Effectively Training the Energy Systems
By Doug Huestis
Head Coach Bay Masters


If you are like many Masters Swimmers the swim practices you attend are an end unto themselves. That is they the serve the primary purpose of 'burning calories' as well as serving as a 'relief valve' to help you deal with the stresses of our increasingly hectic lives. And, of course, swim practices are a great 'low-impact' aerobic activity done in a social setting with other like-minded individuals.

But let's say you regularly swim in Masters swim meets, not only because you enjoy the competition, but also because you also use the times you record in those races to evaluate the effectiveness of your training program.

Take this short 'quiz' ---- if you answer most of the questions affirmatively, you may want to read this article.

1) For your 'best events' are you only a little bit faster in swim meets than what you have done in practices? YES or NO

2) Do you do on a regular basis, as an example, 12 x 200's Free on 2:30 -- holding your repeats between 2:15-2:18 -- and then think "one fast 200" in the meet should be easy -- only to wonder why you 'really tightened up' the last 50-75 yards? YES or NO

3) Try as you may you can never 'take out' the race any faster, no matter how hard you try? YES or NO

4) For the 'Open Water' swimmers out there -- do you find yourself wishing you had another "gear" you could shift to -- in order to breakaway and/or move up to the pack ahead of you? YES or NO

Energy Metabolism Summarized

In its simplest form swimming involves the repeated contraction of those muscles used to propel you up and down the pool or across the lake. Your muscles need a constant supply of energy to accomplish this. That energy is supplied by the breakdown of Adenosine TriPhosphate (ATP), which is stored in all muscle cells. ATP is, in turn, replaced by two other chemicals found in the muscle cells; Creatine Phosphate (CP) and Glycogen.

The first two chemicals, ATP and CP are known as the 'high energy phosphates' -- their breakdown releases a lot of usable energy for forceful muscle contractions. However, the energy they release comes at a 'cost'-- rapid depletion-- and after the first 25-35 yards the body must turn to another 'energy pathway' to continue at high rates of speed.

The next most rapid source of ATP replacement is Anaerobic Metabolism, or the breakdown of glycogen to lactic acid. The downside of this chemical reaction is that it involves several more chemical reactions and thus slows down the replacement of ATP, the result being a loss of swimming speed. The other more familiar result is that through the accumulation of lactic acid, blood pH drops (becomes more acidic) and interferes with effective muscle contractions, as well as producing the well known 'lactate burn'.

Finally, the body will turn to Aerobic Metabolism to replace muscle ATP stores through the breakdown of glycogen to carbon dioxide and water. While this is an even slower chemical process, and as a result yields slower sustainable swimming speeds -- it is the most efficient and economical method of replacing ATP molecules. It not only generates much more ATP molecules, it does so with minimal accumulation of lactic acid as lactates may be converted back to a more readily usable energy forms or processed via direct oxidation.
The Three Basic Forms of Training

Taking the above information it follows that to be able to swim at your best all swimmers need to adequately train the three energy systems described. Again the forms of training are:

1) Aerobic Training -- the foundation for the two other training forms. Needed to be able to swim the 'middle portion' of your races at the fastest and most efficient pace.

2) Anaerobic Training -- this form of training enables you to 'bring home' your races faster. Effective training in this energy realm allows you to shift gears and really sprint to the wall at the end of your race.

3) Speed or Power Training -- this will allow you to be able to 'take out' your races faster and generate more powerful starts and turns. Needed to enhance the release of more 'high energy phosphates'.

Aerobic Training

This form of training is needed to enable the swimmer to swim at the fastest possible pace without the accumulation of lactic acid. The bulk of training should be somewhere between the 'Aerobic Threshold' -- that being the minimal training speed that will facilitate the improvement in aerobic endurance; and at the upper end the 'Anaerobic Threshold' -- which is the maximum speed one can swim aerobically. However, for maximal adaptations' one should also include some swims that really stress ones aerobic metabolism, these would be swims of a Maximum Aerobic Effort (VO2 MAX effort).

Thus there are three types of training of the Aerobic Training:

1) Anaerobic Threshold Training - also called 'A.T. pace 'training. The speed for this type of training is as fast as possible while swimming aerobically -- think of your pace on the "one hour swim" -- swum at an 'even paced mode'. You basically cannot swim at a pace faster than your best aerobic pace for the hour swim.

Interestingly, swimming at speeds in excess of this speed has been found to be less effective in creating maximal aerobic endurance capacities .

This is of particular importance to some excessively goal driven ('no pain - no gain') Masters swimmers and quite a few triathletes. This is due to the rapid influx of lactic acid inhibiting the adaptations of aerobic metabolism. One ends up with inefficient and ineffectual training of both the aerobic energy systems as well as the anaerobic systems.

It is recommended that 50% of a swimmer's aerobic training yardage be at this level. Repeat distances are suggested to be of a distance that allows nonstop, even paced swims of 3-6 minutes of duration (i.e., 300 - 500 yard repeats). The set itself should take 20-30 minutes to complete, and the rest intervals should be minimal (apx. 10-30 seconds). If you find your 'repeat times' falling off by more than 4-6 seconds per swim on those 300's or 400's or 500's -- you are probably going at too fast a pace.

2) "Cruise Speed" Training -- This level of effort is useful for those days when you need a bit of a rest. To be effective it needs to be at a level just above ones' Aerobic Threshold, usually at about 70-75% of maximum. Efforts are moderate; one should feel as if they could pick up the pace at any time. This type of training is invaluable for energy replacement and restoration of homeostasis. I like to refer to it as the "backing and filling" of ones' aerobic conditioning.

Repeat distances can be of any length, though distances of 100 to 300 yards are best, and with rest intervals being on the short side (5-20 seconds). Repeat times will be, depending on your aerobic condition, 3-5 seconds slower per 100 yards than your A.T. pace. The set should take 15-30 minutes to complete. Approximately 25% of ones aerobic yardage should be swum at these speeds.

3) Maximum Aerobic Effort -- This type of training (also called 'VO2Max' efforts), while being stressful due to the large amounts of lactic acid produced concomitant with significant amount of muscle glycogen depletion, is needed to provide the stimulus to push ones' aerobic conditioning to the highest levels. However, due to the demands of this training form it should only account for, at the most, 25% of ones' aerobic distance training.

Repeat distances are recommended to be 100 to 400 yards, and due to the demanding nature of this training the total set length should be shorter than the other two aerobic training sets . Suggested duration for the entire set would be about 12-15 minutes depending on ones conditioning level. Rest intervals should be between 30 seconds and 1.5 minutes to allow the faster repeat speeds. Repeat speeds should be 3-5 seconds faster per 100 yards than your A.T. pace.

Training Tip:

A practical test to determine where one's individual aerobic conditioning needs are can be done while swimming a Maximal Aerobic Effort set.

Say the set is 4 x 400 repeats with 1.5 minutes rest -- each swim done with a near-max effort. If you know your own personal maximum Heart Rate (HR) you will want to have it reach at least 90% of maximum after each swim.

Be sure to take your HR immediately after each swim. Then wait 30 seconds and take it again, repeat 30 seconds after that (i.e., 1 minute after each swim).

Calculate 60% of your personal maximum HR.

If, on average, your HR drops from near maximum after each swim to below that 60% level in less than 30 seconds -- your aerobic energy systems are probably 'maximized'.

It would be more productive to spend more time on 'event/race' specific training. And use Anaerobic Threshold and Maximum Aerobic Effort type sets only to maintain your level of aerobic conditioning.
If, on average, it takes your HR 30 - 60 seconds to drop to the 60% level you need to work on improving your top end aerobic conditioning.

In this case you should use A.T. pace training sets predominantly for your main sets. A set such as 20 x 100's Free with 10 seconds rest at one's fastest even - paced speed is a good one to test/monitor positive shifts in ones' Anaerobic Threshold.

If, on average, it takes more than a minute to drop your HR to below the 60% level you need to work on basic aerobic conditioning.

It would be counterproductive to try to do Maximum Aerobic type sets. The bulk of all your training should be between "Cruise Speed" and A.T. pace mode. Also high intensity anaerobic training should be minimal.

Anaerobic Training

This type of training can yield big dividends if done properly. Basically you are trying to train your body to 'deal' with the discomfort of increased levels of lactic acid and the resultant drop in muscle pH. You also can train your body to increase the production of lactic acid (yes, it is an energy source), as well as enhancing your muscles ability to both buffer (think how TUMS work on stomach acid) and to re-synthesize lactates (key point: Lactate Clearance Rate).

If you can train your body to produce lactic acid faster and in larger quantities, yet also buffer and clear it out of the working muscles more efficiently you should be able to sprint longer and faster at the end of your race.

However, as in many other things 'moderation' is the key. Do not attempt to do all forms of Anaerobic Training on a daily basis -- not only will it become counterproductive, it could also be dangerous especially if you have not built up a solid aerobic foundation first!

From the above information we have two types of Anaerobic Training:

Anaerobic Endurance Training -- The main emphasis of this type of set is to facilitate the production of lactic acid.
The repeat distances should be in the 50 - 200 yard range with rest intervals of 15-60 seconds. Speeds should be at 85-95% of race pace and near maximum heart rates should be expected. This should produce very high levels of lactate. The set itself should be only long enough to allow maximal quality efforts (no more than 600-800 yards).

Broken swims are a variation of this training form. A set such as 3 x 200's with 1 minute rest; with the 200's broken as 4 x 50's with 10 seconds rest at near race pace not only helps enhance your lactate tolerance, it also helps hone your pacing skills.

Anaerobic Power Training -- This form of training is predominately geared toward increasing your muscles ability to buffer and re synthesize lactic acid.

You should swim very, very fast repeats (95-110% of race speed) with long rest ("minutes"). Repeat distances are short, 50 to 100 yards. The use of short recovery swims (25's) at 50-60% effort is recommended. The total length of this kind of set is only 300-400 yards.

A favorite set of this type is 3 or 4 times through the following:

5 x 25's EZ/ Free on :30
30 seconds extra rest
1 x 75 Sprint/ Major Stroke on 2:00

Speed Training

The main purpose of this kind of training is to improve your ability to take races out faster and more efficiently.

Repeat distances are very short, 5 to 25 yards. Speeds need to be much faster than race pace to be effective. The entire set should be 100-200 yards long. Recovery time is long -- long enough to not allow any accumulation of lactic acid.

Insufficient recovery time will defeat the purpose of this kind of training -- that being the facilitation of maximal muscle recruitment. You should only feel a mild feeling of lactic acid induced discomfort.

This type of training is also enhanced by 'speed resisted' work (Power Rack, swimming out against surgical tubing), as well as 'speed assisted' work (fins, "snap-back" surgical tubing).

Be sure to do the major strokes you will be competing in order to facilitate maximal adaptations in those specific muscle fibers. This is also a good set to do "explosive starts" off the blocks with half or full length sprints on long rest.

Armed with the above information you should, by putting it into practice, be able to 'convert' your old style one speed training body into a finely tuned five or six speed racing machine.

Train to train or train to race -- the choice is yours!!


Doug Huestis coaches Bay Masters (BAY) in San Francisco. He has served as a member on the USMS Sports Medicine Committee, where he authored numerous articles on 'Swimming Physiology and Training.' He holds a Masters degree in Exercise Physiology, and was Head Masters Coach for The Olympic Club (1990-1997) where his swimmers broke over 225 Masters National and World Records and won 4 USMS National Championships and 2 FINA Masters World Championships

back to Coach Doug’s Corner