Since I shall shortly be departing for distant shores, I wanted to be able to lay out some of my knowledge about swimming for you before I go. So when I'm lounging on the beach in Spain my wisdom will live on in Alnwick Tri Club.
SWIMMING
By John Lester
WHY AND HOW
I have often been asked “Why this drill? Why that drill?”. Unfortunately, on poolside, time is against a comprehensive answer to any question when I am looking at maybe 20 people in four separate lanes. Here I will attempt to provide a comprehensive guide to why and how.
Water, to all intents and purpose, incompressible. The harder you push against it the harder it pushes back. Which is why the harder you try to swim faster the more tired you get with very little increase in speed.
Whilst it is true that swimming is the least important discipline in terms of time in a triathlon, it is very important in terms of conserving energy for the subsequent disciplines.
If you look at the better swimmers they almost always seem to be swimming slower than you yet going faster, how? They are swimming more efficiently.
Only three things are important in swimming faster, technique, technique and technique.
Breathing
To better understand the why and how of breathing I will try to explain the mechanics, as I understand them. When you breathe in the diaphragm (a plate of muscle attached to the bottom rib ) pulls downwards, at the same time the rib cage moves outwards and upwards. Together these movements cause the internal volume of the lungs to increase inducing a low pressure or partial vacuum internally. Air rushes into the partial vacuum to equalise the pressure this is how we breathe). Once in the lungs the air enters the alveoli (small grape-like chambers) which have a one-cell thick, semi-permeable membrane. This membrane is so fine it holds blood but is porous to air.
To breathe out the diaphragm relaxes and moves upwards, the muscles in the rib cage relax allowing the chest to fall, increasing internal pressure and squeezing out the CO2 rich air. This exhaling is a largely passive, usually requiring no effort at all except during exercise. When your face is in the water you have to consciously push air out against the water. This in itself is tiring until you develop your breathing-out muscles.
The desire to breath is normally controlled by the autonomic system, which controls all the unconscious or automatic bodily functions. The trigger for the desire to breathe is the increase of CO2 in the blood/lungs, an area of the brain called the carotid body monitors this increase and triggers the breathing cycle. Whilst swimming you take over this automatic response and control your breathing to fit the swimming stroke cycle. By delaying taking a breath, over time, you condition your body to cope with the deficit (hypoxia) whilst maintaining your performance. Training your body in this way it will actually produce more blood and more haemoglobin to cope with the demands placed upon it. This is a similar effect to training at altitude, where the partial pressure of oxygen is less, forcing your body to produce more haemoglobin (the oxygen carrying part of the blood). An increase in blood volume and haemoglobin content increases your potential energy output. Haemoglobin in the blood is the oxygen carrier.
More blood, more oxygen uptake, better performance.
To understand the physiology of breathing it is first necessary to understand partial pressures. Air comprises roughly 20% oxygen 80% nitrogen (true there are trace elements of many other gases including carbon dioxide (CO2) but for our purposes 20/80 is near enough).
So 1/5 of air is oxygen (O2) which we need and 4/5 Nitrogen (N) which is not used in metabolism and can be considered inert for our purposes.
If you had a pint glass full of air and the air was separated into its different parts the beer would be the nitrogen and the head on the pint would be the oxygen (rather a big head).
So every time you breathe 4/5ths of what you breathe in is not used at all to support life.
The body uses oxygen using it to release energy in a process called respiration. The by product of this process is Carbon Dioxide (CO2) and it needs to be removed from the body, via the lungs, by breathing.
The air you inhale contains 20% oxygen. The blood on the other side of the membrane contains 16% oxygen; the 4% difference is made up of carbon dioxide, a by-product of metabolism. Your body has used 4% of the oxygen to meet its energy requirements (the harder you work the greater your oxygen/ energy requirements). A gaseous exchange has taken place across the membrane. Oxygen from the lungs crosses the membrane into the blood to make up the short fall in O2, whilst CO2 leaves the blood and enters the lungs and is exhale with the next breath.
By delaying breathing your body becomes more efficient at using the available oxygen. The body has physical limitations and will only let you push it so far in controlling your breathing. If you attempt to exceed these limits with breath-holding, or hyperventilate (rapidly breath in and out prior to breath holding) in a desire to go longer without breath there is a danger you will pass out. The reason being that the residual volume of air always left in the lungs (however hard you breathe out) contains a high % of CO2 and the carotid body monitors this with high CO2 levels triggering the breathing response. If you hyperventilate you flush out this CO2 and before the partial pressure CO2 is high enough to trigger the desire to breathe you may pass out. On dry land this is not such a problem, You fall over if you are standing up. Even when unconscious your body still metabolises O2 so eventually you start to breathe again and regain consciousness, if this happens whilst you are in water you begin to breathe whilst still unconscious and drown.
Breath holding is normally safe as long as you have not hyperventilate prior to holding your breath.
So, by controlling when and how you breathe your body adapts to and makes better use of the available oxygen. Your body becomes more efficient in its use of oxygen enabling you to swim faster, for longer, if your technique allows.
You can now buy resistance breathing devices which you stick in your mouth and forcibly breathe out against, these are sold as an aid to training or as an aid to asthma sufferers. Just practicing freestyle swimming will have a much more beneficial effect on lung function. One member of the Tri-club was on medication for asthma for years. After one season of freestyle swimming the medication was no longer required and Vital capacity and peak flow were greatly increased.
Various medical terms are used to describe lung function.
Vital Capacity – a measurement of how much air you can expel in one breath. Residual Volume – the amount of air left in your lungs after breathing out. Peak Flow – the speed at which you can breathe out.
Vital capacity and peak flow increase over time with regular exercise.
With this increase your performance at swimming, cycling and running will improve.
Cycling and running performance will improve over time with more effort. The harder you try the faster you go.
Not so with swimming. Unless you swim more efficiently your higher fitness levels will be largely wasted.
WHY DRILLS?
Drills
If you repeat a movement often enough it becomes automatic you are not consciously aware of what you are actually doing. You are only aware of the end product.
How do you ride a bike ? you just get on it and “ride”.
How do you swim?
More importantly how do you swim faster? Unfortunately it is not quite so simple.
Try Harder? Water is incompressible press harder it presses back harder. You go no faster just get more tired.
Drills are designed to help you become more aware of the track of your limbs through the water, and air, helping you to swim more efficiently.
By exaggerating or overcompensating the track of your limbs or body through the water your “proprioception” (awareness of the position of your body or limbs when out of you line of sight) improves. When you return to full stroke swimming the track of your limbs has been modified by the drill.
For example if you perform chicken wing or zip drill the track of your arm during the recovery phase of your stroke is altered your elbow is higher and your shoulder more relaxed. Although initially it feels strange, when you return to full stroke swimming the track of your arm will have changed, hopefully for the better.
The reason for a coach on pool side is to provide you with feed back on your attempts at the drills.
The big problem when you are swimming is that you get no visual feed back on your body or limb position during the stroke.
The coach provides that feed back.
The reasons for the various drills are listed below.
Breathing every third stroke. Mechanically it makes a lot of sense It keeps the stroke symmetrical, helps to prevent extensive roll of the body to one side, helps to avoid RSI problems with the neck, and lets you keep an eye on competitors on either side of you.
In open water and sea swims it can be crucial in avoiding a mouth full of water every time you breathe. If waves are breaking on the side you normally take your breath how are you going to be able to maintain regular breathing?
How much easier to have the ability to change your breathing cycle at will?
Breathing Every 3rd, 5th, 7th, Stroke. Supposing you are swimming in open water and you turn to breath and either find water where you are expecting air, or a competitor baulks you and you miss a breath, are you going to stop to get your breath back? Why not practice missing the odd breath and learn to carry on. The other reason for this drill is that, over time, your lung function will improve and you will be able, when breathing normally, to maintain a higher speed with less fatigue.
Catch Up Teaches you to always stretch to the front of the stroke and increases stroke length when you revert to your normal stroke. The down side of this drill is that you decelerate whilst the hands are together and accelerate on the pull, making the stroke disjointed.
Chicken Wing , Finger trail, Salute. All drill that encourage a high elbow are to help with a smooth recovery of the arm to the front of the stroke and a high elbow on the pull. A high elbow on the pull means that the forearm as well as the hand catches the water. The better the catch and pull the greater distance per stroke
Stroke Count / DPS If you can reduce the number of strokes you take to cover any given distance whilst maintaining speed you must be swimming more efficiently. Less strokes means less energy used per metre swum. DPS (Distance per Stroke) is another way of reducing stroke count. If you focus on length of stroke your stroke count will decrease. Over time you will adopt a longer stroke, and become more efficient at swimming enabling you to swim faster with less effort.
Try to keep it simple.
If the body is flat on the water, ie hips up, any application of force will result in forward motion. Many swimmers find they can swim as fast or faster when using a pull-buoy than when swimming full stroke. The reason being that the hips and legs are higher in the water (body flat) so the force generated by the arms is used more efficiently.
As the hand enters the water at the front of the stroke fingers first followed by wrist, forearm and elbow. The elbow stays high, the fingers and forearm “catch” the water.
The back of the hand points the way you want to go, pull the body forward until the arm is past your waist then push until your hand touches your thigh and begin your recovery.
Forget about ‘S’ shapes, just keep the elbow higher than the wrist at all times.
Good Luck
The Old Git
"Death is just God's way of telling you to slow down"
Edited by John Lester on 07-08-2007 21:18
