On the Why Test? page you read,

"The really, really useful information of lactate testing shows you the changing relationship between effort and speed - at the low intensities the speed increases faster than the lactate; at the higher intensities, the lactate changes faster than the speed."
la-vel. graph K.I.S.S.

In every coaching or scientific publication you see the, now familiar, lactate-velocity curve, which attempts to simply illustrate this point.

However, for many coaches, it is not simple; the challenge is to read any changes in the curve and interpret their message accurately. Only then can the test data show you how valuable it is.


You have learnt that the three vital components of sporting performance are :

1. Endurance; the velocity during, predominantly, aerobic work - for illustrative and comparative purposes, we have chosen the time at a velocity producing 4mM of lactate (tV4), for our standard value.


2. The lactic acid value at Maximum effort.


3. The Power-relationship between these first two components.

Each of these components combine to produce the Race Time, illustrated by the time at a velocity producing LaMax. Each of them can also change, depending on the training input. Graph 2 illustrates these possible changes.
graph2 Change: the only constant

Changes in Endurance are seen as a change in the position of the curve, to the right or left. This movement is usually noted in the lower part of the curve - right for improved endurance, left for a deterioration.


Changes in the lactic acid value at Maximum effort (LaMax), are seen as movements in the height of the curve. When the line is higher the lactate level is higher.


Changes in the relationship between endurance and LaMax, are seen as a change in the shape of the curve. This reflects the applied Power. A "flattening", or diagonal, downward change to the right, illustrates more applied power, a "steepening", or diagonal, upward change to the left, illustrates less applied power.


Real world data

All the illustrations here are taken from actual test results, using a series of 200m swims of an individual swimmer, over a period of years. Sometimes the results are used out of the real time sequence in order to better illustrate a particular change, but the actual changes are real; they can, and will, happen to your swimmers. The scale of the graphs is kept constant; the only "visual" or statistical trick used is that, in some instances, I have equated the race speeds so that the other changes can be clearly isolated. The values, or numbers, both in lactate and velocity, have been omitted from the graph axis, as their presence merely adds irrelevant "noise" to the message - changes in velocity are much better illustrated by pictures than by numbers. The significant data, tV4, LaMax and Race Time, is shown below each graph so that you can judge the magnitude of change and relate the information to the real world - the change from 2:44.86 to 2:37.92 is much easier to comprehend than a change of velocity from 1.213 m/s to 1.266 m/s. At least it is to me.


tV4 2:32.02 2:25.08
LaMax. 16.7 16.7
Race Time 2:10.47 2:05.90


Graph 3 shows an improvement in endurance, illustrated by a change in position of the curve. The change is to the right. The change can be due to an improvement in any of three factors:

Aerobic metabolism - more aerobic energy available per unit of time

Technique - the swimmer will use their available energy to better effect and the stroke-count will have dropped.

Streamlining, causing less drag - the swimmer will move faster with the same energy-use, or at the same speed with lower energy use.

Whatever the cause it is still an improvement in endurance - the ability to repeat or sustain exercise.

If single, low-intensity swims are compared from test to test and the swims are similar in speed, it can appear that the result is a downward change in curve position. This is misleading; the swimmer is using less anaerobic energy, therefore either the same or more aerobic energy, to swim at the same speed - it is an improvement in endurance and the curve has moved to the right.

If no other factor changes, then a right shift is good.


tV4 2:32.02 2:32.02
LaMax. 13.2 16.7
Race Time 2:13.57 2:10.47

Lactate Maximum

Graph4 shows an improvement in LaMax., illustrated by a change in height of the curve. The change is upward, showing that the swimmer produced more lactic acid to achieve the performance. As the graph line curves continually to the right, any increase in LaMax is an increase in speed. The cause could be an improvement in anaerobic metabolism, with the swimmer generating more energy with the same effort, or motivation, with them using more effort to generate more energy - the swimmer worked harder and pushed the curve higher.

If no other factor changes, then a higher maximum is good.


tV4 2:32.02 2:24.15
LaMax. 16.7 16.7
Race Time 2:10.47 2:01.87

Applied Power

Graph 5 shows an improvement in the relationship between tV4 and LaMax; an improvement in applied power, illustrated by a change in shape of the curve. The change is a "flattening".

Improvements in applied power can arise through improvements in:

Technique, or Control of existing technique

Muscle power, allowing greater acceleration during the propulsive phase of each stroke. This increased power could be caused by either increases in :

strength - either an ability to produce muscle tension, or intra-muscular coordination, or

speed - inter-muscular coordination.

Whichever power aspect is improved, it must be applied power.

If no other factor changes, then a flattening is good.

No vital component is an island

These three components do not exist in isolation; a change in any one of them, will affect the other two. A change at any point of the curve will affect every other point on the curve. This is a "catch-22" situation for a coach as, when you design a program to develop, say, aerobic endurance, you cannot escape the consequent changes which will occur to the maximum lactate and power components. This is because training for aerobic development will ensure that time is "lost" to anaerobic development and some anaerobic, muscle-fibre characteristics will change. Because of the aerobic training, the anaerobic characteristics of the curve will change. This is the basis of training periodization.


Obviously, if components cannot be developed in isolation, they should not be interpreted in isolation. This is the mistake which most coaches, and scientists, make; they will observe a positive change in one component and infer that everything is fine. Or, conversely, observe a negative change, and infer that everything is a disaster. Either may be true; but, equally, either can be totally untrue. The whole picture has to be seen and understood before an accurate and useful diagnosis or prediction can be made.

The truth, the whole truth

Graphs 6, 7 and 8 illustrate the various combinations of changes which are possible :


tV4 2:32.02 2:31.27
LaMax. 16.7 16.7
Race Time 2:10.47 2:14.42

Change is bad

Graph 6 shows a small improvement in endurance and a deterioration in applied power

The changes can be due to any of the positive factors outlined in graph 3, and any negative changes corresponding to the factors outlined in graph 5. Technique is a factor in both endurance and power, so stroke counting will determine if the swimmer changed technique during the test. If they did, you have to identify the reason - most likely lack of concentration, or lack of strength-endurance. .

The relative magnitude of the positive and negative changes will determine if the total outcome is good or bad; in this case, it is bad, but if you had tested endurance in isolation, you would arrive at a different conclusion.


tV4 2:32.02 2:37.36
LaMax. 16.7 13.8
Race Time 2:10.47 2:10.47

Change ... what change?

Graph 7 shows a deterioration in endurance, an improvement in applied power and a deterioration in LaMax., illustrated by a change in position of the curve to the left, a flattening, and a lowering of the peak of the curve.

The relative magnitude of the positive and negative changes will determine if the total outcome is good or bad; in this case, it is the same, but if you had tested any one of those factors in isolation, you would arrive at a different conclusion.


tV4 2:32.02 2:24.15
LaMax. 16.7 17.5
Race Time 2:10.47 2:00.51

Change is good

Graph 8 shows an improvement in all three components - endurance, LaMax and power, illustrated by positive changes in position, height and shape of the curve. The swimmer has succeeded in achieving the ultimate psycho-physiological-biomechanical goal - swimming as fast as possible without using lactic acid, then, when it becomes inevitable, using as much as possible and, on the way, gaining the maximum benefit from each increase in effort. The pool is full of happy, smiling people. Except the opposition!

The total outcome is very good; the magnitude of each of the positive changes will determine how good. If you had tested any one component in isolation, you would arrive at a similar conclusion, but would not realize just how good it was.


All the above compares varying situations relating to one swimmer. If you compare different swimmers there are other considerations to include. The qualities of the three components, Endurance, LaMax and Power, are present in different degrees, and developed differently, in different swimmers.


tV4 2:27.75 2:13.06
LaMax. 14.0 9.8
Race Time 1:59.99 2:05.57

All animals are not equal

Graph 9 compares typical curve shapes for a Sprinter and Distance swimmer. The distance swimmer has better endurance, less applied power and lower LaMax when compared to the sprinter. These typical qualities reflect the requirement characteristics of the different specialist events. When comparing swimmers test results for different swimmers, make sure you carefully consider the different event requirements.


Mad scientists start here

Graph 10 attempts to diagrammatically illustrate the relationship that alactic qualities have with the lactate-velocity curve. Now, you have to suspend your sense of disbelief for a few minutes as "alactic" means, "without lactic acid", and, yet the lactate-velocity curve is, by definition, measuring lactate, which is a derivative of lactic acid. So, what we have here, is a coach's way of illustrating a concept, which may have the scientists amongst you rolling under the laboratory tables howling with mirth and derision. No matter.


Alactic means "free" speed

Everything should be related to the goal, which is the race, so, in terms of race importance, the alactic capability describes the point where the swimmer can enter the curve, "for free", "complimentary", "gratis". In sprint races this is vitally important; in distance events, it is of minor significance. Distance swimmers almost have to "swim up the curve" during their race; remember, their curve is steep, so they are still swimming very close to maximum when they are low on the curve. Sprinters cannot afford to be low because their curve is flat, and low means slow (Ha!). Sprinters have to burst into their performance at the very top of their curve.

For any alactic test, a decrease in lactate, coupled with a stable speed, or an increase in speed coupled with stable lactate, is good.



Different total volume, and intensity-balance, of training programs ensures that endurance, LaMax and power capacities are developed differently in different individuals. Additionally, genetically-endowed qualities, such as fibre-typing, ensure that the starting points of those capacities are vastly different and that those qualities develop at different rates within the same training program. When comparing test results of different swimmers, these factors should be taken into account.

Some swimmers are genetically suited to one group of events, say sprint, rather than another, say, distance, so will exhibit different qualities in their total performance characteristics - this is talent. Some swimmers will show greater improvement for the same training input - this is talent. Both these aspects of talent should be considered when prescribing training programs following the analysis of test results.


Talent has been defined as,

"the combination of hereditary gifts and acquired skills."


and described as being measured by,
"the rate of improvement."

Ericsson and Charness, 1994

"the rate of improvement in the training situation."

Halberg, Regner, personal conversations.

Test results, if interpreted correctly, will illustrate the degree of each of these aspects of talent. Testing will enable you to ensure that your talented swimmers win the medals.

handy analyzer





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Published originnally March 29, 1998. All contents © Sports Resource Group, Inc.