Kines 350 Exam 4: training

what are the principles of exercise training design?

1. training variables

2. specificity

3. overload

4. individuality

5. reversibility

6. variation (periodization)

7. overtraining

what is specificity in regards to training?

training effect is specific to

• muscle fibers recruited

• energy system involved

• force and velocity of contraction

• type of contraction

• type of training dictates adaptation

what is overload?

a system being stressed beyond its normal point for adaptation

• should be progressive

• may be achieved by altering FITT

what is FITT?

• Frequency of training

• Intensity of training

• Time of training

• Type of activity

what is individuality?

adaptations and their rate may vary between individuals

• largely genetic

• program must be specific to individual needs

• every responds given right time + stimulus

what is reversibility?

over time - adaptions will reverse

• endurance: within 2 weeks

• strength: within 3 weeks

a few days would not hurt (tapering)

once a certain level of fitness is achieved ________ is needed to maintain training adaptations

minimum amount of regular exercise

• endurance: 2-3 times / week intensity >70% VO2 max

what would the goal “starting faster” entail?

decrease the O2 deficit

what would the goal an increased endurance time entail?

increase lipolysis and spare glycogen

_____ is smaller in endurance training

O2 deficit

• less PCr depletion

• less lactate accumulation

how would an increase in VO2 max impact performance?

greater endurance performance and capacity

what are the suggested trainings to increase VO2 max

large muscle groups, dynamic activity

• 20-60 min >3 times a week (>50% VO2max)

• 6 weeks or more

who would expect a greater increase in VO2 max with training, those with high initial VO2 max or those with low?

low (up to 50% increase)

• training intensity of 40-50% VO2max

how much do genetics determine the VO2 response to training

about 50%

• Polymorphisms in 21 genes account for 47% of the change in VO2 max in white men

• Heart size and lipid metabolism also matter

• predisposition for exceptional VO2 max

why does VO2 improve with training?

central adaptations: enhance blood and oxygen delivery

• larger blood volume

• larger stroke volume and cardiac output

peripheral adaptations: increase oxygen extraction

• increased oxidative capacity

• increased blood supply within muscle

how is VO2 max solved?

HR max X SV max X O2(a-v) max

why are longitudinal studies better than cross-sectional for VO2 max improvement, what do they show?

cross sectional: differences primarily because of SV differences

longitudinal: reveal exercise-induced improvements in extraction of O2

• short duration: notable increase in VO2 max, small increase in SV, smallest increase in O2 extraction

• long duration: moderate increase in Vo2max, small increase in SV, notable increase O2 extraction

What are the cardiac output changes due to endurance exercise?

• no change is resting CO

• 10-20% increase in CO during maximal exercise

• unchanged at rest and submaximal exercise

what are the adaptations to HR due to endurance exercise?

• decreased HR at rest and fixed rates of submax work (↑ PNS, ↓ below intrinsic HR)

• no change/ slight ↓ in maximal HR

• faster HR recovery following exercise

• same HR at same VO2max

what are the adaptations to SV due to endurance exercise training?

greater SV at rest, submax, and maximal exercise

• reflects cardiac hypertrophy

• maintains CO with lower HR

  • contributes to greater max CO

why does maximal SV increase due to endurance training?

↑ Preload (EDV)

• ↑ plasma volume, ↑ venous return, ↑ ventricular volume

↓ Afterload (SVR)

• ↓ arterial constriction

• ↑ capillaries

• ↑ maximal muscle blood flow with no change in MAP

↑ Contractility

what rapid changes (within 6 days) occur from training?

• 11% ↑ in plasma volume

• 7% ↑ VO2max

• 10% ↑ in SV

what remodeling occurs in the heart with training

↑ heart size

• chamber (endurance)

• wall thickness (strength)

• pericardial size

endurance training adaptations of O2 extraction

• unchanged at rest and submaximal

• ↑ oxygen extraction during maximal (very long time…months/years)

how does an ↑ O2 extraction impact a-v O2 difference?

increases the difference

• CvO2 max drops to 2-3 ml/100ml blood in trained athletes

why does O2 extraction increase with training?

• ↑ muscle blood flow (decrease SNS)

• ↑ capillary density (recruitment + better BF distribution)

• ↑ mitochondria number

what occurs 2-3 weeks of detraining

• decrease SV (10%)

• decrease Q (10%)

• decrease VO2 max (~5-10%)

• longer term decreased O2 (a-v)

what is the goal of cardiac rehab?

minimizing the changes from detraining

what are the adaptations to blood from training?

• ↑ total blood volume (10-30%)

  • ↑ plasma volume, ↑ RBC mass (0-10%)

• ↓ Hct

• ↓ blood pressure (with endurance training)

training ____ the submaximal ventilatory response to exercise

reduces

what is the endurance trained phenotype?

• improves the ability to exercise at the same intensity

• more rapid transition rest-steady state

• reduced reliance on glycogen

• cardiovascular/thermoregulatory adaptations increase BF and O2 delivery

• neural and hormonal adaptations

• biomchemical changes to muscle

what are the net results of training?

• increase VO2max of muscle

• ↓ O2 deficit (by increasing rate of increase in VO2 at exercise onset)

what are the responses that improved oxygen extraction

1. mitochondrial

• increases in amount of mitochondria

• (size has larger effect than number)

2. capillary supply

• angiogenesis

• affects substrate delivery and waste removal

  • per fiber (15%)

  • per unit area (30%)

3. myoglobin content

• muscle form of O2 storage, ~80% increase

4. Muscle fiber type

• Endurance activities rely mostly on ST fibers

• training: small increase in fiber size, shift from faster fibers to slower (FG to FOG, FOG to SO)

5. enzymatic activity

• all fiber types show an increase in enzymes of glycolysis, beta oxidation, and oxidative system

endurance training _____ mitochondrial volume and turnover

increases

what are the muscle fiber mitochondria, what are their differences?

• subsarcolemmal - 20%, larger and faster turnover

• intermyofibrillar - 80% more abundance, greater ATP synthesis

what are the mitochondrial changes seen with endurance training?

mitochondrial content (biogenesis) increases quickly

• depends on intensity/duration of training

• can increase 50-100%

improved bioenergetics

• decrease glucose utilization

• increase fat metabolism

• faster ADP uptake (spares PCr, tempers glycolysis, less lactate and H+ formation)

increased mitochondrial turnover in muscle

• faster removal of damaged mitochondria

how do mitochondria response to training/detraining?

• half-time response within 1 week

• 99% of responses occur in about 6 weeks

• same response with detraining (50% loss within one week)

  • majority lost within 2 weeks

one week of detraining requires _____ of retraining to regain mitochondrial adaptations

3-4 weeks

when the mitochondrial training response drops, why does VO2 responses not follow?

because the heart is the limiting factor, there are still exercise adaptations to the heart for longer

exercise is the most potent stimulator of _______ in skeletal muscle

angiogenesis

• 10-30% increase after 6-8 weeks (up to 200% in highly trained)

what are the benefits of angiogenesis?

• greater diffusion of oxygen: slower RBC transit time, increased O2(a-v)

• faster rise in VO2 at the start of exercise

• increased removal of wastes

how does endurance training impact oxygen carriers?

• total amount of hemoglobin mass and muscle myoglobin

• partial pressure and concentration change little

• allows for more O2 delivered to mitochondria

how are muscle fibers adapted due to training?

muscle fiber type conversion: fast to slow

• FG fiber prevalence decreases

• FOG/IIa fiber prevalence and cross-sectional

• SO/I fibers may increase as well

in response to training: muscles are becoming slower and more oxidative

how are muscle fibers adapted due to detraining?

conversion slow to fast

• for both fibers, peak force and power reduced

• large (30%) and variable decreases in type I cross sectional area, peak force, and velocity

• smaller decrease in type II number, area and velocity

how does endurance exercise impact oxidative enzymes?

Citrate synthase: biomarker of oxidative capacity

• intensity:

  • increased CS activity with all intensities

  • independent of intensity in IIa fibers

• duration:

  • increased CS activity independent of duration in IIa fibers

  • increase in CS activity in IIx fibers with higher intensity, longer duration training

what are the overall muscle changes to endurance training?

• reduction in O2 deficit

• increased oxygen extraction

• change in muscle fiber type

• increased capillary density

• increased myoglobin content

• increased mitochondrial content

• increased oxidative enzyme activity

how are bioenergetic systems adapted by endurance training?

lactate threshold occurs at higher work rate (untrained: 50-65% VO2max, trained: 70-85% VO2max)

• ability to maintain higher exercise intensity before fatiguing

• faster race pace

how is glycogen availability adapted by endurance training?

increased muscle and liver stores

• greater CHO availability delays fatigue

how is the use of lipids adapted by endurance training?

adipose tissue:

• increased sensitivity of HSL to catecholamines (lipolysis elevated)

• higher pH, less suppression of FA mobilization

muscle:

• IM lipid droplets smaller

• increased amount of adipose triglyceride lipase (ATGL) - greater IM lipid turnover

greater use of fat, sparing glycogen

how does endurance training adapt fuel utilization?

increased utilization of fate, spares plasma glucose + muscle glycogen

transport of FFA into muscle

• increased capillary density

• increased FA binding protein and FA transclocase

transport FFA from cytoplasm to mitochondria

• increased mitochondrial content

mitochondrial oxidation of FFA

• increased enzymes of beta oxidation (increased acetyl-CoA formation, high citrate lvl inhibits PFK and glycolysis)

how is the acid-base balanced adapted due to endurance training?