metabolic adaptation 2

8/14/2019 Metabolic Adaptation 2

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Adaptations to TrainingAdaptations to Training

Chronic exercise provides stimulus for theChronic exercise provides stimulus for the

systems of the body to changesystems of the body to change

Systems will adapt according to level,Systems will adapt according to level,

intensity, and volumeintensity, and volume


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Factors that Affect Adaptations toFactors that Affect Adaptations to

TrainingTraining

Specificity of training (figure 1)Specificity of training (figure 1)

Metabolic differences (aerobic vs. anaerobic)Metabolic differences (aerobic vs. anaerobic)

activitiesactivities

Metabolic differences within an activityMetabolic differences within an activity

Genetic endowmentGenetic endowment

Fiber type patternsFiber type patterns

SomatotypeSomatotype ((Ecto,Meso,EndoEcto,Meso,Endo))

Environmental factorsEnvironmental factors


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Factors contFactors cont

Fitness training statusFitness training status

Time course of adaptationsTime course of adaptations

Magnitude of expected changesMagnitude of expected changes

Mechanism of adaptationsMechanism of adaptations GenderGender

Mechanism of adaptationsMechanism of adaptations

AgeAge Children vs. adults vs. older adultsChildren vs. adults vs. older adults


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Metabolic Contributions to ExerciseMetabolic Contributions to Exercise

TrainingTraining

Anaerobic metabolism (figure 2)Anaerobic metabolism (figure 2)

High intensity, short duration exercise = energyHigh intensity, short duration exercise = energyPRIMARILY from storedPRIMARILY from stored phosphagensphosphagens and ATPand ATP

StoredStored phosphagensphosphagens ((creatinecreatine phosphate, CP) arephosphate, CP) are

molecules w/ high energy chemical bonds that whenmolecules w/ high energy chemical bonds that whenbroken down, provide energy for immediate usebroken down, provide energy for immediate use

AnaerobicAnaerobic glycolysisglycolysis (figure 2) utilized at beginning of(figure 2) utilized at beginning of

sustained exercise (regardless of intensity)sustained exercise (regardless of intensity)


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Metabolic Contributions contMetabolic Contributions cont Aerobic metabolismAerobic metabolism

Most of energy (50+%) needed for prolonged exerciseMost of energy (50+%) needed for prolonged exerciselasting more than about 3 min.lasting more than about 3 min.

Krebs Cycle (figure 3) degrades acetylKrebs Cycle (figure 3) degrades acetyl CoACoA into CO2into CO2

and H+ ions and electrons (More ATP Produced)and H+ ions and electrons (More ATP Produced) Electron Transport Chain receives electrons for KrebsElectron Transport Chain receives electrons for Krebs

Cycle and used for oxidativeCycle and used for oxidative--phosphorylationphosphorylation andand

regeneration of ATPregeneration of ATP

Also, free fatty acids enter the mitochondria andAlso, free fatty acids enter the mitochondria andundergo beta oxidation in the Krebs Cycle (fats yieldundergo beta oxidation in the Krebs Cycle (fats yield

the most energy)the most energy)


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Metabolic Contributions contMetabolic Contributions cont

Relative contribution of aerobic &Relative contribution of aerobic &

anaerobic systems (figure 4A and 4B)anaerobic systems (figure 4A and 4B) All energy systems are active at a given timeAll energy systems are active at a given time

Extent to which energy system is usedExtent to which energy system is used

depends on:depends on:

Intensity (primary)Intensity (primary)

Duration (secondary)Duration (secondary)


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Adaptations Following ExerciseAdaptations Following Exercise

TrainingTraining Neuromuscular adaptations (figure 5)Neuromuscular adaptations (figure 5)

Neural adaptations due to:Neural adaptations due to: Changes occurring in activation of motor unitChanges occurring in activation of motor unit

Improved recruitment patternsImproved recruitment patterns

Improvement in neural driveImprovement in neural drive

LearningLearning how to perform the activityhow to perform the activity

DisDis

inhibitioninhibition

also one of the limiting factors in the developmentalso one of the limiting factors in the development

of muscular force, serving as a protective mechanismof muscular force, serving as a protective mechanism Golgi tendon organ (GTO)Golgi tendon organ (GTO)

Exercise training may lead to a reduction in the sensitivity ofExercise training may lead to a reduction in the sensitivity of thesethesereceptors to allow for greater force productionreceptors to allow for greater force production

Exercise training may also lead to increased # of vesicles thatExercise training may also lead to increased # of vesicles thatstorestore acetylchlolineacetylchloline to allow for greater amount ofto allow for greater amount ofneurotransmitter secretion at the neuromuscular junction andneurotransmitter secretion at the neuromuscular junction andallow for greater force productionallow for greater force production


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Adaptations Following contAdaptations Following cont Muscle fiber type adaptationsMuscle fiber type adaptations

Normal recruitment pattern: (Type) INormal recruitment pattern: (Type) I IIaIIa IIbIIb Exercise training results in more precise and efficientExercise training results in more precise and efficient

mode of recruitmentmode of recruitment

Following training, less neural activity required to produceFollowing training, less neural activity required to produceany level ofany level of submaximalsubmaximal force measured by EMGforce measured by EMG

Following training, increased synchronization of motor unitFollowing training, increased synchronization of motor unit

firing increases the amount of time that maximal force outputfiring increases the amount of time that maximal force output

can be sustainedcan be sustained

FiberFiber transformationtransformation ((IIbIIb IIaIIa) may also result in increased) may also result in increased

or altered recruitment patternsor altered recruitment patterns


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Adaptations Following contAdaptations Following cont Muscle fiber type adaptations contMuscle fiber type adaptations cont

Fiber type characteristics (figure 6) and examples ofFiber type characteristics (figure 6) and examples ofsport events (figure 7)sport events (figure 7)

Changes in fiber area (example of a staining, figure 8)Changes in fiber area (example of a staining, figure 8)

Type II fibers will increase in area more than Type I fibersType II fibers will increase in area more than Type I fibers

Increases in fiber area are mediated by the addition ofIncreases in fiber area are mediated by the addition of actinactin

and myosinand myosin myofilimentsmyofiliments to outside of myofibrilto outside of myofibril

Hypertrophy vs. hyperplasiaHypertrophy vs. hyperplasia

Research is still inconclusive in humansResearch is still inconclusive in humans Hypertrophy model is still most commonly supportedHypertrophy model is still most commonly supported

Difficulty in biopsy techniqueDifficulty in biopsy technique


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Adaptations Following contAdaptations Following cont Muscle fiberMuscle fiber transformationstransformations

Exercise results inExercise results in decreasedecrease in Typein Type IIbIIb fibers with a concomitantfibers with a concomitantincreaseincrease in Typein Type IIaIIa fibersfibers

TypeType IIbIIb fibers arefibers are couch potatocouch potato fibers and inversely related tofibers and inversely related toindividuals max oxygen consumption and intensity of training stiindividuals max oxygen consumption and intensity of training stimulusmulus

Type I fibers will show some percent increase after resistance tType I fibers will show some percent increase after resistance training,raining,but significantly more changes after aerobic trainingbut significantly more changes after aerobic training

TransformationsTransformations based on intensity and state of trainingbased on intensity and state of trainingdetrainingdetrainingcausescauses reversalreversal of Typeof Type IIaIIa TypeType IIbIIb

Mitochondrial density increases in aerobicallyMitochondrial density increases in aerobically--trained individualstrained individuals Enzymes (Enzymes (creatinecreatine phosphate andphosphate and myokinasemyokinase) increase due to) increase due toexercise trainingexercise training

NeuroendocrineNeuroendocrine adaptationsadaptations Amount of synthesis and storage of hormonesAmount of synthesis and storage of hormones

Transport of hormonesTransport of hormones Time needed for clearance in tissuesTime needed for clearance in tissues

Amount of hormonal degradationAmount of hormonal degradation

Number of hormone receptors in the tissuesNumber of hormone receptors in the tissues

Magnitude of signal sent to cell nucleus by receptor complexMagnitude of signal sent to cell nucleus by receptor complex

Interaction with cell nucleusInteraction with cell nucleus


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Adaptations Following contAdaptations Following cont Endocrine responses to exercise (figure 9)Endocrine responses to exercise (figure 9)

Biochemical changes seen in skeletal muscle induced byBiochemical changes seen in skeletal muscle induced by

training (list on figure 10)training (list on figure 10) Skeletal adaptations (figure 11)Skeletal adaptations (figure 11)

Bone is connective tissue that becomes mineralized to provide aBone is connective tissue that becomes mineralized to provide arigid structure to support the muscular systemrigid structure to support the muscular system

Bone is an active tissue and is sensitive to gravitational andBone is an active tissue and is sensitive to gravitational and

muscular forcesmuscular forces Bone will adapt with exercise trainingBone will adapt with exercise training

Increase in bone mineral density and bone matrixIncrease in bone mineral density and bone matrix

Decrease in bone density w/ reduction of exerciseDecrease in bone density w/ reduction of exercise

Rapid removal of calcium = loss of bone mineral content; occursRapid removal of calcium = loss of bone mineral content; occurs

with immobilization after only a few weeks of bed restwith immobilization after only a few weeks of bed rest Osteoporosis in elderly; postOsteoporosis in elderly; post--menopausal womenmenopausal women

Resistance training has proven to be effective in increasing bonResistance training has proven to be effective in increasing boneemineral content and bone matrix (figure 12)mineral content and bone matrix (figure 12)


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Adaptations Following contAdaptations Following cont Connective tissue adaptationsConnective tissue adaptations

Related to mechanical forces created during physical activityRelated to mechanical forces created during physical activity

Degree of adaptation related to intensity of the exercise stimulDegree of adaptation related to intensity of the exercise stimulusus

Adaptations occurAdaptations occur At the junctions between the tendon or ligament and the boneAt the junctions between the tendon or ligament and the bone

surfacesurface

Within the body of the tendon or ligamentWithin the body of the tendon or ligament

In the network of fascia within the skeletal muscleIn the network of fascia within the skeletal muscle

Cardiovascular adaptations (figure 13)Cardiovascular adaptations (figure 13) Increase in cardiac output due to an enhanced or improvedIncrease in cardiac output due to an enhanced or improved

stroke volumestroke volume

Increase in heart weight/volume occursIncrease in heart weight/volume occurs primarilyprimarily with aerobicwith aerobictrainingtraining

Cardiac hypertrophy is characterized by an increase in the sizeCardiac hypertrophy is characterized by an increase in the size ofofthe left ventricular cavity and a thickening of the myocardiumthe left ventricular cavity and a thickening of the myocardium


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Adaptations Following contAdaptations Following cont Increase in cardiac outputIncrease in cardiac output

Stroke volume increasesStroke volume increases

Greater percent of the ventricular volume that is pumped out witGreater percent of the ventricular volume that is pumped out withh

each beat (ejection fraction)each beat (ejection fraction) Typical values of ejection fractionTypical values of ejection fraction

Average individualAverage individual65%65%

Aerobically trained athleteAerobically trained athlete8585--90%90%

Individual with cardiovascular diseaseIndividual with cardiovascular disease12%12%

Max heart rate may increase or may even decrease withMax heart rate may increase or may even decrease withexercise trainingexercise training Increase may be related to a learning effectIncrease may be related to a learning effectpossibly neverpossibly never

achieved max heart rate prior to training; can do more exerciseachieved max heart rate prior to training; can do more exercise

Decrease may be related to an increasedDecrease may be related to an increased vagalvagal tonetone

Decreased resting heart rate due to more parasympathetic influenDecreased resting heart rate due to more parasympathetic influen

cece

Decreased heart rate at any givenDecreased heart rate at any given submaximalsubmaximal intensityintensity

IncreasedIncreased capillarizationcapillarization in tissue after trainingin tissue after training

Increased plasma volume and total hemoglobin after trainingIncreased plasma volume and total hemoglobin after training


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Adaptations Following contAdaptations Following cont Respiratory adaptations (figure 13)Respiratory adaptations (figure 13)

Increased maximal exercise ventilationIncreased maximal exercise ventilation Increased maximal oxygen consumption (VO2 max)Increased maximal oxygen consumption (VO2 max)

Increased tidal volumeIncreased tidal volume

Increased extraction of Oxygen (14Increased extraction of Oxygen (14--15% O2 in15% O2 inexpired air after training versus 18% in untrainedexpired air after training versus 18% in untrainedperson)person)

Onset of blood lactate accumulation (OBLA) occurs atOnset of blood lactate accumulation (OBLA) occurs athigher percentage of the trained personhigher percentage of the trained persons aerobics aerobiccapacity (55% untrained vs. up to 90% trained) as acapacity (55% untrained vs. up to 90% trained) as aresult of an increased ability to generate a highresult of an increased ability to generate a highlactate level after traininglactate level after training


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Specific Adaptations fromSpecific Adaptations from

Resistance TrainingResistance Training

Changes in fiber areaChanges in fiber area

Hypertrophy vs. hyperplasia of muscle fibersHypertrophy vs. hyperplasia of muscle fibers

Muscle fiberMuscle fiber transformationtransformationTypeType IIbIIb TypeType

IIaIIa

fibersfibers

Increased high energy phosphate poolIncreased high energy phosphate pool

Improved synchronization of motor unit firingImproved synchronization of motor unit firing

Improved neural functionImproved neural function


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Specific Adaptations from AerobicSpecific Adaptations from Aerobic

TrainingTraining

IncreasedIncreased myoglobinmyoglobin contentcontent

Increased oxidation of carbohydrates (glycogen)Increased oxidation of carbohydrates (glycogen) Increased capacity for muscle to generate energyIncreased capacity for muscle to generate energy

Increased oxygen consumption (VO2) andIncreased oxygen consumption (VO2) and

oxygen extraction (aoxygen extraction (a--vO2 difference)vO2 difference)

Increased biochemical changes in Type I and IIIncreased biochemical changes in Type I and II

muscle fibersmuscle fibers

Increased heart size and efficiencyIncreased heart size and efficiency


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Combination of Resistance andCombination of Resistance and

Aerobic Endurance TrainingAerobic Endurance Training

Combined maximal training interferesCombined maximal training interferesprimarily w/ strength and powerprimarily w/ strength and power

performanceperformance


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OvertrainingOvertraining Markers of anaerobic overtraining (fig. 15)Markers of anaerobic overtraining (fig. 15)

Psychological effects: decreased desire to train; decreased joyPsychological effects: decreased desire to train; decreased joy fromfrom

trainingtraining Acute epinephrine andAcute epinephrine and norepinephrinenorepinephrine increases beyond normalincreases beyond normal

exercise induced levelsexercise induced levels

Performance decrements, although these occur too late to be a goPerformance decrements, although these occur too late to be a goododpredictorpredictor

Markers of aerobic overtraining (fig. 15)Markers of aerobic overtraining (fig. 15) Decreased performanceDecreased performance

Decreased percentage of body fatDecreased percentage of body fat

Decreased maximal oxygen uptakeDecreased maximal oxygen uptake

Decreased muscle glycogenDecreased muscle glycogen

Decreased lactate levelsDecreased lactate levels

Increased muscle sorenessIncreased muscle soreness

Increased subIncreased sub--maximal exercise heart ratemaximal exercise heart rate

Altered blood pressure and resting heart rateAltered blood pressure and resting heart rate


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Overtraining contOvertraining cont Stages of overtraining (figure 16)Stages of overtraining (figure 16)

11stst (no effect on performance)(no effect on performance)

22ndnd (probably no effect on performance)(probably no effect on performance)

33rdrd (probably decreased performance)(probably decreased performance)

44thth (decreased performance)(decreased performance)

metabolic adaptation 2

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