general fitness

1. GENERAL FITNESS
Fitness
Fitness is a general term used to describe the ability to perform physical
work. Performing physical work requires cardiorespiratory functioning, muscular
strength and endurance, and musculoskeletal flexibility.
To become physically fit, individuals must participate regularly in some
form of physical activity that uses large muscle groups and challenges the
cardiorespiratory system. Individuals of all ages can improve their general fitness
status by participating in activities that include walking, biking, running,
swimming, stair climbing, cross-country skiing, and/or training with weights.
Fitness levels can be described on a continuum from poor to superior based on
energy expenditure during a bout of physical work.
These ratings are often based on direct or indirect measurement of the body’s
maximum oxygen consumption (VO2 max). Oxygen consumption is influenced by
age, gender, heredity, inactivity, and disease.
Endurance
Endurance (a measure of fitness) is the ability to work for prolonged periods of
time and the ability to resist fatigue.
It includes muscular endurance and cardio-vascular endurance.
Muscular endurance refers to the ability of an isolated muscle group to perform
repeated contractions over a period of time, whereas cardiovascular endurance
refers to the ability to perform large muscle dynamic exercise, such as walking,
swimming, running for long periods of time.

2. Aerobic Exercise Training (Conditioning)
Aerobic exercise training, or conditioning, is augmentation of the energy
utilization of the muscle by means of an exercise program.
The improvement of the muscle’s ability to use energy is a direct result of
increased levels of oxidative enzymes in the muscles, increased mitochondrial
density and size, and an increased muscle fiber capillary supply. Training is
dependent on exercise of sufficient intensity, duration, and frequency.
Training produces cardiovascular and/or muscular adaptation and is reflected in an
individual’s endurance. Training for a particular sport or event is dependent on the
specificity principle; that is, the individual improves in the exercise task used for
training and may not improve in other tasks. For example, swimming may enhance
one’s performance in swimming events but may not improve one’s performance in
treadmill running
Adaptation
The cardiovascular system and the muscles used adapt to the training stimulus over
time. Significant changes can be measured in as little as 10 to 12 weeks.
Adaptation results in increased efficiency of the cardiovascular system and the
active muscles. Adaptation represents a variety of neurological, physical and
biochemical changes in the cardiovascular and muscular systems.
Adaptation is dependent on the ability of the organism to change and the training
stimulus threshold (the stimulus that elicits a training response).
The person with a low level of fitness has more potential to improve than the one
who has a high level of fitness.
Training stimulus thresholds are variable. The higher the initial level of fitness, the
greater the intensity of exercise needed to elicit a significant change.

3. DETERMINANTS OF AN EXERCISE PROGRAM
Effective endurance training for any population must produce a conditioning or
cardiovascular response. Elicitation of the cardiovascular response is dependent on
three critical elements of exercise: intensity, duration, and frequency.
 Intensity
Determination of the appropriate intensity of exercise to use is based on the
overload principle and the specificity principle.
Overload Principle
Overload is stress on an organism that is greater than that regularly encountered
during everyday life. To improve cardiovascular and muscular endurance, an
overload must be applied to these systems. The exercise load (overload) must be
above the training stimulus threshold (the stimulus that elicits a training or
conditioning response)for adaptation to occur.
Once adaptation to a given load has taken place, the training intensity (exercise
load) must be increased for the individual to achieve further improvement.
Training stimulus thresholds are variable, depending on the individual’s level of
health, level of activity, age, and gender. The higher the initial level of fitness, the
greater the intensity of exercise needed to elicit a change.
Determining the maximum heart rate and the exercise heart rate for training
programs provides the basis for the initial intensity of the exercise.
When the individual is young and healthy, the maximum heart rate can be
determined directly from a maximum performance multistage test, extrapolated
from a heart rate achieved on a predetermined submaximum test or, less
accurately, calculated as 220 minus age.
 HR achieved in predetermined
submaximum stage.
 220-age (less accurate)
 Determine exercise heart rate
Karvonen’s formula (heart rate reserve)
Exercise heart rate = HR rest + 60-70% (HR max – HR rest)

4.  The exercise heart rate is determined in one of two ways:
(1) As a percentage of the maximum heart rate (the percentage used is dependent
on the level of fitness of the individual);
(2) Using the heart rate reserve (Karvonen’s formula).
Karvonen’s formula is based on the heart rate reserve (HRR), which is the
difference between the resting heart rate (HR rest) and the maximum heart rate
(HR max). The exercise heart rate is determined as a percentage (usually 60% to
70%) of the heart rate reserve plus the resting heart rate (see box above).When
using Karvonen’s formula, the exercise heart rate is higher than when using the
SpecificityPrinciple
The specificity principle as related to the specificity of training refers to
adaptations in metabolic and physiological systems depending on the demand
imposed.
There is no overlap when training for strength–power activities and training for
endurance activities.
Even when evaluating aerobic or endurance activities, there appears to be little
overlap. When training for swimming events, the individual may not demonstrate
an improvement in VO2 max when running.
 Duration (Time)
The optimal duration of exercise for cardiovascular conditioning is dependent on
the total work performed, exercise intensity and frequency, and fitness level.
Generally speaking, the greater the intensity of the exercise, the shorter the
duration needed for adaptation; and the lower the intensity of exercise, the longer
the duration needed.
A 20- to 30-minute session is generally optimal at 60% to 70% maximum heart
rate. When the intensity is below the heart rate threshold, a 45-minute continuous
exercise period may provide the appropriate overload. With high-intensity
exercise, 10- to 15-minute exercise periods are adequate; three 5-minute daily
periods are effective in some deconditioned patients.

5.  Frequency
Frequency may be a less important factor than intensity or duration in exercise
training. Frequency varies, dependent on the health and age of the individual.
Optimal frequency of training is generally three to four times a week.
If training is at low intensity, greater frequency may be beneficial. A frequency of
two times a week does not generally evoke cardiovascular changes, although
older individuals and convalescing patients may benefit from a program of that
frequency.
 Mode (Type)
Many types of activity provide the stimulus for improving cardiorespiratory
fitness. The important factor is that the exercise involves large muscle groups that
are activated in a rhythmic, aerobic nature.
However, the magnitude of the changes may be determined by the mode used.
For specific aerobic activities such as cycling and running, the overload must use
the muscles required by the activity and stress the cardiorespiratory system
(specificity principle). E.g. cycle, treadmill etc.
If endurance of the upper extremities is needed to perform activities on the job, the
upper extremity muscles must be targeted in the exercise program. E.g. cycle
ergometer.
ReversibilityPrinciple
The beneficial effects of exercise training are transient and reversible. Detraining
occurs rapidly when a person stops exercising. After only 2 weeks of detraining,
significant reductions in work capacity can be measured, and improvements can be
lost within several months. A similar phenomenon occurs with individuals who are
confined to bed with illness or disability: the individual becomes severely
deconditioned, with loss of the ability to carry out normal daily activities as a result
of in activity. The frequency or duration of physical activity required to maintain a
certain level of aerobic fitness is less than that required to improve it.

6. EXERCISE PROGRAM
A carefully planned exercise program can result in higher levels of fitness for the
healthy individual, slow the decrease in functional capacity of the elderly, and
recondition those who have been ill or have chronic disease. There are three
components of the exercise program:
 Warm-up period,
 Aerobic exercise period, and
 Cool-downperiod.
Warm-Up Period
Physiologically, a time lag exists between the onset of activity and the bodily
adjustments needed to meet the physical requirements of the body. The purpose of
the warm-up period is to enhance the numerous adjustments that must take place
before physical activity.
PhysiologicalResponses
During this period there is:
 An increase in muscle temperature. The higher temperature increases the
efficiency of muscular contraction by reducing muscle viscosity and
increasing the rate of nerve conduction.
 An increased need for oxygen to meet the energy demands for the muscle.
 Extraction from hemoglobin is greater at higher muscle temperatures,
facilitating the oxidative processes at work.
 Dilatation of the previously constricted capillaries with increases in the
circulation, augmenting oxygen delivery to the active muscles and
minimizing the oxygen deficit and the formation of lactic acid.
 Adaptation in sensitivity of the neural respiratory center to various exercise
stimulants.
 An increase in venous return. This occurs as blood flow is shifted centrally
from the periphery.

7. Purposes
The warm-up also prevents or decreases:
 The susceptibility of the musculoskeletal system to injury.
 The occurrence of ischemic electrocardiographic (ECG) changes and
arrhythmias.
Guidelines
The warm-up should be gradual and sufficient to increase muscle and core
temperature without causing fatigue or reducing energy stores. Characteristics of
the period include:
 A 10-minute period of total body movement exercises, such as calisthenics,
and walking slowly.
 Attaining a heart rate that is within 20 beats/min of the target heart rate.
Aerobic Exercise Period
The aerobic exercise period is the conditioning part of the exercise program.
Attention to the determinants of intensity, frequency, duration, and mode of the
program, as previously discussed, has an impact on the effectiveness of
the program.
The main consideration when choosing a specific method of training is that the
intensity should be great enough to stimulate an increase in stroke volume and
cardiac output and to enhance local circulation and aerobic metabolism in the
appropriate muscle groups.
The exercise period must be within the person’s tolerance, above the threshold
level for adaptation to occur, and below the level of exercise that evokes clinical
symptoms. In aerobic exercise, submaximum, rhythmic, repetitive, dynamic
exercise of large muscle groups is emphasized.
There are four methods of training that challenge the aerobic system: continuous,
interval (work relief), circuit, and circuit interval.

8. ContinuousTraining
 A submaximum energy requirement, sustained throughout the training
period, is imposed. Once the steady state is achieved, the muscle obtains
energy by means of aerobic metabolism.
 Stress is placed primarily on the slow-twitch fibers
 The activity can be prolonged for 20 to 60 minutes with-out exhausting the
oxygen transport system.
 The work rate is increased progressively as training improvements are
achieved.
 Overload can be accomplished by increasing the exercise duration.
 In the healthy individual, continuous training is the most effective way to
improve endurance.
Interval Training
With this type of training, the work or exercise is followed by a properly
prescribed relief or rest interval.
Interval training is perceived to be less demanding than continuous training.
In the healthy individual, interval training tends to improve strength and power
more than endurance.
 The relief interval is either a rest relief (passive recovery) or a work relief
(active recovery); and its duration ranges from a few seconds to several
minutes.
 The longer the work interval, the more the aerobic system is stressed.
 With a short work interval, the duration of the rest interval is critical if the
aerobic system is to be stressed (a work/recovery ratio of 1:1 to 1:5 is
appropriate).
 A rest interval equal to one and a half times the work interval allows the
succeeding exercise interval to begin before recovery is complete and
stresses the aerobic system.

9. Circuit Training
 Circuit training employs a series of exercise activities. At the end of the last
activity, the individual starts from the beginning and again moves through
the series.
 The series of activities is repeated several times.
 Several exercise modes can be used involving large and small muscle groups
and a mix of static or dynamic effort.
 Use of circuit training can improve strength and endurance by stressing both
the aerobic and anaerobic systems.
Circuit-Interval Training
 Combining circuit and interval training is effective because of the interaction
of aerobic and anaerobic productionof ATP.
 In addition to the aerobic and anaerobic systems being stressed by the
various activities, with the relief interval there is a delay in the need for
glycolysis and the production of lactic acid prior to the availability of
oxygen supplying the ATP.
Cool-Down Period
A cool-down period is necessary following the exercise period.
Purpose
The purposeof the cool-down period is to:
 Prevent pooling of the blood in the extremities by continuing to use the
muscles to maintain venous return.
 Prevent fainting by increasing the return of blood to the heart and brain as
cardiac output and venous return decreases.
 Enhance the recovery period with the oxidation of metabolic waste and
replacement of the energy stores.
 Prevent myocardial ischemia, arrhythmias, or other cardiovascular
complications.

10. Guidelines
Characteristics of the cool-down period are similar to those of the warm-up period.
Total-body exercises such as calisthenics and static stretching are appropriate.
The period should last 5 to 10 minutes.