Aerobic Training - Swimming



In order to combine aerobic with resistance exercise it's a good idea to choose a leisure centre (GLL/Better in London are NOT recommended) which has a good pool.

Choosing a Good Swimming Pool

The Eltham Centre - South London
Not Recomended
A swimming pool can be a dangerous place.
When choosing a good swimming pool various factors should be considered,
Is the pool and the surrounding areas, showers, toilets and changing areas clean ?
Is the pool-side free of obstructions ?
Is the pool well designed and well lit ?
Are the non-swimming areas properly supervised ?


Eltham Swimming Pool
Not Recommended
Eltham Swimming Pool, (see right).
It is situated in the Eltham Centre (see right above) which also houses a Library, council offices etc.
It is an attractive building externally, but the pool and gym are very poorly designed to an obviously limited budget.
The pool, a typical example of a GLL Better Pool, is shown on the right above - note the blue rope thrown carelessly on the floor where children and older people may not see it, and trip.
The Eltham staff also have a nasty habit of leaving the large steel bolts, that secure the lane dividers to the pool wall, on the pool-side.
Standing on one of these steel bolts could lead to a fatal fall, particularly for an older person.
They also leave the same bolts attached under water to the pool-wall, where they could inflict horrendous injuries.

A good pool will ensure that all areas open to the public, other than the actual poolside, will be covered in rubber matting so that people using the pool will not accidentally slip over. - GLL Better do not do this.


Many GLL Better Pools are definitely not clean - (in fact the changing areas usually stink !) , with poorly designed flooring which lacks proper drainage and therefore collects pools of standing, stagnant water..
If you wouldn't accept the standard of cleanliness you see at the pool, changing areas, toilets and showers in your own bathroom - the do not use the pool.

Are the non-swimming areas (changing areas, toilets and showers) properly supervised - or is it possible for undesirable elements to loiter and harass bona-fide swimmers - particularly older people (see right).
Toilets must be clean, wash basins should have reliable hot water, showers should be powerful and hot.

There should be no areas of standing water in the non-swimming areas.

GLL Better pools in London, such as Woolwich, Greenwich and particularly Eltham do not meet these minimum standards. - (showers that just dribble barely warm water, sink taps that do not work, or if they work, run cold, empty soap dispensers, broken hairdriers etc,etc).

In addition there have been incidences of dangerously high bacterial levels, and dangerously high chlorine (?) levels, which resulted in temporary pool closure !
And if you are wondering why there is a problem at Eltham then you are advised to consider the photo (right) of the Centre Manager - Ms.(name removed on the advice of the Metropolitan Police) - and this is not a photo taken when Ms. (name removed on the advice of the Metropolitan Police)  was young and foolish, many years ago, before she took on the responsibility of a large facility - this is a recent photo of a young graduate manage who is obviously not sufficiently experienced to provide a satisfactory service for those using the centre.
And one wonders what the Royal Borough of Greenwich might say about this catalogue of disasters, particularly their health and safety department ?

The manageress of the Eltham Centre, while publicly publishing her image on Facebook, does not want to be seen as the manageress of the Eltham centre - which, considering her record in this position, is not surprising.
The centre manager's name is freely available on the web, however.
If you want to know the name of the Eltham Centre manageress go to:


click below for more information about


Having found a good swimming pool, one should consider one's current state of health.
Anyone with a history of cardio-vascular disease should be very careful about swimming.
If you haven't swum for some time, take it very easy to begin with.
Any style is satisfactory, although the Butterfly (Fly) or Dolphin Crawl are not recommended except for the experienced.
Speed is not essential. The object of the exercise is to raise the rate of respiration, and the heart rate, for an extended period - but begin very slowly for short periods, taking regular rests.
When you can swim for 30 minutes without too much trouble consider using 'swimming gloves' (available from

Aquatic Gloves
Swimmers wear gloves during training to increase water resistance, with the webbed fingers spreading wide to create more drag.
The added resistance provides more work for the upper body, giving the shoulders, arms, chest and back an intense workout and toning muscles well beyond normal swimming.
Even the legs are forced to kick harder to propel the body, toning the thighs, hamstrings and calves.
Wrist Weights for Swimming
Training with swim gloves builds strength and, in turn, improves a person's swimming stroke, creating smoother movement and enhanced technique for better in-pool performance.

Aside from strengthening muscles, swimming gloves force the entire body to work harder to fight through the added water resistance, intensifying an already effective aerobic workout.
Sustained training with swim gloves will result in increased endurance, since the body's cardiovascular system adapts to the stress placed on it due to the fierce resistance.
Once it is possible to swim comfortably with swimming gloves, the next step is to use wrist weights (available from

These can, at a later date, be combined with swimming gloves to increase the workload while swimming.
One of the main advantages of using these aids is that they can dramatically reduce the time spent in the pool - after all you have better things to do that swim up and down your local leisure centre pool for hours on end.
This high intensity aerobic pool work out will do wonders for your cardio-vascular efficiency, and will ensure good 'definition' and excellent shape for the muscles that you will be building in the gym.

What to Wear in the Pool

What you wear when you exercise is extremely important.
It is part of your mental preparation for your workout.
You can feel good by looking good and feeling good will undoubtedly improve your overall performance while you train.

What to wear in the pool - for the ladies - DO NOT wear a bikini.
Bikinis are for sunbathing - not exercising.
Real athletes (and you will be a real athlete) wear professional gear.
For ladies the premier label is, of course, Speedo, who produce well designed professional swimsuits
For that really professional look there is a 'body skin' which is a cover-all ladies swimsuit which manages to be devastatingly attractive, while also being practical and extremely efficient in the pool.
This style of ladies swimwear is also highly suitable for ladies who have to consider religious sensibilities when undertaking pool-based exercise.

Mens Jammers
What to wear in the pool for guys - DO NOT Wear floppy so-called 'board shorts' (you are not surfing), which are probably more suitable for gardening 
'Jammers' are acceptable (A jammer is a style of swimsuit used mainly in competition to obtain speed advantages.
Men's Thong
to be Worn Under Jammers
They are made of nylon and lycra/spandex material and have a form fitting design to reduce water resistance.
They provide moderate coverage from the mid-waist to the area above the knee, somewhat resembling cycling shorts or compression shorts worn by many athletes.

It is wise to wear a swimmer's 'jock-strap' or thong (see right) underneath Jammers.
Thongs or 'jock-straps' are recommended as they make allowance for the centre rear seam which are used in good quality Jammers.
They provide greater leg coverage than swim briefs and square leg suits, although they also have slightly more water resistance.) (available from

Add cap Men's Thong
to be Worn Under Leg-Skins
Leg Skins
More professional swimwear for men and boys are 'leg-skins'.
A Leg-skin is a type of competitive swimwear worn by male swimmers.
Most leg-skins (available from are made of technologically advanced lycra-based fabrics designed to hug the body tightly and provide increased speed and decreased drag resistance in the water.
The leg-skin covers from the swimmer's mid-waist to his ankle and resembles leggings.

The disadvantages of leg-skins is that they are difficult to put on, and are also very, very expensive.

Tom Daley in Speedos
Toot Low Rise
Competition Trunk
Leg-skins also benefit from the wearing of a swimmers 'jock-strap' or thong underneath (see right above)(available from

For the daring (a good physique is essential, so perhaps these can be invested in when your training begins to show results), the most comfortable and efficient swimwear are 'Japan-cut' bikini briefs as produced by Toot (available from, Speedo (see Tom Daley) and Arena (available from
These are lightweight, absorb very little water (and so dry easily), and give good support (no 'jock-strap' or thong is needed as additional support)

A new Range of men's racing and competition swimwear by Seobean, (Speedo style but better designs), has been introduced from China in a range of attractive colors.

(see below)

highly reccomended
best prices from


Yingfa Racing Mirror Goggles
Swim goggles are absolutely essential for long periods in the pool, especially if you swim front crawl.
DO NOT use Speedo as they are expensive considering they often leak and 'mist up'.
The best, and most comfortable swim goggles are made by the Chinese company Yingfa.
Their best, and most expensive goggles have mirror lens coatings which make them look very stylish (available from

Speedo Aquabeat MP3 Player

Principles of Swimming

The basic principle of swimming is buoyancy.
The human body has a high water content and its density is close to the density of water.
Due to its cavities (most prominently the lungs), the average density of the human body is lower than that of water, so it naturally floats.
There are two ways to swim faster:
increase power
reduce water resistance
Because the power needed to overcome resistance increases with the third power of the velocity, the first option is not really effective.
To increase velocity by 10%, one would need to increase the power by more than 30%.

Balance: how to have a horizontal water position

Due to the lungs, the center of buoyancy and the center of gravity of the human body are not the same. Therefore the lower body has a tendency to sink. If the body is not horizontal but even slightly inclined, the area it offers to drag is much higher, leading to higher resistance. An easy way to stay horizontal is to lean forward and position the head straight in the extension of the spine. In this position the eyes are directed straight downward and the head is more immersed (therefore total immersion).
At the water surface, resistance is proportional to the breadth of a boat. Lying flat on the chest in freestyle or on the back in backstroke exposes the breadth of the body to the water. Rolling on the side reduces the breadth and the resistance. In freestyle and backstroke, one should roll from one side to the other in the stroke and glide on the side as much as possible. When taking breaths, one should take them as little as possible; for beginners it is good to breathe every three strokes and the more trained you are the more strokes in between each breath.

Extended Arm

Sailboats are categorized according to boat length.
This is due to the wave resistance at the surface.
According to Froude, a naval architect in the 19th century, a body moving at the surface of the water creates a wave.
The length of the wave depends on the speed. 
The faster the boat, the longer the wave.
Froude found that resistance goes up dramatically when the wave length reaches the length of the boat.
There is a simple formula connecting wave velocity to wave length (dispersion equation, metric):
Here c is the velocity of the wave in m/s, g is the gravitational acceleration (9.81 m/s2), and l is the wave length in m.
If the maximum swimming speed of c=2.1 m/s is entered, one gets a length of l=2.82 m.
This is about the length of a 2 m swimmer with extended arms.
So the longer you can glide with the extended arm the less wave resistance.

Swim styles

In competitive swimming, four major styles have been established.
The four main strokes in swimming are:

Front Crawl

The Front Crawl

The front crawl is a swimming stroke usually regarded as the fastest of the four front primary strokes.
It is one of two long axis strokes, the other one being the backstroke.
This style is sometimes referred to as the Australian crawl.
For details of the stroke see images below

Arm Movement

The arm movement alternates from side to side. In other words, while one arm is pulling/pushing, the other arm is recovering. The arm strokes also provide most of the forward movement. The move can be separated into three parts: the downsweep, the insweep and the upsweep.
From the initial position, the arm sinks slightly lower and the palm of the hand turns 45 degrees with the thumb side of the palm towards the bottom. This is called catching the water and prepares for the pull. The pull movement follows a semicircle, with the elbow higher than the hand, and the hand pointing towards the body center and downward. The semicircle ends in front of the chest at the beginning of the ribcage.
The push pushes the palm backward through the water underneath the body at the beginning and at the side of the body at the end of the push.
This pull and push is also known as the S-curve.
Sometime after the beginning of the pull, the other arm begins its recovery. The recovery moves the elbow in a semicircle in a vertical plane in the swimming direction. The lower arm and the hand are completely relaxed and hang down from the elbow close to the water surface and close to the swimmer's body. The beginning of the recovery looks similar to pulling the hand out of the back pocket of a pair of pants, with the small finger upwards. Further into the recovery phase, the hand movement has been compared to pulling up a center zip on a wetsuit. The recovering hand moves forward, with the fingers trailing downward, just above the surface of the water. In the middle of the recovery one shoulder is rotated forward into the air while the other is pointing backwards to avoid drag due to the large frontal area which at this specific time is not covered by the arm. To rotate the shoulder, some twist their torso while others also rotate everything down to their feet.
Beginners often make the mistake of not relaxing the arm during the recovery and of moving the hand too high and too far away from the body, in some cases even higher than the elbow. In these cases, drag and incidental muscle effort is increased at the expense of speed. Beginners often forget to use their shoulders to let the hand enter as far forward as possible. Some say the hand should enter the water thumb first, reducing drag through possible turbulence, others say the middle finger is first with the hand precisely bent down, giving thrust right from the start. At the beginning of the pull, the hand acts like a wing and is moved slower than the swimmer while at the end it acts like an oar and is moved faster than the swimmer.
A recreational variation of front crawl involves only one arm moving at any one time, while the other arm rests and is stretched out at the front. This style is called a "catch up" stroke and requires more strength for swimming. This is because the hand is beginning the pull from a stationary position rather than a dynamic one. This style is slower than the regular front crawl and is rarely used competitively: however, it is often used for training purposes by swimmers, as it increases the body's awareness of being streamlined in the water. Total Immersion is a similar technique.

Leg Movement

The leg movement in freestyle is called the flutter kick.
The legs move alternately, with one leg kicking downward while the other leg moves upward. While the legs provide only a small part of the overall speed, they are important to stabilize the body position. This lack of balance is apparent when using a pull buoy to neutralize the leg action.
The leg in the initial position bends very slightly at the knees, and then kicks the lower leg and the foot downwards similar to kicking a football. The legs may be bent inward (or occasionally outward) slightly. After the kick, the straight leg moves back up. A frequent mistake of beginners is to bend the legs too much or to kick too much out of the water.
Ideally, there are 6 kicks per cycle, although it is also possible to use 8, 4, or even 2 kicks.
When one arm is pushed down, the opposite leg needs to do a downward kick also, to fix the body orientation, because this happens shortly after the body rotation.
Alternatively, (but not recomended for aerobic exercise) front crawl can also be swum with a butterfly (dolphin) kick, although this reduces the stability of the swimming position.


Normally, the face is in the water during front crawl with eyes looking at the lower part of the wall in front of the pool, with the waterline between the brow line and the hairline. Breaths are taken through the mouth by turning the head to the side of a recovering arm at the beginning of the recovery, and breathing in the triangle between the upper arm, lower arm, and the waterline. The swimmer's forward movement will cause a bow wave with a trough in the water surface near the ears. After turning the head, a breath can be taken in this trough without the need to move the mouth above the average water surface. A thin film of water running down the head can be blown away just before the intake. The head is rotated back at the end of the recovery and points down and forward again when the recovered hand enters the water. The swimmer breathes out through mouth and nose until the next breath. Breathing out through the nose may help to prevent water from entering the nose. Swimmers with allergies exacerbated by time in the pool should not expect exhaling through the nose to completely prevent intranasal irritation.
Standard swimming calls for one breath every third arm recovery or every 1.5 cycles, alternating the sides for breathing. Some swimmers instead take a breath every cycle, i.e., every second arm recovery, breathing always to the same side. Most competition swimmers will breathe every other stroke, or once a cycle, to a preferred side. However some swimmers can breathe comfortably to both sides. Sprinters will often breathe a predetermined number of times in an entire race. Elite sprinters will breathe once or even no times during a fifty metre race. For a one hundred metre race sprinters will often breathe every four strokes, once every two cycles, or will start with every four strokes and finish with every two strokes.

Body Movement

The body rotates about its long axis with every arm stroke so that the shoulder of the recovering arm is higher than the shoulder of the pushing/pulling arm. This makes the recovery much easier and reduces the need to turn the head to breathe. As one shoulder is out of the water, it reduces drag, and as it falls it aids the arm catching the water; as the other shoulder rises it aids the arm at end of the push to leave the water.
Side-to-side movement is kept to a minimum: one of the main functions of the leg kick is to maintain the line of the body.

The Breast Stroke

The breaststroke is a swimming style in which the swimmer is on his or her chest and the torso does not rotate. It is the most popular recreational style due to its stability and the ability to keep the head out of the water a large portion of the time. In most swimming classes, beginners learn either the breaststroke or the front crawl first. Since the breaststroke can be swum with the eyes almost always above water, it is important in lifesaving, as it allows the rescuer to approach the victim without losing sight of them. However, in competitive swimming, the breaststroke is regarded as one of the most difficult strokes, requiring comparable endurance and leg strength to other strokes. The stroke itself is the slowest of any competitive strokes and thought to be the oldest of all swimming strokes.

Speed and ergonomics

Breaststroke is the slowest of the four official styles in competitive swimming. The fastest breaststrokers can swim about 1.57 metres per second. Although it is the slowest of the four competitive strokes, it is commonly agreed that it is by far the most difficult to do correctly[citation needed]. It is also often the hardest to teach to rising swimmers after butterfly due to the importance of timing and the coordination required to move the legs properly.
In the breaststroke, the swimmer leans on the chest, arms breaking the surface of the water slightly, legs always underwater and the head underwater for the second half of the stroke. The kick is sometimes referred to as a "frog kick" because of the resemblance to the movement of a frog's hind legs; however, when done correctly it is more of a "whip kick" due to the whip-like motion that moves starting at the core down through the legs.
The body is often at a steep angle to the forward movement, which slows down the swimmer more than any other style. Professional breaststrokers use abdominal muscles and hips to add extra power to the kick, although most do not perfect this technique until the collegiate level. This much faster form of breaststroke is referred to as "wave-action" breaststroke and fully incorporates the whip-kick.

Arm Movement

There are three steps to the arm movement: outsweep, insweep, and recovery. The movement starts with the outsweep. From the initial position, the hands sink a little bit down and the palms face inward, and the hands rotate outward and move apart. During the outsweep the arms stay almost straight and parallel to the surface. The outsweep is followed by the insweep, where the hands point down and push the water backwards. The elbows stay in the horizontal plane through the shoulders. The hands push back until approximately the vertical plane through the shoulders. At the end of the insweep the hands come together with facing palms in front of the chest and the elbows are at the side at the body. In the recovery phase the hands are moved forward again into the initial position under water. The entire arm stroke starts slowly, increases speed to the peak arm movement speed in the insweep phase, and slows down again during recovery. The goal is to produce maximum thrust during the insweep phase, and minimum drag during the recovery phase.

Leg Movement

The leg movement, colloquially known as the "frog kick" or "whip kick", consists of two phases: bringing the feet into position for the thrust phase and the insweep phase. From the initial position with the legs stretched out backward, the feet are moved together towards the posterior, while the knees stay together. The knees should not sink too low, as this increases the drag. Then the feet point outward in preparation for the thrust phase. In the thrust phase, the legs are moved elliptically back to the initial position. During this movement, the knees are kept together. The legs move slower while bringing the legs into position for the thrust phase, and move very fast during the thrust phase. Again, the goal is produce maximum thrust during the in sweep phase, and minimum drag during the recovery phase. In the recovery phase the lower leg and the feet are in the wake of the upper leg, and the feet are pointed to the rear. In the thrust phase all three parts create their own wake, and the flat end of the feet acts like a hydrofoil aligned to give maximum forward thrust. The resulting drag coefficient (or more precisely the frontal area) is thus doubled in the thrust phase.
A fit adult creates a wake. Drag due to a wake is Newtonian drag, increasing with the square of the velocity. For example if the relative speed between the water and the leg is twice as high on the thrust phase than on the recovery phase, the thrust is four times as high as the drag. Assuming the legs are recovered with a relative speed between leg and body which amounts to the same as the relative speed between water and body, the legs must be kicked back with five times the mean velocity of the swimmer. This limits the top speed. Both effects together, velocity and frontal area, yield a thrust-to-drag ratio of 8 for the legs.
Breaststroke can also be swum with the dolphin kick in butterfly.
Humans have strong muscles in the legs and would need swim fins (like a frog) to bring all their power into the water and stand with the sole of the feet on the water. Rather the leg grabs almost as much water as the foot and a small amount of water is accelerated to high kinetic energy, but not much impulse is transferred. The toes are bent, the feet point 45° outwards, the sole points backwards, to mimic a hydrofoil. While closing in a V shape to the rear a small “lifting” force can be felt. Unlike in the other kicks, the joints are moved into extrema. Before the kick the knee is maximally bent and the upper leg is rotating along its axis to its extreme outer position and the lower leg is twisted to extreme, at the end of the kick the ankles are maximally turned to the inside so that the soles clap together to achieve a nozzle effect like in a jelly fish. Therefore training involves getting flexible in addition to fitness and precision.


The easiest way to breathe during breaststroke is to let the head follow the spine. When your elbows have reached the line of your eye and have begun to rise, your head starts to lift. If you use your high elbows as a hinge for the inward sweep of your hands and forearms, you'll create the leverage you need to use your abdominal muscles to bring your hips forward. When your hips move forward, your chest, shoulders and upper back will automatically lift up. Breathing is usually done during the beginning of the insweep phase of the arms, and the swimmer breathes in ideally through the mouth. The swimmer breathes out through mouth and nose during the recovery and gliding phase.
Recreational swimmers often keep their head above water at all times when they swim breaststroke, but this is not recommended for aerobic exercise.

Body Movement

The movement starts in the initial position with the body completely straight, body movement is coordinated such that the legs are ready for the thrust phase while the arms are halfway through the insweep, and the head is out of the water for breathing. In this position the body has also the largest angle to the horizontal. The arms are recovered during the thrust phase of the legs. After the stroke the body is kept in the initial position for some time to utilize the gliding phase. Depending on the distance and fitness the duration of this gliding phase varies. Usually the gliding phase is shorter during sprints than during long distance swimming. The gliding phase is also longer during the underwater stroke after the start and each turn. However, the gliding phase is usually the longest phase in one entire cycle of breaststroke.

Backstroke and Butterfly are not recommended for your aerobic training


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1 comment:

  1. Thật là những điều tôi đang tìm, rất biết ơn bạn về chia sẻ vừa rồi
    Một vài ý kiến tham khảo thêm: quần áo aerobic