One of the greatest benefits of water training is being able to train
all of the components of fitness in one low impact and enjoyable
program. The water environment allows a client to strengthen muscles in a
functional, upright position, especially in the trunk area. Performing
basic oppositional motor patterns (i.e., walking and running) utilizing
the water's resistance enhances functional fitness as the body
stabilizes itself against resistance of the water’s weight. Thus, the
true power of water exercise lies in its ability to provide specific
resistance in an upright and functional body position.
Fitness
Components such as posture, CV, stretching, strengthening, core
stability, balance, agility, proprioception and ADL's, are some of the
more popular components that may be easily learned and trained in a well
balanced aquatic fitness program. 
The
principle of Specificity (of training) literally means training that is
directly specific to the task or need - i.e. - the basic fitness
requirement for any individual.
For example the problem, your client has poor balance and has fallen several times.
Then the #1 fitness requirement is that the client needs to specifically train for balance.
Solution:
The feet are the base of support in shallow water and, since water has a
3 dimensional effect around the body for support, someone with poor
balance can practice balance exercises in the water safely. To do this
you can use simple walking patterns to begin balance training. First
start the client walking to create an inertia effect (water current)
then stop with both feet in contact with the pool floor. Add sculling to
support balance and posture and work on standing tall in the water.
Exercise
Check: Did the current affected balance or was it easy to stand still?
If the current affected balance then this is the starting point and
this exercise can be repeated until the client feels confident. Once
balance has been established with both feet on the pool floor the
exercise can be progressed to stopping to scull and lifting one foot off
the pool floor. As balance improves a further progression can be
taking the hands out of the water and so on until balance has been
regained and maintained.
If this individual had been trained
using speed, rebounding or any higher level cardiovascular movement the
training would have been totally ineffective for the specific need i.e.
balance. Adding speed would not have simulated the correct training
effect.
Training in water will benefit land movement
but only if techniques for training a specific component of fitness is
utilized. What must be noted is that water exercise techniques are
unique as compared to land training because of the protection and
properties of water. Research supports this concept.
Using the principles of specificity of training with good technique can make for a very efficient and well balanced workout .
For
example, the main focus of cardiovascular fitness is to benefit the
heart and circulatory system to prevent heart disease. Progressive
overload as well as interval training of “go intense then less intense”
will train a person to perform more total work while lowering resting
heart rate. 
Developing cardiorespiratory endurance sets or segments in water must
be performed by engaging large muscle groups of the lower body
muscles, dynamically or rhythmically, continuously or intermittently, at
low through moderate to high intensity exercise. The exercise design
needs to be more than three or more minutes in duration to utilize
aerobic or with oxygen energy systems. Simply stated cardiovascular or
cardio-respiratory training is training working on the breathing and
volume of oxyegen uptake so that the heart is more efficient.
Muscular endurance is
the ability of a muscle, or group of muscles, to repeatedly exert force
against a given sub-maximal resistance or to sustain an isometric
contraction over time. Generally measured by how many times the muscle
or group of muscles can contract before reaching momentary fatigue.
Programs designed to increase muscular endurance utilize lower
resistance and higher numbers of repetitions.
Often
In the water, most instructors do not do enough variety, sets or reps
for effective muscular conditioning and therefore their clients may not
reach attainable training levels. To do this effectively:
Be sure to utilize the correct joint action to properly engage the muscle
Body position must Power down into the resistance of the water rather than just lift up with buoyancy
Perform at least 8 – 25 repetitions to properly train and fatigue the muscle
Provide 1 to 2 sets for strength (with equipment) OR 3-5 sets for endurance(without equipment)
Need to feel that the muscle is fatigued for efficacy or to hypertrophy
Add power not just speed and don’t use momentum.
Work with a muscle is created when the movement is started & stopped in good form.
Muscles do support good posture. Good form is working in proper body alignment & posture with good technique.
Add active recovery or filler moves in between sets or super set (no break in between sets) for more advanced groups.
Promoting
participants to exercise muscular endurance “in their target range”
will help them achieve the most benefits at a reduced risk for injury.
Flexibility is the optimal range of motion around the joints and their corresponding muscle
groups without sacrificing stability or inducing pain and discomfort.
The key to improving and maintaining flexibility is frequency and
consistency of use. Stretch between muscle strengthening sets. 
Recommendations for Flexibility:
Stretch muscles between sets when targeting specific muscle groups.
Work
through a comfortable active range of motion throughout the work-out to
maintain good flexibility. A flexible muscle is a safe muscle since it
can be strengthened throughout its length. ROM can be incorporated
through the program for all exercises. Don’t use land stretches, use
the water for assistance and massage effect.
Incorporate mostly
active stretching techniques. You need dynamic stretching for all ADL’s,
(Active daily living). If you do all stationary stretching you are only
training for stationary flexibility.
To sum up:
The instructor's job is to help people gain results. Exercise goals
must be specifically targeted or mimicked to gain the same or more
results as land exercise. Therefore, the instructor is instrumental in
teaching and cueing their clients to understand how to train each
component for maximal results.
Moving through the water can be
compared to lifting weights. The law of action-reaction applies 100% of
the time in water. The more force used, the higher the resistance force
applied. Water's "weight" facilitates specific ways to promote work.
This type of "active" muscular endurance conditioning cannot be
accomplished in a similar functional manner on variable, stationary land
resistance machines. When a muscle is strengthen the opposing partner
muscles is actively stretched. That is why full range or maintaining
proper range of motion (versus just speed ) is important to efficacy.
Here
are some of the more popular components of fitness that will need to
be addressed with a well balanced aquatic fitness program
CV endurance for both aerobic & anaerobic fitness,
stretching, active and dynamic stretching,
muscular strengthening & endurance
core stability,
static and dynamic balance,
agility,
coordination,
Proprioception, ADLS, and posture....
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