Bilateral Breathing (alternating to both sides) is not the only solution despite what the text books will keep telling you. Until you have control of the breathing aspect of your FrontCrawl (F.C.) stroke it will also not be possible to relax in the water regardless of how often people keep giving you this advice. How often, for how long and when is one of those grey areas that is quite individual to you. The right and wrongs though would include in through the mouth (only) and out when the head is submerged. Don’t wast time exhaling when the head is turned to the side. The best solution is what is comfortable for you and depends if you are racing or training and at what intensities. Usually on race day that means each second stroke to keep a healthy flow of air coming into the body. In training however it would be good to mix the pattern to stop any bad habits becoming ingrained. This could include alternate lengths swapping sides. If you struggle to breath to a certain side check your technique for balanced and symmetrical rotation. A lack of rotation to a certain side will impact the heads ability to turn. Try the Torpedo drill to assist here. If the head only turns to one side repeatedly then there will be negative repercussions to body position and arm movements. We always try to balance particular movements so that they are not repeated on their own too many times. Keep in mind the head is a large clumsy object that contributes so much more to fast swimming if it does not move. Keep head movements when turning to breathe, small, fast and fluid.
Some coaches will suggest a full exhalation at the last moment before the head turn to keep the body high in the water, others will feel that this added buoyancy to the chest cavity will keep the legs low so to exhale continually. There are arguments for and against both styles but reducing anything that causes tension is desired (so exhale a small amount continually during the face in the water stage) and if you’re legs sit low find out why, there are probably contributing factors.
A breathing pattern (B.P.) alternative I like is the 3.2. Here you take 3 strokes between breaths then 2 so it mixes 2 breaths to the left then 2 to the right. You could think of this as 2 breaths per 5 strokes rather then 6 which is slightly less taxing on the system. I try to encourage bilateral breathing (to both sides) at low intensities in training (warmups and subsets, even cool downs.) A key piece of swim equipment to help is the central snorkel that takes the head movement for air out of the equation altogether meaning you get a chance to focus on body position and arm movements. Getting comfortable with the breathing aspect of FrontCrawl is not easy but once mastered will allow you to relax in the water and start to make some big gains. Early on the stroke will dictate when you get to breathe (compare to the bike and run when you are always in charge) which will never allow you to relax. As stroke mechanics improve you will take charge of when you breathe and so allow the stroke to be performed more relaxed. A more relaxed stroke is less aggressive, more economical, needs less air and the delicate balance of pulling on slippery nothingness gets easier.
One of my favourite blocks of work to reinforce these concepts is as follows. Perform a sensible warmup ahead of starting this more intense block of work. Consider this your main set which should then be followed with a cool down. B.P. – Breathing pattern. A breath every 2nd,3rd, 4th or 5th stroke etc. Rest 25 between each swim. FC – front crawl swimming stroke
500metres (20Lengths in a 25m Pool) F.C. (front crawl), swum with fins, Breathing Pattern 5
400metres (16Lengths) F.C., swum with paddles, Breathing Pattern 4 (change sides with each length)
300metres (12Lengths) F.C. pull, Breathing Pattern 3.2
200metres (8Lengths) F.C. swim, Breathing Pattern 2
100metre (4Lengths) F.C. swim, 3-4 breaths per length, your choice where you use them… 1500m