Tag Archives: zone training

HOWTO: Discussing Zone Training

In HOWTO Write a basic training system, I said we would progress from the structure of a simple one hour or more training system to devising a more comprehensive swim training plan.

A long time ago I wrote a post on introducing interval training to swimming and another on heart rate zones, that one really only included the chart below with little further explanation.

To progress in this area, we need to talk about the different types of training. The Zone System in the chart mentioned above is one way of categorising training types.

There are four or five zones depending on your preference or how you categorise them. First below is the five zone system.

Heart rates and rest intervals increase with Zone number and set distances decrease.

Zone 1: Aerobic, sometimes called endurance or even recovery. This is where swimming can be maintained with available oxygen and only low levels of lactic acid will be produced with which the body can cope or dispose. To complicate this mess of terms, Zone 1 is further subdivided into three types, recovery, maintenance and stimulus. The different types are defined by heart rate below maximum heart rate, from 70 to 30 beats below maximum. For distance open water training, e.g. training for a first 3, 5 or 10 k swim. For simplicity it’s easier to divide aerobic into recovery (easy, 50 to 70 beats below maximum), and endurance, (30 to 50 below maximum). A majority of swimming is done in the endurance zone. Strictly however, recovery is the lowest rate of aerobic training, what an experienced swimmer would categorise as very easy, or easy, at 60% to 70% maximum heart rate. Rest intervals are short and set distances can be long.

Zone 2: Anaerobic Threshold. This is where lactic acid (lactate) accumulates more quickly than the body can dispose of it. Heart rate is higher, 20 to 30 beats below maximum.

Zone 3: High performance (or Critical Speed) Endurance. This can also be called heart-rate training. It’s usually marked by increasing effort through the set, not starting too high but increasing in speed and intensity. This is the origin of a typical descending set, where times reduce and speed increases through a set, like Paul Newsome’s Red Mist set of repeating 400s. Rest intervals are longer than anaerobic threshold, from 20 to 30 seconds with heart rates 10 to 20 beats below maximum.

Zone 4: Anaerobic. Also known as race pace training, and not to be confused with Zone 2. This is commonly known also as lactate training. For most open water swimmers, this training comprises longer distances and requires longer rests. You should realise that race pace is NOT the same as sprint. The body is learning to tolerate lactic acid, and also to delay its production.

Zone 5: Sprint. This is maximum speed training and can only be performed over very short distances with long rests to stop lactate building up otherwise it becomes Zone 4. Heart rate is maximum.

One thing that can easily be noticed is the lower the zone number, the longer will be the swim distance, and the shorter the rest interval (swim long, rest short is the maxim). Obviously sprints are short distance, and long distance must be sustainable.

Using heart rate to control exercise
Using heart rate to control exercise

An alternative to the five zone system is a four zone system. This is essentially the same and just uses easier to communicate names and is based more on RPE, which is the swimmer’s Rate of Perceived Effort. Some coaches will explicitly tell swimmers to swim a set at 75% or 85% or 90% RPE. 

I’ve found when explaining this, that it is important to explain that really easy swimming is about 65% of maximum heart rate. People new to exercise often think that really easy effort is more like 10% or 20%. If you use a casual ambling walk for comparison, that will still be 60 to 65% of maximum heart rate.

Your maximum heart rate drops with age, and a rough rule of thumb, (which can be justifiably criticised) is that 220 minus your age is your maximum heart rate. There are many individual variations to this.

Recovery Zone: 60% to 70%. Lowest heart rate training. This maximises fat burn and comprises long unbroken sets with short rest intervals. This is basic endurance and heart rate training. It is  also used to recover from racing, sprinting or higher level exertion.

Aerobic Zone: 70 to 80%. This zone is where much of your endurance and cardiovascular fitness comes from. Some fat is used for energy in this zone.

Anaerobic: 80% to 90%. Long distance swimmers will do a lot of training in this zone, which build up tolerance to lactic acid. However lactate buildup will eventually overwhelm the ability to perform further. Also, all energy is coming from the body’s ATP (glycogen) system and is therefore time limited.

VO² Max (Sprint): 90% to 100%. This area is for pure speed only and in only possible for a short time. The first few seconds of sprint are partly powered by creatine produced in the body, which only lasts for effort under less than 10 seconds.

In spring 2013, Evan Morrison and I collaborated on some training tips specifically for triathletes. Amongst his many excellent points, one that Evan made and noticeable in many pool lap swimmers, was that many people just swam continuously at one speed.

A rounded swimmer, or one training for an event, should be training in all different zones and at different speeds.

In the next part we’ll look at combining the different zones into a larger plan.

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HOW TO: Introducing interval training to your swimming

First, Happy Imbolc, the Celtic first day of spring, more commonly known as St. Brigit’s Day and also known as Candlemas.

Pool and marathon swimmers use intervals to train. One of the regular misconceptions we come across is the belief that our training involves lots of slogging up and down the pool whereas we train the same as normal pool swimmers using intervals as the basis for everything.

So, how do you work out your intervals? well, one way is experience, I know the times to within seconds that I want to hit depending on what I want heart rate or perceived effort I want to exert and recall I posted a chart of heart rate last year. But in the absence of that experience, you can use an interval calculation chart.

But first we need to go back a bit. USMS posted a nice fitness pace chart, useful for calculating estimated times from a 100 metre (or yard) time to help establish pace from a known short distance time.

I’ll loosely define Cruise Speed as the speed you can maintain, with a few seconds left over at the end of each repetition.

On the first table, say your 100m Cruise Speed is 1:45. You will have 5 to 15 secs left over. If you have more than 15 secs your cruise speed is probably 1:40 or 1:35. If you have less than 5 secs left over, your cruise speed is 1:50.

Look at the 1:45 row. So for 200 metres, your pace means you should finish within 3:30. For 400m, it 7:00…and so on. A 1:45 swimmer should be able to do 3,425 metres in an hour, cruising.

(This table does not tell you what your time is, you should determine that yourself.)

USMS Fitness Pace Chart

But for actual interval training you need a bit more. A couple of years back I took an older interval chart and put all the times into a spreadsheet to make it more usable, it’s below.

Measure your Personal Best for a distance (e.g. 100m) and let’s say it is 1:45. Look at this figure in the leftmost column. Now look along the row to the right. This means that your 85% (Moderate) repeat is 2:08 to 2:15. which should include a few seconds rest before the next repetition (100m).

Put this together with the heart rate Zone training chart and you have the basis for building swim sets according to requirement, whether speed, endurance or weight reduction.

Edit: I should make clear, this is an introduction to interval. Therw is more the subject than this, particularly session planning.