Transcript Adaptations to Exercise Training

Adaptations to Exercise
Training
Introduction
Exercise training can be defined as
participation in chronic, organized physical
activity, with the goal of improving athletic
performance or specific health and fitness
parameters
Principles of Exercise adaptation
Specificity of Training
– A specific exercise elicits a specific training
response
Overload Principle
– Improvement in performance capacity occur when
regular physical activity is increased above the
level that the performer usually experiences
– Three factors
Frequency
Intensity
duration
The Principle of Individual Differences
– No two individuals are the same
– Unique motor performance profile, and training
strategies may need to be customized to match the
individual’s rate of improvement
Types of Anaerobic Exercise Training
Increases in muscular strength generally
require exercise intensities of least 30% of
maximal voluntary contractile strength (MVC)
Isometric Exercise
No change in joint position
Desirable in some rehab. situation
Little or no equipment
Can be done almost anywhere
35 °
45 °
Better to perform at various joint angles Joint angle
% strength gain
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55°
Dynamic Resistance Exercise
– Changes in muscle length and joint angles
– Concentric muscle contractions can offer very
forces and thus an appropriate overload stimulus
– Eccentric muscle produce more muscular force
than that obtained during an isometric muscle
contraction
– Eccentric or lengthening muscle contractions is
both highly fatiguing and highly susceptible to
muscle soreness
Assessing Success of Anaerobic
Exercise Training
Dynamic muscle strength can be estimated
using the 1 RM (repetition maximum)
Anaerobic power maximum amount of force
that can be generated over a period of time
– Margaria power test or Wingate cycling terst
Exercise Tests
Aerobic Exercise Training
– Low intensity or relatively low force levels
– Continuous training
One type of aerobic exercise training
– Exercise at a low intensity for a duration sufficient for
creating an aerobic overload
– Workload may be estimated as a percentage of maximum heart
rate or a percentage of VO2max
– Aerobic exercise should be performed at an intensity of about
60 to 80% of maximal heart rate
Rating of Perceived Exertion
– Borg (1970s) discovered that our sense of effort
bears a close relationship to actual workload
– Borg’s scale correlates well with heart rate and
VO2 max
Rating of Perceived Exertion
Interval Training
– Alternating higher-intensity
exercise bouts with rest
periods, overload stimuli
can be applied that stress
the intermediate energy
systems and long-term
aerobic systems
– Major advantage is that
more total work can be
done by dividing it into
several bouts than by
performing it continuously
Other Types of Exercise Training
Fartlek training
– Designed by Swedish exercise
– A type of alternating fast-slow training
Hollow sprints
– Alternate periods of sprint, jogging, and walking
Long-Term Adaptations to Anaerobic
Exercise Training
Muscle Strength
– Muscle strength to
increase with long-term
resistance exercise
training
– Initial strength increase
can be dramatic
– Most of gain occurs
during the first month,
subsequent gains much
more slow,
– Strength decrease as
detraining persists
– Major part of initial gain
in strength originates in
the nervous system
– Learn how to activate
more motor units in the
muscles responsible for
action or how to activate
them more efficiently
– Nervous system learns
task in a more
coordinated fashion
Training the Brain
– Thinking about performing a maximal voluntary
muscle contraction on a regular basis can improve
muscular strength
Muscle Fiber Adaptations
Slow twitch muscle fibers
are recruited or brought
into action first, with the
fast twitch muscle fibers
recruited as the force
increases
Fast-twitch fibers to
hypertrophy even more
than slow-twitch fibers
Long-Term Adaptations to Aerobic
Exercise Training
An expect of VO2max to increase as the aerobic
training program progress
Increase the efficiently of the oxygen
utilization system
Respiratory Adaptations
– Lung become more capable at extracting from the
inhaled air and exchanging it for CO2
Oxygen-Carrying Adaptations
– Increase myoglobin in muscle with endurance
exercise, facilitating the delivery of O2 to
mitochondria
Blood-Delivery Adaptations
– Endurance training increases the size of the heart
– Total blood volume increases helps O2 delivery
and regulation of body temperature
– An increase in the number of RBC helps to
provide more oxygen-carrying hemoglobin
– Stroke volume increases with training
Energy Production Adaptations
– More mitochondria in the trained individuals
– Enzymes for aerobic metabolism increase in
concentration and efficiency
– Muscle learns to contain more glycogen
– Beta-oxidation increases to better use fat stores for
energy
Other Aerobic Adaptations
– Increase in the proportion of slow-fibers
– Increase fatigability of most muscle fibers
– Better handle the heat produced
Summary of Anaerobic and Aerobic
Training Adaptations
The specificity and overload principles are key
to understanding and predicting adaptations
that occurs with training
Floor-and-ceiling effect of hemoglobin
Antagonism between Anaerobic and Aerobic
Training
– Training aerobically may hinder anaerobic
performance and vice versa
Strength training decrease muscle myoglobin content
Resistance exercise training increase the proportion of
fast-twitch muscle fibers
Detraining
Once training stops, the positive effects of
resistance exercise or endurance training wear
off at about the same rate that training
occurred
The Space Environment
30 days of space flight,
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muscle may atropy as much as 20%,
muscle strength decrease by about 20%
Bone mass decrease about 1 to 2 % per month
Problems in balance and postural control
VO2max can decrease by as much as 25% after
20 day of bed rest
Percent change in
gastrocnemius and
soleus muscle volume
from preflight to
postflight recovery days
4 (R+4) and 19 (R+19).
*P < 0.05 vs. preflight.
†P < 0.05 vs.
gastrocnemius.
Scott Trappe et al., 2009
Overtraining
Overtraining is a physical, behavioral, and
emotional condition that occurs when the
volume and intensity of an individual's
exercise exceeds their recovery capacity.
They cease making progress, and can even
begin to lose strength and fitness.
Overtraining is a common problem in weight
training, but it can also be experienced by
runners and other athletes.
Overtraining
General adaptation syndrome
– Hans Selye (1950s), stressed and allowed to
recover, rats grew stronger, if repeatedly stressed
without sufficient time for recovery, rats grew
weaker
Cure for overtraining
– Reduce the intensity, duration, frequency of
exercise
– Training levels should be increased slowly and
regular rest period
– Maintain adequate diet and plenty of sleep
Tapering
Refers to the practice of reducing exercise in the days
just before an important competition.
Tapering is customary in many endurance sports,
such as the marathon, athletics and swimming.
For many athletes, a significant period of tapering is
essential for optimal performance. The tapering
period frequently lasts as much as a week or more
Tapering
Swimmers decrease their training for 15 days
resulted in a 25% increase in muscular power
and 4% performance improvement
Reducing training volume several weeks
before big meet to enhance performance
Tapering may be one way of compensating for
overtraining during part of the training period
Discussion
What biochemical changes may occur each
bout during interval training (glucose, lactate
etc.) and why.
Can you using the University’s campus,
(gymnasiums, stadiums, buildings etc.) to plan
a Fartlek training (drawing a running course)
for distance runner.
How do you do to detect subjective and
objective overtraining to athletes.