IPHY 4650 - Exercise physiology Flashcards
CHAPTER 13/14/20 : Principles of training
Explain the basic principles of training : overload, reversibility, and specificity
- Overload : increase capacity of a system in response to training level to which it is accustomed ; determined by : intensity, duration, and frequency ; too much leads to overtraining and overreaching
- Reversibility : when training is stopped, training effect is quickly lost
- **Specificity **: training effect is specific to –> muscle fiber recruited during exercise ; type of contraction (eccentric , concentric, and isometric) ; energy system involved (aerobic vs anaerobic)
CHAPTER 13/14/20 : Principles of training
Explain the basic principles of training : Discuss the impact of sex
men and women respond similarly to training programs –> exercise perscriptions should be individualized
CHAPTER 13/14/20 : Principles of training
Explain the basic principles of training : initial fitness level
training improvment is always greater in individuals w/ lower intial fitness : 50% incerase in VO2max in sedentary adults; 10-20% improvment in normal, active subjects; 3-5% improvment in trained athletes
ex: VO2 max of highly trained rowers, cyclists, cross country skiers –> Vo2max attained by all athletes during their sport -specific activity was high (or higher) than those values obtained on a treadmill
CHAPTER 13/14/20 : Principles of training
Explain the basic principles of training : genetics on VO2 max
gentics plays an important role in how an individual responds to training ; ex: ten pairs of identical twins in a 20 wk program, similarly in response of each twin pair, improvment in VO2 max varied from 0 to 40%
- high responders : genotype E –> ideal genetic makeup for enduance athletes , high untrained VO2 max
- low responders: genotype A –> low untrained VO2 max , limited training response ; anaerobic capacity is genetically determined more than aerobic
- anaerobic capacity more genetically determined than aerobic b/c training can improve anaerobic perfomance to a small degree , also dependent largely on fast (IIx) fibers –> determined in early development
CHAPTER 13/14/20 : Principles of training
Physiological Effects of Aerobic (Endurance) Training : Adaptations in Muscle : Discuss the primary changes that occur in skeletal muscle as a result of endurance training, including changes to muscle fiber type size, capillary density, myoglobin content, and mitochondrial volume and function.
repeated excitation and contraction of muscle fibers during endurance training stimulate changes in their structure and fxn :
- Muscle fiber type : fast to slow shift in muscle fiber type –> reduction in fast fibers and increase in number of slow fibers ; –> magnitude of fiber type change determined by duration of training, type of training, and genetics
- Capillary density : increase number of capillaries surrounding muscle fibers –> enhanced diffusion of oxygen and improved removal of wastes
- ** Myoglobin content **: endurance training increase muscle myoglobin content 75 and 80 % –> supporting a msucle’s increased capacity for oxidative metabolism after training ; exercise-induced signaling –> primary and secondary signaling molecules contribute to exercise - induced adaptation to endurance training- induced adapations => promotes increase in protein synthesis and mitochondrial formation due to higher activation of PGC-1 alpha ; two approaches : 1) resticting dietary carobohydrates => may cause fatigue and limit training ; 2) twice per day (every other day) => second training session w/ lower muscle glycogen
- mitochondrial function / oxidative enzymes : muscle mitochondria adapt qucikly to training –> doubles w/in 5 weeks of training ; endurance training increases the volume of both subsarcolemmal (SS) and intermyofibrillar (IMF) mitochondria in muscle fibers : results in improved oxidative capacity and ability to utilize fat as fuel ; increase mitochondiral turnover (breakdown of damaged mitochondria and replacement with healthy mitochondria aka mitophagy) ; mitochondrial volume increase : results in greater capacity for oxidative phosphorylation ; increased mitochondrial vol decreases cytosolic (ADP) due to increase ADP transporters in mitochondrial mbn –> less lactate and H+ formation ; less PC depletion –> endurance exercise training reduces O2 deficit at ondet of work
CHAPTER 13/14/20 : Principles of training
Metabolic Adaptations to training : Discuss the primary metabolic changes that occur as a result of endurance training
**Effect of training on muscle fuel source **: endurance trained athletes use more fat and less carbs than less fit athletes during prolonged exercise at the same intensity
CHAPTER 13/14/20 : Principles of training
Metabolic Adaptations to training : Explain how endurance training alters substrate utilization during prolonged exercise
Effect on mitchondria and capillaries : a free fatty acid and glucose utilization –> increase FFA => results increase beta oxidation enzymes and carnitine transferase , capillary density , and mitochondrial number
CHAPTER 13/14/20 : Principles of training
Metabolic Adaptations to training : Explain how endurance training improves acid-base balance during exercise and lactate threshold
increase in mitochondria –> results in increase FFA beta oxidation and decrease in decrease in PFK activity –> increase mitochondrial uptake of pyruvate and NADH , a decrease in lactate and H+ formation => results in blood pH being maintained
**lactate threshold **: in trained state, one can exercise at a higher % of one’s VO2 max before lactate beings to accumate in the blood
CHAPTER 13/14/20 : Principles of training
Cardiovasuclar Adaptations to Training : List typical VO2 max values for sedentary versus active populations
Untrained women = 38
Untrained men = 44
Female Athletes = 55
Male Athletes = 71
CHAPTER 13/14/20 : Principles of training
Cardiovasuclar Adaptations to Training : Explain how training increases VO2 max. Include in your discussion the contribution of
heart rate:
- Explain how endurance training changes resting, submaximal, maximal, and recovery heart rate
Heart Size : as an adaptation to the increase work demand, cardiac muscle mass and ventricular volume increas
Resting HR : decreases as a result of endurance training ; can be as low as 30 to 40 bpm in highly conditioned athletes
Submax and Max HR : aerobic training results in lower HR at any given absolute value exercise intensity ; max HR typically remains relativley unchanged ( or may slightly decrease) after training
Recovery HR: after endurance training, HR returns to resting level much faster after exercise bouts than before training
CHAPTER 13/14/20 : Principles of training
Cardiovasuclar Adaptations to Training : Explain how training increases VO2 max. Include in your discussion the contribution of
stroke volume,:
- Explain how endurance training increases stroke volume.
SV influenced by : Increase in EDV (preload); increase in contractility; decrease in TPR ( afterload) ; increase in plasma volume; increase in ventricular volume; increase in filling time and venous return
increased SV at rest in edurance athletes –> improved ventricular filling b/c of braycardia
SV may not plateau in elite endurance athletes b/c they are subject to improved ventricular filling and increased in EDV and SV at higher HR
CHAPTER 13/14/20 : Principles of training
Cardiovasuclar Adaptations to Training : Explain how training increases VO2 max. Include in your discussion the contribution of
a-vO2 difference :
- Explain how endurance training increases the (a-v)O2 difference.
Increase in muscle blood flow –> decrease in SNS vasoconstriction –> improved ability of muscle to extract oxygen from the blood => increased capillary density => slows blood flow through muscle and increase mitochondria number
Blood Volume –> endurance training increases total blood volume; and this effect is larger at higher training intensities : increase plasma volume and increase if RBC; and decrease of hematocrit (“psudoanemia”)
FICK Equation : b/c HR max either stays the same or it decreases, increase in VO2 max depends on adaptations in SV max and max a-vO2 diff => VO2max = CO max * max (a-v)O2diff (CO max = HRmax * SVmax)
CHAPTER 13/14/20 : Principles of training
Respiratory Adaptations to Training : Discuss the primary respiratory changes that occur as a result of endurance training,
including changes to submaximal and maximal ventilation during exercise
Pulmonary Ventilation –> ventilation is lower during submax exercise following training ; max pulmonary ventilation id substantially increased
CHAPTER 13/14/20 : Principles of training
Respiratory Adaptations to training : How does training affect the ventilatory threshold?
respiratory system fxn does not usually limit performance b/c ventilation van be increased to a much greater extent than CVD fxn, no effect on lung strx and fxn at rest
CHAPTER 13/14/20 : Principles of training
Respiratory Adaptations to training : List typical pulmonary ventilation values for sedentary versus active populations.
Females Untrained (85)
Females Trained (110)
Males Untrained (142)
Males Trained ( 160)
measured in L/min
NOT INCLUDED
CHAPTER 13/14/20 : Principles of training
Detraining Following Endurance Training : Describe the underlying causes of the decrease in VO2 max that occurs with cessation of
endurance training.
Detraining following endurance training –> detraining changes in VO2 max and CVD varibales : inital VO2 max (12 days) decreases b/c decrease in SV max –> HR and (a-vO2)diff remeained the same or increased ;* later decrease due to a decrease* a decrease in (a-vO2)difference -> decrease in mitchondria, no change in capillary density
mitchondrial adaptations lost quickly with detraining : requires 3 to 4 weeks or retraining to regain mitochondrial adaptations
CHAPTER 13/14/20 : Principles of training
Endurance Training: Links Between Muscle and Systemic Physiology
* Explain what is meant by “lack of transfer” of a training effect in endurance exercise
**Lack of transfer of a training effect **–> responses of the cardiovascular, pulmonary, and SNS are more dependent on the trained state of the muscles involved in the activity than some adaptations in those systems.
CHAPTER 13/14/20 : Principles of training
Physiological Effects of Strength (Resistance) Training
* Contrast the role of neural adaptations with hypertrophy in the increase in strength that occurs with resistance training
responsible for early gains in strength –> inital 8-20wks
increased neural drive => increase # of motor units recruited; increase firing rate of motor units –> increase in motor unit synch –>
improved neural transmission across neuromuscular junctions
CHAPTER 13/14/20 : Principles of training
Physiological Effects of Strength (Resistance) Training: Discuss to what extent fiber hypertrophy and fiber hyperplasia contribute to chronic muscle hypertrophy in humans
Hyperplasia : increase in muscle fiber #; unclear occurance
Hypertrophy : increase in CSA of muscle fibers
Hypertrophy is a likely dominant factor in resistance training –> induces an increase muscle mass;
Hypertrophy due to increased muscle proteins (actin and myosin)
**Resistance training induced hypertrophy + myoniclei **=> resitance training results in parallel increase in muscle fiber CSA & increase # of myonuclei
genetic influence –> Approx 80 % of the differences in muscle mass btwn indivduals is due to genetic variation
CHAPTER 13/14/20 : Principles of training
Physiological Effects of Strength (Resistance) Training: Identify the primary changes that occur in skeletal muscle fibers in response to resistance training
**Fast to slow shift in fiber type **: from type IIx to IIa; 5-11 % changes in 20 wks of training ; substanital increase in strength and CSA (cross sectional area) of all fiber types ; study noted following a 20 wk resistance training program ; mean % of IIx fibers decreased significantly, but the mean % of type IIa fibers increased
CHAPTER 13/14/20 : Principles of training
Detraining Following Strength Training
* Discuss how detraining following strength training affects muscle fiber size and strength.
* Explain how retraining affects muscle fiber size and strength.
Detraining: inactivity -induced muscles atrophy occurs due to decrease in protein synthesis and increase in protein breakdown; inactive protein synth decreases; protein degragation occurs twice as fast vs active muscle where protein synth occurs twice as fast while degragation decreases
Retraining : cesation of resistance training results in muscle atrophy and a loss of strength ; compared to endurance training, the rate of detrainng (strength loss) is slower,
recovery of dynamic strength loss can occur rapidly w/in 6 wks of retraining
CHAPTER 13/14/20 : Principles of training
Concurrent Strength and Endurance Training
* Discuss how concurrent strength and endurance training can impair strength gains.
Concurrent strength and endurance training : perform stenth and endurance training on alternate days for optimal strength gains; athletes whose sport requires max strength should avoid concurrent training, perfomance of combined –> does not impair training induced increase in endurance
- combined strength and endurance training may limit strength gains vs strength training alone
- it depends on the training state of subject, volume, frequency or training, way two methods are integrated, endurance training more than 3 days /wk and 30 to 40 min/day
Impairment of strength: *1) neural factors *–> impaired motor unit recruitment; limited evidence exsists to support concept ; 2) overtraining–> no direct evidence exisits to prove overtraining contributes impairment of strength gains during concurrent training ; 3) depressed protein synthesis : edurance training cell signaling can interefere w/ protein synthesis => via inhibition of mTDR activation of AMPK
CHAPTER 13/14/20 : Principles of training
Common Training Mistakes
* List and discuss several common training errors.
* Explain the physical signs of overtraining and provide recommendations for this problem.
* Describe the key differences between tapering and detraining.
-strux of a traditional periodized training program => model varies the training load, overload time to achieve acute overload and some overreaching while avoiding overtraining
- **the 10% rule: for increasing training load -> increase intensity or duration </= 10% per wk
- symptoms of over training **-> decrease in perfomance, loss of body weight, chronic fatigue , increase # of infection; psychological staleness; evelvated HR and blood lactate levels during exercise
- Undertraining : minor physioloical adaptations and no change in performance
- **Acute overload **: positive physiological adaptations and minor improvments in perfomance
- overreaching : optimal physiological adaptations and perfomance
- **over training **: physiological maladaptations, perfomance decrements, and overtraining syndrome
- Tapering: short term reduction in training load prior to comp –> allows muscles to resynth glycogen and heal from training induced damage ; improves perfomance in both strength and endurance evens –> athletets can reduce training load by 60% w/o reduction in perfomance
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