chapter
10
Adaptations to
Aerobic and
Anaerobic Training
Aerobic vs. Anaerobic Training
Aerobic (endurance) training leads to
• improved blood flow, and
• increased capacity of muscle fibers to generate
ATP.
Anaerobic training leads to
• increased muscular strength, and
• increased tolerance for acid–base imbalances
during highly intense effort.
Adaptations to Aerobic Training
.
• Improved submaximal aerobic endurance and VO2max
• Muscular changes in fiber size, blood and oxygen
supply, and efficiency of functioning
• Improved efficiency of energy production
Endurance Training
Muscular Endurance
• Ability of a single muscle or muscle group to
sustain high-intensity, repetitive, or static exercise
that occurs in repeated 1- to 2-minute bursts
• Related to muscular strength and anaerobic
development
Cardiorespiratory Endurance
• Ability of the whole body to sustain prolonged,
rhythmic exercise
• Related to development of the cardiovascular and
respiratory (aerobic) system
Evaluating Cardiorespiratory
Endurance
.
VO2max
• Highest rate of oxygen consumption attainable
during maximal exercise
• Can be increased with endurance training
Oxygen Transport System
• Components of the cardiorespiratory system that
transport O2 to and from active tissues
• Evaluated
with the Fick equation:
.
VO2 = SV  HR  a-vO
2 diff
• Can transport O2 more efficiently with adaptations
that occur with endurance training
.
Changes in VO2max With 12 Months of
Endurance Training
Parameters Affected by Training
•
•
•
•
•
•
•
Heart size
Stroke volume
Heart rate
Cardiac output
Blood flow
Blood pressure
Blood volume
Percentage Differences in Heart Size
Among Three Groups of Athletes
Key Points
Heart Size Adaptations
• The left ventricle changes the most in response to
endurance training.
• The internal dimensions of the left ventricle
increase mostly due to an increase in ventricular
filling.
• The wall thickness of the left ventricle increases,
making the potential contraction of the left ventricle
more forceful.
Changes in Stroke Volume With
Endurance Training
Key Points
Stroke Volume Adaptations
• Endurance training increases SV at rest and during
submaximal and maximal exercise.
• Increases in end-diastolic volume, caused by an
increase in blood plasma and greater diastolic
filling time, contribute to increased SV.
• The increased size of the heart allows the left
ventricle to stretch more and fill with more blood.
Heart Rate During Exercise
Submaximal
• Decreases proportionately with the amount of
training completed
• May decrease by 20 to 40 beats per min after 6
months of moderate training
Maximal
• Remains unchanged or decreases slightly
• Thought to decrease to allow for optimal stroke
volume and maximize cardiac output
Resting Heart Rate
• Decreases with endurance training due to more blood
returning to heart
• In sedentary individuals can decrease by 1 beat per
min per week during initial training
• Highly trained athletes may have resting heart rates of
40 beats per min or less
Changes in Heart Rate With
Endurance Training
Which Comes First?
Does increased stroke volume allow a decreased heart
rate, or does decreased heart rate allow an increased
stroke volume?
Heart Rate Recovery Period
• It is the time after exercise that it takes your heart to
return to its resting rate.
• With training, heart rate returns to resting level more
quickly after exercise.
• Has been used as an index of cardiorespiratory fitness.
• Conditions such as altitude or heat can affect it.
• Should not be used to compare individuals to one
another.
Changes in Heart Rate Recovery With
Endurance Training
Did You Know . . . ?
Resistance training can lead to decreases in heart
rate; however, these decreases are not as reliable or
as large as those that occur as a result of endurance
training.
Key Points
Cardiac
Output Adaptations
.
• Q either doesn’t change at rest or during
submaximal exercise, or it decreases slightly.
• A slight change could be the result of an increase
- difference due to greater oxygen
in the a-vO
2
extraction
by the tissues.
.
• Q increases dramatically at maximal exertion due
to the increase in maximal
SV.
.
• Absolute values of Qmax range from 14 to 20 L/min
in untrained people, 25 to 35 L/min in trained
individuals, and 40 L/min or more in large
endurance athletes.
Changes in Cardiac Output With
Endurance Training
Blood Flow Increases With Training
• Increased capillarization of trained muscles (higher
capillary-to-fiber ratio)
• Greater opening of existing capillaries in trained
muscles
• More effective blood redistribution—blood goes where it
is needed
• Increased blood volume
CAPILLARIZATION IN MUSCLES (>15%)
Untrained
Trained
Key Points
Blood Pressure and Training
• Blood pressure changes little during submaximal or
maximal exercise.
• Resting blood pressure (both systolic and diastolic)
is lowered with endurance training in individuals
with borderline or moderate hypertension.
• Blood pressure during lifting of heavy weights can
cause increases in systolic and diastolic blood
pressure, but resting blood pressure after weight
lifting tends to remain unchanged or decrease.
(continued)
Key Points (continued)
Blood Volume and Training
• Endurance training, especially intense training,
increases blood volume.
• Blood volume increases due to an increase in plasma
volume (increases in ADH, aldosterone, and plasma
proteins cause more fluid to be retained in the blood).
• Red blood cell volume increases, but increase in
plasma volume is higher; thus, hematocrit decreases.
• Blood viscosity decreases, thus improving circulation
and enhancing oxygen delivery.
• Changes in plasma volume
are highly correlated with
.
changes in SV and VO2max.
Increases in Total Blood Volume and
Plasma Volume With Endurance Training
Cardiovascular Adaptations to
Training
•
•
•
•
•
•
•
Left ventricle size and wall thickness increase
Stroke volume increases
Resting and submaximal heart rates decrease
Maximal heart rate stays the same or decreases
Blood volume increases
Blood pressure does not change or slightly decreases
Cardiac output is better distributed to active muscles
Key Points
Respiratory Adaptations to Training
• Static lung volumes remain unchanged; tidal
volume, unchanged at rest and during submaximal
exercise, increases with maximal exertion.
• Respiratory rate stays steady at rest, decreases
with submaximal exercise, and can increase
dramatically with maximal exercise after training.
• Pulmonary ventilation increases during maximal
effort after training.
(continued)
Key Points (continued)
Respiratory Adaptations to Training
• Pulmonary diffusion increases at maximal work
rates.
• The a-vO
2 difference increases with training due to
more oxygen being extracted by tissues.
• The respiratory system is seldom a limiter of
endurance performance.
• All the major adaptations of the respiratory system
to training are most apparent during maximal
exercise.
Muscular Adaptations
• Increased size of type I fibers
• Increased number of capillaries supplying the muscles
• Increased myoglobin content of muscle (allowing
muscle to have more oxygen)
• Increased number, size, and oxidative enzyme activity
of mitochondria
Percentage of Change in the Activity of
SDH and Maximal Oxygen Uptake
Leg Muscle Enzyme Activities of Untrained
(UT) Subjects, Moderately Trained (MT)
Joggers, and Highly Trained (HT) Runners
Adapted, by permission, from D.L. Costill et al., 1979, "Lipid metabolism in skeletal muscle of endurancetrained males and females," Journal of Applied Physiology 28: 251-255 and D.L. Costill et al., 1979,
"Adaptations in skeletal muscle following strength training," Journal of Applied Physiology 46: 96-99.
Adaptations Affecting Energy
Sources
• Trained muscles store more glycogen and
triglycerides than untrained muscles.
• FFAs are better mobilized and more accessible to
trained muscles.
• Muscles’ ability to oxidize fat increases with training.
• Muscles’ reliance on fat stores first conserves
glycogen during prolonged exercise.
MITOCHONDRIA (A), GLYCOGEN (B),
AND TRIGLYCERIDES (C)
Metabolic Adaptations to Training
Lactate threshold increases.
Respiratory exchange ratio
• decreases for submaximal efforts (greater use of
FFAs) and
• increases at maximal levels.
.
Oxygen consumption (VO2) is
• unaltered or slightly increased at rest,
• unaltered or slightly decreased at submaximal
rates of work, and
.
• increases at maximal exertion (VO2max) from 4% to
93% until limited by oxygen delivery.
Changes in Lactate Threshold With
Training
Did You Know . . . ?
Once an athlete has
. achieved her genetically
determined peak VO2max, she can still increase her
endurance performance due to the body’s ability to
perform
at increasingly higher percentages of that
.
VO2max for extended periods. The increase
in
.
performance without an increase in VO2max is a result
of an increase in lactate threshold.
.
Factors Affecting VO2max
Level of conditioning—Max is reached within 8 to 18
months of heavy endurance training.
Heredity—Accounts
for as much as half the variation in
.
VO2max as well as an individual’s response to training.
.
Age—Decreases in VO2max with age might be a result of
age-related decreases in activity levels.
Gender—Lower in women than men (20% to 25% lower
in untrained women; 10% lower in highly trained
women).
Specificity of training—The closer training is to the
sport to be performed, the greater the improvement and
performance in that sport.
Aerobic Endurance and
Performance
• It’s the major defense against fatigue, which limits
optimal performance.
• Should be the primary emphasis of training for health
and fitness.
• All athletes can benefit from maximizing their
endurance.
Key Points
Adaptations to Aerobic Training
• Aerobic training stresses type I fibers more than
type II fibers and causes type I fibers to increase in
size (but not in percentage).
• Prolonged aerobic training may cause type IIb
fibers to take on characteristics of type IIa fibers.
• The number of capillaries supplying each muscle
fiber increases with training.
• Myoglobin (which stores oxygen) content increases
in muscle about 75% to 80% with aerobic training.
(continued)
Key Points (continued)
Adaptations to Aerobic Training
• Aerobic training increases the number and size of
mitochondria and the activities of oxidative
enzymes.
• Endurance-trained muscle stores more glycogen
and triglyceride than untrained muscle.
• Increased fat availability and capacity to oxidize fat
lead to increased use of fat as an energy source,
sparing glycogen.
Aerobic Training Considerations
Volume
• Frequency of exercise bouts
• Duration of each exercise bout
Intensity
• Interval training
• Continuous training
Training Volume
• Volume is the load of training in each training session
and over a given period of time.
• Adaptations to given volumes vary from individual to
individual.
• An ideal aerobic training volume appears to be
equivalent to an energy expenditure of about 5,000 to
6,000 kcal per week.
• Athletes who train with progressively greater workloads
eventually reach a maximal level of improvement
beyond which
. additional. training volume will not
improve endurance or VO2max.
Training Intensity
• Muscular adaptations are specific to the speed as well
as duration of training.
• Athletes who incorporate high-intensity speed training
show more performance improvements than athletes
who perform only long, slow, low-intensity training.
• Aerobic intervals are repeated, fast-paced, brief
exercise bouts followed by short rests.
• Continuous training involves one continuous, highintensity exercise bout.
Change in Race Pace With Continued
Training After Maximal Oxygen Uptake
Stops Increasing
.
Comparisons of VO2max of Twin and
Nontwin Brothers
Adapted, by permission, from C. Bouchard et al., 1986, "Aerobic performance in brothers, dizygotic and monozygotic twins,"
Medicine and Science in Sports and Exercise 18: 639-646.
.Variations in the Percentage Increase in
VO2max for Identical Twins Undergoing the
Same Training Program
From D. Prud'homme et al., 1984, "Sensitivity of maximal aerobic power to training is genotype-dependent," Medicine and
Science in Sports and Exercise 16(5): 489-493. Copyright 1984 by American College of Sports Medicine. Adapted by
permission.
.
Variations in the Improvement in VO2max
Following 20 Weeks of Endurance Training
by Family
Adapted, by permission, from C. Bouchard et al., 1999, "Familial aggregation of VO2max response to exercise training. Results
from HERITAGE Family Study," Journal of Applied Physiology 87: 1003-1008.
Adaptations to Anaerobic Training
•
•
•
•
Increased muscular strength
Slightly increased ATP-PCr and glycolytic enzymes
Improved mechanical efficiency
Increased muscle oxidative capacity (for sprints longer
than 30 s)
• Increased muscle buffering capacity
Did You Know . . . ?
Performance improvements after anaerobic training
(short, high-intensity training) appear to be related
more to muscular strength gains than improvements
in the anaerobic yield of ATP through the ATP-PCr and
glycolytic systems.
Muscle Buffering Capacity
• Anaerobic training improves muscle buffering capacity,
but aerobic training does little to increase the muscles’
capacity to tolerate sprint-type activities.
• Improved muscle buffering capacity allows sprinttrained athletes to generate energy for longer periods
before fatigue limits the contractile process.
Selected Muscle Enzyme Activities
(mmol · g-1 · min–1) for Untrained, Anaerobically
Trained, and Aerobically Trained Men
Aerobic enzymes
Untrained
Oxidative system
Succinate dehydrogenase
8.1
Malate dehydrogenase
45.5
Carnitine palmityl transferase
1.5
Anaerobic enzymes
ATP-PCr system
Creatine kinase
Myokinase
Glycolytic system
Phosphorylase
Phosphofructokinase
Lactate dehydrogenase
aDenotes
Anaerobically
trained
8.0
46.0
1.5
Aerobically
trained
20.8 a
65.5 a
2.3 a
609.0
309.0
702.0
350.0
589.0
297.0
5.3
19.9
766.0
5.8
29.2
811.0
3.7
18.9
621.0
a significant difference from the untrained value.
a
Key Points
Adaptations to Aerobic Training
• Ideal aerobic training volume is equivalent to a
caloric expenditure of 5,000 to 6,000 kcal per
week.
• To perform at higher intensities, athletes must train
at higher intensities.
• Aerobic interval training involves repeated bouts of
short, high-intensity performance followed by short
rest periods; continuous training—one prolonged,
high-intensity bout—also helps generate aerobic
benefits.
(continued)
Key Points (continued)
Adaptations to Anaerobic Training
• Anaerobic training improves anaerobic
performance mostly as a result of strength gains.
• Anaerobic training improves efficiency of
movement and thus reduces the energy expended
for that movement.
• Bouts of anaerobic training lasting beyond 30 s rely
on oxidation for energy; muscle aerobic capacity
can be improved with this type of training.
• Anaerobic training increases muscle buffering
capacity, thus delaying fatigue.
Methods of Monitoring Training
Changes
.
• Repeated measurements of VO2max
• Lactate threshold tests
• Comparing lactate values taken after steady-state
exercise at various times in the training period
Changes in Creatine Kinase (CK) and
Muscle Myokinase (MK) Activities
Performance in a 60 s Sprint Bout After
Training With 6 s and 30 s Anaerobic Bouts
.
VO2max Values During Uphill Treadmill
Running Versus Sport-Specific Activities
Adapted, by permission, from S.B. Stromme, F. Ingjer, and H.D. Meen, 1977, "Assessment of maximal
aerobic power in specifically trained athletes," Journal of Applied Physiology 42: 833-837.