nsca cscs chapter 20 — program design and technique for aerobic endurance training

nsca cscs chapter 20 — program design and technique for aerobic endurance training

Designing an aerobic training program has many similarities
to anaerobic exercise prescription. This chapter
discusses the general principles of program design as
they apply to aerobic endurance training and a stepwise
approach to designing a safe and effective program.
Improvements in aerobic endurance performance
can be derived only when sound principles are applied
during training. Although the fundamental mechanisms
responsible for inducing adaptations during training are
undefined, it is clear that in order to adapt, the various
systems of the body must be challenged by an exercise
stimulus (e.g., specificity and overload). The physiological
systems that are not involved during the training
session or not stressed sufficiently by exercise will not
adapt to the training program (47, 48).
Training specificity refers to the distinct adaptations
to the physiological systems that arise from the training
program. A training effect is limited to the physiological
systems used and overloaded during training (48, 73).
Unless training programs are strictly designed to involve
and stress a physiological system, there will be very limited
or possibly no adaptations in that system. To improve
aerobic endurance performance, training programs must
be designed to enhance the function of the respiratory,
cardiovascular, and musculoskeletal systems.
For a training adaptation to occur, a physiological
system must be exercised at a level beyond that to
which it is presently accustomed (72). During continued
overload, the physiological systems of the body adapt to
the exercise stress. Adaptations within the physiological
systems occur until the tissues are no longer overloaded.
This necessitates use of a greater overload. Exercise
frequency, duration, and intensity are the variables most
often manipulated to provide overload to the systems
of the body.
Successful performance in aerobic endurance competitions
involving running, cycling, and swimming is
dependent on the athlete’s ability to cover a fixed distance
in the shortest time possible. This requires athletes
to be in peak physical condition for the competition.
To reach this level of performance, athletes must train
hard, yet intelligently, to maximize the physiological
adaptations derived from training. In fact, the physical
condition of the aerobic endurance athlete is of primary
importance if that athlete is to perform at optimal levels
during competition (15, 24, 54, 77, 82). A common
trend with many aerobic endurance athletes is to adopt
and embrace the training practices of other highly
successful or well-known aerobic endurance athletes.
Although this strategy may be effective for a few, most
aerobic endurance athletes would likely be better served
by constructing their own training regimen based on a
good working knowledge of sound training principles
and an understanding of their own physical limitations
and needs.
Numerous types of training programs have been
designed for aerobic endurance athletes. These training
programs vary in the mode, frequency, duration,
and intensity of the activity. What successful aerobic
endurance athletes have in common is a training program
designed to enhance their strengths and improve
their weaknesses. This chapter is designed to provide
the strength and conditioning professional with a good
working knowledge of the scientific principles of aerobic
endurance training and conditioning. Specifically, the
chapter includes information about the factors related to
performance, aerobic endurance training program design
variables, and the various types of programs. Additional
discussion focuses on sport season training and special
issues related to aerobic endurance training. As it would
be exhausting to review relevant information about
training for all possible aerobic endurance sports, only
basic aerobic endurance training topics are presented,
with specific examples as they relate to running, cycling,
and swimming.
Factors Related to Aerobic
Endurance Performance
When designing aerobic endurance training programs,
it is important to understand those factors that influence
and play a significant role in successful aerobic endurance
performance. This allows for the development of
sound training programs while minimizing unnecessary
training that may lead to counterproductive adaptations,
fatigue, overwork, or overtraining.
Maximal Aerobic Capacity
As the duration of the aerobic endurance event increases,
so does the proportion of the total energy demand that
must be met by aerobic metabolism. Therefore, high
maximal aerobic capacity (V
.
O2max) is necessary
for success in aerobic endurance events (59). A high
correlation has been shown to exist between V
.
O2max
and performance in aerobic endurance events (1, 19,
32, 59, 60). Consequently, aerobic endurance training
programs should be designed to improve V
.
O2max.
However, although a high V
.
O2max is important for
successful performance, other factors may be equally or
even more important. These factors include a high lactate
threshold, good exercise economy, high efficiency
in using fat as a fuel source, and a high percentage of
Type I muscle fibers.
For well-trained endurance athletes, improving
V .
O2max may benefit performance only up to a certain
point, especially since these individuals typically already
possess excellent aerobic capacity. Consequently, the
ability to sustain higher velocities during competition
and training may have a greater impact on performance
than attempting to make marginal improvements in aerobic
capacity. For this reason, many athletes use high-intensity
interval training (HIIT). While the issue is not
well understood, HIIT may contribute to performance
in highly trained endurance athletes via improvements
in peak power output, ventilatory threshold, hydrogen
ion buffering, and utilization of fat as a fuel source (55).
Lactate Threshold
In aerobic endurance events, the best competitor among
athletes with similar V
.
O2max values is typically the
person who can sustain aerobic energy production at the
highest percentage of his or her V
.
O2max without accumulating
large amounts of lactic acid in the muscle and
blood (54). Although numerous terms have been used to
refer to this phenomenon, lactate threshold is the one
most commonly employed in the literature. The lactate
threshold is that speed of movement or percentage of
V .
O2max at which a specific blood lactate concentration
is observed or the point at which blood lactate concentration
begins to increase above resting levels (82). Several
studies have shown that an athlete’s lactate threshold
appears to be a better indicator of his or her aerobic
endurance performance than V
.
O2max (21, 22). The
maximal lactate steady state is another term that often
appears in the aerobic endurance training literature. The
maximal lactate steady state is defined as the exercise
intensity at which maximal lactate production is equal
to maximal lactate clearance within the body (4). The
maximal lactate steady state is considered by many to
be a better indicator of aerobic endurance performance
than either V
.
O2max or the lactate threshold (4, 34). What
is clear from this information is that aerobic endurance
athletes must improve their lactate threshold or maximal
lactate steady state. This requires athletes to conduct
some training at elevated levels of blood and muscle
lactate to maximize training improvements.
Exercise Economy
A measure of the energy cost of activity at a given
exercise velocity is referred to as the exercise economy.
Athletes with a high exercise economy expend
less energy during exercise to maintain a given exercise
velocity (e.g., running speed). Several investigators have
suggested that exercise economy is an important factor
in successful performance in running events (14, 31),
with better performers having a slightly shorter stride
length and greater stride frequency compared to less
successful performers (12). During cycling, exercise
economy can be affected by body mass size, cycling
velocity, and aerodynamic positioning (22, 61, 78). For
cyclists, an increase in body mass and cycling velocity
and an inefficient body position generate greater wind
resistance, resulting in a decrease in exercise economy.
It has been demonstrated that elite swimmers are much
more economical than nonelite swimmers (81) and use
less oxygen at any given swimming velocity. The most
profound impact on exercise economy during swimming
can be observed when swimming technique becomes
more efficient. As improvements in stroke mechanics
occur, energy demand for a given swimming velocity
is reduced (80). Training to improve exercise economy
is critical for aerobic endurance athletes.
?? An improvement in exercise economy can
enhance maximal aerobic capacity (V
.
O2max)
and lactate threshold.
Designing an Aerobic
Endurance Program
An effective aerobic endurance training program must
include an exercise prescription specifically developed
for the individual athlete. This requires manipulation
of the primary program design variables. The sidebar
lists the design variables as steps 1 through 5. Unfortunately,
coaches and athletes often use the training
practices or programs of current successful coaches or
athletes in their sport. This does not carefully consider
the strengths and weaknesses of the athlete and may lead
to development of an ineffective or potentially harmful
training program. The optimal way to develop a sound
training program is to have the factors related to aerobic
endurance performance evaluated and then use that
information to generate a training program specific to
the athlete. For example, an athlete with poor exercise
economy should place emphasis on training to improve
exercise economy. This might include interval training
with a focus on technique, as well as using long rest
periods. Conversely, athletes who need to increase lactate
threshold might consider performing more high-intensity
training.
Training programs for female athletes do not have
to be different from those used to train male athletes;
evidence indicates that males and females respond similarly
to training programs (10, 60, 67). Refer to chapter
7 for a discussion on sex-related differences and their
implications for exercise.
Step 1: Exercise Mode
Exercise mode refers to the specific activity performed
by the athlete: cycling, running, swimming, and so on.
When training to improve aerobic endurance performance,
the athlete should select activities that mimic
as closely as possible the movement pattern employed
in competition. This will cause positive adaptations in
specific physiological systems of the body. For example,
the recruitment of specific muscle fibers and the adaptation
of the energy systems within those fibers must be
challenged during aerobic endurance training. Selecting
the appropriate exercise mode during training ensures
that the systems used in competition are challenged to
improve. Remember that the more specific the training
mode is to the sport, the greater the improvement in
performance. For an athlete involved in multiple aerobic
endurance sports, or one who is interested in a general
aerobic endurance fitness program, cross-training or
participation in multiple aerobic endurance activities
may be warranted (35).
Step 2: Training Frequency
Training frequency refers to the number of training
sessions conducted per day or per week. The frequency
of training sessions depends on an interaction of exercise
intensity and duration, the training status of the athlete,
and the specific sport season. Higher exercise intensity
and longer duration may necessitate less frequent training
to allow sufficient recovery from exercise sessions.
The training status of the athlete can influence training
frequency, with lesser-trained athletes requiring more
recovery days at the beginning of a training period than
more highly trained athletes. The sport season that the
athlete is currently in can also influence training frequency;
an off-season program may include five training
days per week, but training frequency may progress to
daily workouts (or even multiple workouts per day for a
triathlete) in the preseason. Additionally, fewer training
sessions may be required to maintain an achieved level
of physiological function or performance than to attain
that level initially (77). Appropriate training frequency is
important for the aerobic endurance athlete, because too
much training may increase the risk of injury, illness, or
overtraining. A number of studies have shown increased
injury rates with training sessions more frequent than
five times per week (49, 69); however, these studies
used active individuals in a wide age range, not only
young and healthy athletes, as subjects. Conversely, too
little training will not result in positive adaptations to the
various systems of the body. Research has shown that it
is necessary to train more than twice per week in order
to increase V
.
O2max (38, 83). Many coaches recognize
that multiple training sessions per day may be needed
to improve performance in some endurance athletes.
Research conducted by Hansen and colleagues (43)
showed that time to exhaustion, resting muscle glycogen
concentrations, and citrate synthase activity increased
among seven healthy untrained men after 10 weeks of
training twice every other day versus once daily. It was
speculated that training in a glycogen-depleted state may
improve glycogen resynthesis via an increase in the transcription
and transcription rate of certain genes responsible
for training adaptations. However, the researchers
cautioned that these results should not necessarily be
used by coaches and practitioners to guide practice, as
low glycogen concentrations may reduce the period of
time an athlete is able to train and may increase risk of
overtraining. This is one reason why it is important to
monitor the effects of the training load on athletes.
Recovery from individual training sessions is essential
if the athlete is to derive maximum benefits from
the subsequent training session. Exercise performance
has been shown to improve following relative rest from
difficult training sessions (2). Obtaining sufficient rest,
becoming rehydrated, and restoring fuel sources are critical
issues for the athlete during recovery. Relaxation and
avoidance of strenuous physical activity are particularly
important following days of high-intensity or long-duration
training. Postexercise ingestion of adequate fluids
is important for replacing the fluid lost during training.
If the training session was especially long or intense,
then postexercise carbohydrate intake is important for
replacing the muscle and liver glycogen stores that were
likely depleted. More detailed information on this topic
can be found in chapter 10, “Nutrition Strategies for
Maximizing Performance.”
Step 3: Training Intensity
Central to causing training adaptations in the body is the
interaction of training intensity and duration. Generally,
the higher the exercise intensity, the shorter the exercise
duration. Adaptations in the body are specific to the
intensity, or effort expended during a training session.
High-intensity aerobic exercise increases cardiovascular
and respiratory function and allows for improved oxygen
delivery to the working muscles (72). Increasing exercise
intensity may also benefit skeletal muscle adaptations
by affecting muscle fiber recruitment (28). As exercise
intensity is increased, greater recruitment of Type II
muscle fibers occurs to meet the increased power needs.
This training stimulus allows those fibers to become
more aerobically trained, thereby possibly improving
overall aerobic performance.
The regulation of exercise intensity is critical to the
success of each training session and ultimately the entire
program. An exercise intensity that is too low does not
overload the body’s systems and induce the desired
physiological adaptations, whereas an intensity that is
too high results in fatigue and a premature end to the
training session (70). In either instance, the training
session will be poor and ineffective.
The most accurate methods for regulating exercise
intensity are to monitor oxygen consumption during
exercise to determine its percentage of V
.
O2max and to
periodically measure the blood lactate concentration
to determine the relationship to the lactate threshold.
If V
.
O2max testing is not available, exercise prescriptions
can use heart rate, ratings of perceived exertion,
metabolic equivalents, or exercise velocity to monitor
exercise intensity. Cycling power–measuring devices are
frequently used by professional and top-level amateur
competitors.
Heart Rate
Heart rate is likely the most frequently used method
for prescribing aerobic exercise intensity. The reason
is the close relationship between heart rate and oxygen
consumption, especially when the intensity is between
50% and 90% of functional capacity (V
.
O2max), also
called heart rate reserve (HRR), which is the difference
between an athlete’s maximal heart rate and his
or her resting heart rate (5).The most accurate means
of regulating intensity using this method is to determine
the specific heart rate associated with the desired
percentage of V
.
O2max or the heart rate associated with
the lactate threshold. For the greatest precision, this
necessitates laboratory testing to identify these exercise
intensities. If laboratory testing is unavailable, then the
individual’s age-predicted (estimated) maximal heart
rate (APMHR) can be used as the basis for determining
exercise intensity. Refer to the sidebar “Target Heart Rate
Calculations” for formulas and sample calculations for
determining aerobic endurance exercise heart rate ranges
using the Karvonen method and the percentage of
maximal heart rate (MHR) method. The relationship
between V
.
O2max, HRR, and MHR is shown in table
20.1.
Although the Karvonen and percentage of maximal
heart rate formulas provide practical intensity assignments,
basing them on age-predicted maximal heart
rates may entail some inaccuracies (vs. laboratory-tested
maximal heart rates) when exercise intensity is being
monitored during cycling or running (65). It has been
determined that age contributes 75% of the variability
of heart rate; the effects of other factors such as mode
of exercise and fitness level must also be considered
with the use of heart rate to monitor intensity (65).
Additionally, using estimations of exercise intensity
via estimated maximal heart rate equations provides no
information about the intensity associated with the lactate
threshold. Without some knowledge of an athlete’s
lactate threshold, a highly effective aerobic endurance
training program cannot be developed.
Ratings of Perceived Exertion Scales
Ratings of perceived exertion (RPE) scales can also
be used to regulate intensity during aerobic endurance
training (26, 39). It appears that RPE can be used to
accurately regulate intensity when there are changes in
fitness level (6); however, researchers have demonstrated
that the RPE–intensity relationship can be influenced by
various external environmental factors such as passive
distracters and environmental temperature (13, 71).
According to Haddad, Padula, and Chamari (41), various
subject characteristics such as age, sex, training status,
and fitness level may influence RPE. Furthermore, a
few environmental factors that may influence RPE are
listening to music, watching television or video, environmental
temperature, altitude, nutritional considerations,
and external feedback. However, these authors suggest
that despite the potential influence of these factors, RPE
is still a valid monitoring tool (see table 20.2).
Metabolic Equivalents
Metabolic equivalents may also be used to prescribe
exercise intensity. One metabolic equivalent (MET)
is equal to 3.5 ml·kg-1·min-1 of oxygen consumption
and is considered the amount of oxygen required by the
body at rest (1). Metabolic equivalent values have been
determined for a variety of physical activities; a brief list
is shown in table 20.3. For example, an activity with a
MET value of 10.0 requires 10 times the oxygen uptake
that is required by an individual at rest. Assigning MET
values as part of an aerobic exercise prescription requires
the strength and conditioning professional to know (or
estimate) an athlete’s maximal oxygen uptake in order
to be able to calculate an exercise MET level (40).
Power Measurement
Cyclists may use power-measuring cranks and hubs
to monitor exercise intensity (25). Due to cost, these
devices are probably suitable only for professionals
and top-level amateurs. Research studies have indicated
that at least two of these devices provide valid and
reliable power measures (36, 57). Using power to monitor
intensity in cycling has an advantage over other
measures because metabolic rate is closely related to
mechanical power production (25). Using power as an
intensity measure also allows reproducible intensity
efforts regardless of environmental conditions, which
may influence other measurements of intensity such as
heart rate and training velocity (25).
Step 4: Exercise Duration
Exercise duration refers to the length of time of the
training session. The duration of a training session is
often influenced by the exercise intensity: the longer the
exercise duration, the lower the exercise intensity (74).
For example, exercise that is conducted at an intensity
above the maximal lactate steady state (e.g., 85% of
V .
O2max) will have a relatively short duration (20–30
minutes) because the accumulation of lactate within the
muscle will contribute to fatigue. Conversely, exercise
that is performed at a much lower intensity (e.g., 70%
of V
.
O2max) may be performed for several hours before
the athlete experiences fatigue.
?? The duration of a training session is often
influenced by the exercise intensity; the
longer the exercise duration, the lower the
exercise intensity.
Step 5: Exercise Progression
Once athletes begin an aerobic endurance exercise
program, they need to continue the program to either
maintain or advance their aerobic fitness level. Research
seems to indicate that aerobic fitness does not decrease
for up to five weeks when intensity of training is maintained
and frequency decreases to as few as two times
per week (46).
Depending on the goals of the athlete, progression of
an aerobic endurance exercise program initially involves
increasing the frequency, intensity, and duration of
exercise. General recommendations are that individuals
always include at least one recovery or active rest day
in each week of training. Most athletes have the goal of
attempting to increase rather than just maintain aerobic
fitness. This requires regular progression of the training
program. Typically, exercise frequency, intensity, or
duration should not increase more than 10% each week
(42). At higher levels of fitness, athletes will reach a
point where it is not feasible to increase either the frequency
or the duration of exercise. When this occurs,
progressions in training will occur only through exercise
intensity manipulation (42).
As shown by the sidebar titled “Examples of Aerobic
Exercise Progression,” athletes and strength and conditioning
professionals can manipulate combinations
of frequency, intensity, and duration. Progression of
training frequency may be limited by constraints such as
school and work. It may not be possible for the athlete
to incorporate more than one training session each day.
Training intensity measurement should use the same
methods as used in the original exercise intensity prescription.
The best method is determined by the equipment
available to monitor intensity (heart rate monitor,
RPE charts, or machines that provide MET workloads).
Progression of training intensity should be monitored
very carefully to avoid overtraining. The duration of
each training session is limited by the same constraints
as training frequency. Athletes who train predominantly
outdoors are also limited by the number of daylight
hours, especially in the late fall, winter, and early spring.
Types of Aerobic Endurance
Training Programs
There are several types of aerobic endurance training
programs, each with varying frequency, intensity, duration,
and progression parameters. Each type incorporates
the five design variables and results in regimens created
for specific outcomes. Table 20.4 summarizes the types
of aerobic endurance training and their common prescriptive
guidelines. Sample training programs for each
type of aerobic endurance training are included after the
sections that follow; the specific training mode being
discussed is boldfaced in the sample training chart.
Long, Slow Distance Training
Traditionally, endurance coaches and athletes have used
the term long, slow distance (LSD) to refer to training at
intensities equivalent to approximately 70% of V
.
O2max
(or about 80% of maximum heart rate). The fitness
professional and athlete should remember that the term
slow refers to a pace that is slower than typical race pace.
The LSD terminology is probably due for a change to
better reflect the intention of the activity. We have kept
the term LSD to match terminology that is commonly
used. In a LSD training session, the training distance
should be greater than race distance, or the duration
should be at least as long as 30 minutes to 2 hours (24).
This intensity and duration is typically characterized
as “conversation” exercise, with the athlete able to talk
without undue respiratory distress. The physiological
benefits derived from LSD training primarily include
enhanced cardiovascular and thermoregulatory function,
improved mitochondrial energy production and oxidative
capacity of skeletal muscle, and increased utilization
of fat as a fuel (7, 11, 16, 18, 28, 33, 40, 47, 48, 52, 73,
82). These changes are likely to improve the lactate
threshold intensity by enhancing the body’s ability to
clear lactate. Chronic use of this type of training also
causes a change in the metabolic characteristics of the
involved muscles (40, 50) and an eventual shift of Type
IIx fibers to Type I fibers (68, 76).
The increase in fat utilization may also cause a sparing
of muscle glycogen (20, 23, 44, 48, 52, 58, 82). The
intensity during LSD training is lower than the intensity
used during competition, and this may be a disadvantage
if too much of this type of training is performed. Additionally,
LSD training does not stimulate the neurological
patterns of muscle fiber recruitment that are required
during a race (82), and this may result in adaptations
in muscle fibers that are not used during competition.
Pace/Tempo Training
Pace/tempo training employs an intensity at or slightly
higher than race competition intensity. The intensity
corresponds to the lactate threshold; therefore, this type
of training is also often called threshold training (24)
or aerobic–anaerobic interval training (15). There are
two ways to conduct pace/tempo training: steady and
intermittent (24). Steady pace/tempo training is continuous
training conducted at an intensity equal to the
lactate threshold for durations of approximately 20 to 30
minutes. The purpose of pace/tempo training is to stress
the athlete at a specific intensity and improve energy
production from both aerobic and anaerobic metabolism.
Intermittent pace/tempo training is also referred to as
tempo intervals, cruise intervals, or threshold training
(24). During intermittent pace/tempo training, the
intensity is the same as for a steady-threshold workout,
but the training session consists of a series of shorter
intervals with brief recovery periods between work
intervals. During pace/tempo training, it is important to
avoid exercising at a higher intensity than the prescribed
pace. If the workout seems relatively easy, it is better to
increase the distance than to increase the intensity. The
primary objective for this type of training is to develop a
sense of race pace and enhance the body systems’ ability
to sustain exercise at that pace. Pace/tempo training
involves the same pattern of muscle fiber recruitment
as is required in competition. The benefits derived from
this type of training include improved running economy
and increased lactate threshold.
Interval Training
Interval training involves exercise at intensities close to
V .
O2max. The work intervals should last between 3 and
5 minutes, although they can be as short as 30 seconds
(1). The rest intervals for 3- to 5-minute work intervals
should be equal to the work interval, thereby keeping
the work:rest ratio (W:R) at 1:1. Interval training permits
the athlete to train at intensities close to V
.
O2max for a
greater amount of time than would be possible in a single
exercise session at a continuous high intensity. This type
of training should not be performed until a firm base of
aerobic endurance training has been attained (54). Interval
training is very stressful on the athlete and should
be used sparingly. The benefits derived from interval
training include an increased V
.
O2max and enhanced
anaerobic metabolism.
High-Intensity Interval Training
High-intensity interval training, or HIIT, is a form of
training that uses repeated high-intensity exercise bouts
interspersed with brief recovery periods (9). According
to Buchheit and Laursen (9), for an optimal stimulus it
is necessary for athletes to spend several minutes within
the HIIT session above 90% of the V
.
O2max. Both short
(<45 seconds) and long (2- to 4-minute) HIIT intervals
can be used to elicit different training responses. As the
work duration for a single exercise bout is increased, the
energy contribution from anaerobic glycolysis will likely
increase along with blood lactate levels. Additionally,
HIIT training may be beneficial for improving running
speed and economy. This may be particularly important
toward the later stages of an aerobic endurance race when
the “final kick” or “push” is needed to pass a competitor
or set a record or personal best time.
In performing HIIT, the appropriate amount of rest
between repetitions is critical. If the relief intervals are
too short, the athlete will be unable to put forth a quality
effort on subsequent exercise bouts and also will be at
a greater risk for injury. If the rest periods are too long,
many of the benefits experienced from challenging the
anaerobic glycolytic energy system will likely diminish.
An example of an appropriate work-to-rest ratio for
long-interval HIIT training is =2 to 3 minutes at or above
90% V
.
O2max, with relief bouts of =2 minutes (8, 9, 55).
Fartlek Training
Fartlek training (the word Fartlek originates from the
Swedish term for speed play) is a combination of several
of the previously mentioned types of training. Although
Fartlek training is generally associated with running, it
can also be used for cycling and swimming. A sample
Fartlek run involves easy running (~70% V
.
O2max) combined
with either hill work or short, fast bursts of running
(~85–90% V
.
O2max) for short time periods. Athletes can
apply this basic format to cycling and swimming by
simply combining long, slow distance training, pace/
tempo training, and interval training. A Fartlek training
workout challenges all systems of the body and may
help reduce the boredom and monotony associated with
daily training. This type of training is likely to enhance
V .
O2max, increase the lactate threshold, and improve
running economy and fuel utilization.
The various types of training induce different
physiological responses. Ideally a sound program
would incorporate all types of training
into the athlete’s weekly, monthly, or yearly
training schedule.
Application of Program Design
to Training Seasons
The program design variables and the various types
of aerobic endurance training are often applied to athletes’
sport seasons to create a yearly training program.
Typically, the training year is divided into phases that
include the off-season (sometimes called base training),
preseason, in-season (sport competition), and postseason
(active rest). Table 20.5 summarizes the main objectives
and the typical program design assignments for each
training season.
Off-Season (Base Training)
The priority in off-season training is to develop a base of
cardiorespiratory fitness. Initially, the training program
should be composed of long-duration and low-intensity
workouts. As the off-season continues, intensity and,
to a lesser extent, duration are increased; however, the
increase in training duration should not be more than
5% to 10% per week (87). Increasing the training duration
too much can actually lead to decreases in aerobic
endurance performance (18). Periodic increases in
exercise intensity occur when an athlete has adapted to
the training stimulus and requires additional overload
for continued improvements.
Preseason
During the preseason, the athlete should focus on
increasing intensity, maintaining or reducing duration,
and incorporating all types of training into the program.
The strengths and weaknesses of the individual athlete
should determine the amount and frequency of each
type of training.
In-Season (Competition)
The in-season training program needs to be designed
to include competition or race days in the training schedule.
Low-intensity and short-duration training
days should precede scheduled competitions so that
the athlete is fully recovered and rested. The types of
training employed during the in-season are based on the
continued goal of improving weaknesses and maintaining
strengths of the athlete.
Postseason (Active Rest)
During the postseason, the main focus should be on
recovering from the previous competitive season. Low
training duration and intensity are typical for this active
rest phase, but enough overall exercise or activity should
be performed to maintain a sufficient level of cardiorespiratory
fitness, muscular strength, and lean body mass.
During the postseason, the aerobic endurance athlete
should focus on rehabilitating injuries incurred during
the competitive season and improving the strength of
weak or underconditioned muscle groups.
?? A sound year-round aerobic endurance training
program should be divided into sport
seasons with specific goals and objectives
designed to improve performance gradually
and progressively.
Special Issues Related
to Aerobic Endurance Training
In addition to the program design variables, it is important
to consider other related issues when developing
an aerobic endurance training program. These include
cross-training, detraining, tapering, and supplemental
resistance training. The strength and conditioning professional
should contemplate these issues when adapting
the types of aerobic endurance training programs to an
individual athlete or developing an aerobic endurance
program based on the sport season.
Table 20.5 Sport Season Objectives and Program Design Assignments
Sport season Objective
Frequency
per week Duration Intensity
Off-season
(base training)
Develop sound conditioning base 5–6 Long Low to moderate
Preseason Improve factors important to
aerobic endurance performance
6–7 Moderate to long Moderate to high
In-season
(competition)
Maintain factors important to
aerobic endurance performance
5–6 (training and
racing)
Short (training) Low (training)
Race distance High (racing)
Postseason
(active rest)
Recovery from competitive
season
3–5 Short Low
Data from references 15, 24, 54, 77, and 82.
Cross-Training
Cross-training is a mode of training that can be used to
maintain general conditioning in athletes during periods
of reduced training due to injury or during recovery
from a training cycle (33). Cross-training may reduce
the likelihood of overuse injuries because it distributes
the physical stress of training to muscle groups different
from those used during training (87). Multiple-event
athletes also use cross-training to maximize performance
in swimming, cycling, and running. The benefits derived
from cross-training include adaptations of the respiratory,
cardiovascular, and musculoskeletal systems (53,
57, 87). It seems reasonable to expect that cross-training
would maintain some level of conditioning in single-
event athletes who perform another mode of training
(e.g., runners who perform cycling or swimming). To be
effective in maintaining V
.
O2max, cross-training must be
equal in intensity and duration to the athlete’s primary
mode of exercise (37, 56, 85); however, cross-training
will not improve single-event performance to the same
magnitude as mode-specific training only (33).
Detraining
Detraining occurs when the athlete reduces the training
duration or intensity or stops training altogether due to
a break in the training program, injury, or illness. In the
absence of an appropriate training stimulus, the athlete
experiences a loss of the physiological adaptations
brought about by training. It has been demonstrated
that most of the physiological adaptations attained with
training regress rapidly toward pretraining levels when
the training stimulus is removed (27, 29, 52). To avoid
some of the effects of detraining, the use of other training
modes may be beneficial; however, cross-training
may only attenuate some of the loss of physiological
adaptation normally seen during complete cessation of
training. Aerobic endurance athletes can minimize the
effects of detraining by continuing to use their primary
mode of exercise at reduced frequency and intensity, if
possible (82).
Tapering
Tapering is an important component of the training
program as aerobic endurance athletes prepare for
major competition. Tapering involves the systematic
reduction of training duration and intensity, combined
with an increased emphasis on technique work and
nutritional intervention. The objective of tapering the
training regimen is to attain peak performance at the
time of competition. While the duration of the taper is
dependent on numerous factors, a typical tapering period
may last between 7 and 28 days (63). Although most of
the available research on tapering has been conducted on
swimmers (17, 46, 79), the use of tapering is not limited
to these aerobic endurance athletes. Research among
runners and cyclists has shown that these endurance athletes
also benefit from a well-planned tapering regimen
(63, 64, 75). Tapering before competition helps facilitate
recovery and rehydration and promotes increases in
muscle and liver glycogen stores (63).
There are several types of tapering models that may be
employed by athletes in order to restore impaired physiological
capacities resulting from the rigors of training.
The most common tapering models are linear, step, and
progressive tapers (79). The linear taper is characterized
by a gradual decrease in the overall daily training volume
throughout the duration of the taper. In contrast, a step
taper is typified by an abrupt and considerable reduction
(normally =50%) in training volume that is maintained
throughout the duration of the taper without fluctuation.
The progressive taper uses a combination of the linear
and step tapering models. This model is associated with
a rapid 10% to 15% immediate reduction in training
volume, with smaller, more gradual reductions in volume
at each tier. Training volume is systematically reduced
while intensity and frequency are maintained.
Resistance Training
Resistance training is an important but often overlooked
factor in improving performance in aerobic endurance
athletes. Overall, research on the effects of resistance
training on performance in trained aerobic endurance
athletes is limited; however, some data suggest that
benefits can be derived from performing resistance
training during aerobic endurance training. Of particular
importance, Hickson and colleagues (45) demonstrated
that although the V
.
O2max of highly trained aerobic athletes
did not improve as a result of resistance training,
there was an improvement in short-term exercise performance
during both cycling and running. Benefits that
aerobic endurance athletes may obtain from performing
resistance training include faster recovery from injuries,
prevention of overuse injuries, and reduction of muscle
imbalances. Increased strength is important for various
aspects of aerobic endurance competition, including hill
climbing, bridging gaps between competitors during
breakaways from groups, and the final sprint (87). More
recently Mikkola and colleagues (62) examined the
influence of a variety of resistance training programs
on the running performance of recreational runners.
Muscle endurance training and explosive resistance and
heavy resistance training programs all improved running
performance on a treadmill.
Chapter 17 provides guidelines for designing resistance
training programs that can apply to aerobic endurance
athletes; refer to scenario C for a sample program
that focuses on a high school cross-country runner.
Altitude
Altitude can be defined as the height above sea level.
Altitude is classified into several categories, ranging
from sea level (>500 m) to low (>500–2,000 m), moderate
(>2,000–3,000 m), high (>3,000–5,500 m), and
extreme (>5,500 m) (30). Contrary to popular belief, the
percentage of oxygen is the same at different altitudes
(66). However, as altitude increases, the atmospheric
pressure drops, causing a reduction in partial pressure
(PO2), which acts as the driving force for gas exchange
in the lungs (30, 66). This leads to a cascade of physiological
responses to compensate for the reduction
in PO2. Subsequently, aerobic endurance performance
decrements upon acute altitude exposure may begin to
occur at altitudes as low as 700 m (86).
Acclimatization to altitude may occur between 12 and
14 days at moderate altitudes up to 2,300 m; however, it
has been found that this process may take up to several
months (86). According to Wyatt (86), recommendations
for optimizing performance at altitude vary dramatically,
from arriving immediately before competition (24–48
hours) to 12 weeks of altitude exposure.
Many elite and subelite athletes train at altitude to
produce an ergogenic effect. In order to experience a
benefit from this type of training, it has been reported
that an athlete must receive a hypoxic dose of training
=12 hours/day for a minimum of three weeks at moderate
altitude (approximately 2,100–2,500 m) (51, 86).
“Live high, train low” (LHTL) is a method commonly
used by athletes seeking to benefit from altitude training.
The LHTL requires individuals to live at moderate
altitudes, between 2,000 and 3,000 m, and train at near
sea level (51). This method of training allows athletes
to simultaneously experience the benefits of altitude
acclimatization and training at sea level (84). Thus,
LHTL may potentially provide an ergogenic benefit by
allowing athletes to take advantage of the metabolic and
hematological adaptations experienced when living at
altitude to augment neuromuscular development at lower
altitudes (30, 84).
Conclusion
Training to improve aerobic endurance performance
requires a well-developed and scientifically based
program. The training program should be developed
in conjunction with periodic performance assessment
and should be structured to enhance the strengths and
improve the weaknesses of the athlete. A combination of
a variety of the training types described in this chapter
should be used so that all physiological systems involved
in successful performance are overloaded and challenged
to respond with positive adaptations.
Training programs should be developed far enough in
advance and with enough structure to ensure enhancement
of performance, but with enough flexibility to
avoid overuse injuries and overtraining. Although other
forms of training can be employed to avoid boredom
and overtraining, activity-specific training results in
the best adaptations to training and ultimately the most
improvement in performance.