Helps support oxidative metabolism after training
Time course of training adaptations in mitochondria
muscle mitochondria adapt quickly to training - double within 5 weeks
Effect of endurance training on mitochondrial volume and turnover
increases the volume of both subsarcolemmal (SS) and intermyofibrillar (IMF) mitochondria in muscle fibers
* improved oxidative capacity (shared load) and ability to utilize fat as fuel (multiple working at the same time to create same amount of ATP while preserving glycogen stores)
increases mitochondria turnover (breaking down of damaged mitochondria and replacement with healthy)
* this is termed mitophagy (recycling mitocondria)
significance of increased mitochondrial volume
in terms of ADP and oxidative phsophorylation
increased mitochondria volume =
* greater capacity for oxidative phosphorylation
* decreases cytosolic [ADP] due to increased ADP transporters in mitochondria membrane resulting in less lactate and H+ formation and less PC depletion
utilizing more areas of mitochondria for same amount of energy
Explain why endurance exercise training-reduces the O2 deficit at the onset of work
increases in mitochondria density and volume allows more oxygen consumption = faster rise to steady state
energy cost remains the same, its about how quickly you can generate energy sources
PGC-1a
what activates it, what does it do
secondary signaling molecule that increases with endurance training
* acts on all three adaptations: fast-to-slow fiber type shift (increased protein synthesis), mitochondrial biogenesis, and synthesis of antioxidant enzymes
* low muscle glycogen activates PGC-1a
Is low muscle glycogen a positive influence on endurance training-induced adaptations?
yes, because it activates PGC-1a which promotes adaptations protein synthesis and mitochondria formation