Front crawl is the fastest swimming style to quickly reach a casualty. However, when swimming fully clothed front crawl is only a bit faster then breaststroke, and costs more energy. Fit lifesavers can do the head-up front crawl with all their kit on, a good training goal.
In lifesaving, the head is often kept out of the water. The head-up crawl allows rescuers to keep an eye on their casualty, at the price of a much steeper body position and higher drag. Hence a compromise is to look at your casualty every 4 seconds or so.
The swimming position on the front allows full use of the arms in the water. The above-water recovery reduces drag, compared to the underwater recovery of breaststroke.
The alternating arm stroke also allows some rolling movement of the body for an easier recovery compared to, for example, butterfly.
Finally, the alternating arm stroke makes for a relatively constant speed throughout the cycle.
Front crawl often starts with a shallow dive from the poolside. The skill lies in finding the right balance between going in too deep and a belly flop.
Shallow diving can cause serious injuries if you hit the floor with a deep dive. Minimum water depth must be 1.5 metres, maximum freeboard about 0.4 metres. On the other hand, a belly flop can hurt your skin, unless you wear some clothes, which we would advise for initial training.
The arm movement for front crawl is alternating. While one arm is pushing/pulling, the other arm is recovering, moving forward. The arm strokes provide most of your forward movement and can be separated into four parts:
Stretch one arm for forward, reach out. Use your 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.
From this position, the arm sinks slightly lower and the palm of the hand turns 45 degree with the thumb side of the palm towards the bottom.
This is called catching the water and is in preparation for the pull.
It also gives the muscles a brief rest during swimming.
The pull movement follows a semicircle with the elbow higher than the hand and the hand pointing towards the body centre and downward. This semicircle ends in front of the chest at the beginning of the rib cage.
At the beginning of the pull, the hand acts like a wing and is moved slower than the velocity of the swimmer (this may look like a brief rest) while at the end it acts like a scull and is moved faster than the velocity of the swimmer.
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.
The movement increases speed throughout the pull push phase until the hand is moving at its greatest speed shortly before the end of the push.
Sometime after the beginning of the recovery of the one arm, the other arm begins its pull. The recovery moves the elbow in an almost vertical semicircle 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. This gives the muscles a brief opportunity to rest.
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. You may want to practice that. Put on a pair of jeans and lie on your front in knee deep water. Now practice pulling a hand out of the back pocket and move it past your ear forward.
Further into the recovery phase, the hand movement has been compared to pulling up the back 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 into the air while the other is jumping 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.
Inhale during arm recovery. Keep your hand relaxed below the elbow.
Beginners often don't relax the arm during the recovery and move the hand too high and too far away from the body, in some cases even higher than the elbow, hence drag and incidental muscle effort is increased at the expense of speed.
Normally, the face is in the water during front crawl. 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. The head is turned 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 avoids water entering the nose.
Some swimmers take a breath every cycle, with every second arm recovery, breathing always to the same side. Since breathing slightly reduces the speed, most competition swimmers breathe every 1.5 cycles. Lifesavers sprinting the last few meters to a casualty may breathe even less.
This is a useful skill for open water swimming as well as pool training. It simply means to be able to breathe on either side.
When you swim in open water with waves you can breathe away from the waves. If you switch sides often you can keep an eye out for where you go and what happens around you. Many pool swimmers who are used to lines on the bottom, tend to go around in circles if they don't look out.
This skill is helpful for pool swimmers as they can adjust their breathing to their speed, instead of breathing every cycle or two, they can breathe in between or whenever they need to. Practise this until you get really good at it.
A training 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 less strength for swimming. This is because the immersed length of the body is longer and more streamlined. This style is slower than the regular front crawl and is used for training purposes even by professional swimmers, as it increases the your awareness of being streamlined in the water. Total Immersion is a similar technique.
The leg movement is called the "Flutter Kick". Ideally, there are 6 kicks per cycle, although it is also possible to use 4 kicks or even 2 kicks.
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 stabilise the body position. If you use a pull buoy, then you will see the lack of balance, because you are not using your legs.
The leg in the initial position bends very slightly at the knee, and then kicks the lower leg and the foot downwards similar to kicking a football. 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.
The body rolls about its long axis with every arm stroke such that
the shoulder of the recovering arm is higher than the shoulder of the pushing/pulling arm.
This makes the recovery much easier, reduces drag as one shoulder is out of the water, and reduces the need to turn the head to breathe.
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.