03-19-2008, 03:31 AM
Author: Doug Huestis; Sports Publications, Inc.
Submitted: 04/02/2000
In its simplest form, swimming involves the repeated contraction of the muscles used to propel you through the water. Your muscles need a constant supply of energy for propulsion. This energy is supplied by the breakdown of adenosine triphosphate (ATP), which is a chemical stored in all muscle cells.
ATP is replaced by two other chemicals found in the muscle cells: creatine phosphate (CP) and glycogen. 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. This cost is called rapid depletion. After the first 10-12 seconds, the body must turn to another energy pathway to continue at high rates of speed.
The next most rapid source of ATP replacement is called anaerobic metabolism, which is the breakdown of glycogen to lactic acid. The downside of this chemical reaction is that it involves several other chemical reactions, which slow down the replacement of ATP, resulting in a loss of swimming speed. The other, more familiar result is that through the accumulation of lactic acid, blood pH drops, becoming more acidic, interfering with effective muscle contractions and producing the well-known "lactate burn."
The last method of ATP replacement used by the body is the process of turning to aerobic metabolism to replace muscle ATP stores through the breakdown of glycogen to carbon dioxide and water. While this chemical process is slower than the others -- resulting in slower sustainable swimming speeds -- it is the most efficient and economical method of replacing ATP molecules. Aerobic metabolism not only generates many more ATP molecules, but it does so with minimal accumulation of lactic acid.
The Three Basic Forms of Training
The preceding information suggests that your best swimming will result from adequate training of the following three energy systems:
- Aerobic Training is the foundation for the two other forms of training. It allows you to develop the fastest, most efficient pace during the middle of your races.
- Anaerobic Training enables you to finish races faster. Effective anaerobic training allows you to shift gears and sprint to the wall at the end of your race.
- Speed or Power Training allows you to be able to start your races faster and generate more powerful starts and turns.
Aerobic training enables the swimmer to achieve the fastest possible pace without experiencing the accumulation of lactic acid. The bulk of training should be somewhere between the aerobic threshold and anaerobic threshold.
Aerobic threshold is the minimal training speed that contributes to the improvement in aerobic endurance. Anaerobic threshold is the maximum aerobic speed.
For maximal adaptation, include some swims stressing the aerobic metabolism. These would be swims of a maximum aerobic effort (see Chart #1).
There are three types of aerobic training: anaerobic threshold, cruise speed and maximum aerobic effort.
Anaerobic threshold training (sometimes called AT pace training) is the pace a swimmer would apply when doing the USMS One Hour Swim. Interestingly, swimming at speeds well in excess of this speed have been found to be less effective in creating maximal aerobic endurance capacities. This factor is of particular importance to some excessively goal-driven Masters swimmers and quite a few triathletes. Due to the rapid influx of lactic acid inhibiting the adaptation of aerobic metabolism, if you do much of your training faster than your AT, you could end up with inefficient and ineffectual training of both the aerobic and anaerobic energy systems.
Cruise speed training is a level of effort useful for days when you need rest. To be effective, it needs to be at a level just above your aerobic threshold, usually at about 70 to 75 percent of maximum. Efforts are moderate, and you should feel as if you can pick up the pace at any time. This type of training is invaluable for energy replacement, and it is essentially the "backing and filling" of your aerobic conditioning.
Maximum aerobic effort is necessary to push your aerobic conditioning to the highest levels. However, it is stressful to the system due to the large amount of lactic acid production associated with a significant amount of muscle glycogen depletion. Due to the demands of this type of training, it should account for no more than 20 percent of your aerobic distance training.
Here's how to make a quick determination of your aerobic energy system: Calculate 60 percent of your personal maximum heart rate, then do a maximum aerobic type main set. (To calculate your maximum heart rate, subtract your age from 210 if you're in good shape or from 220 if you're not yet in good shape.)
If your heart rate averages a drop from near maximum to below 60 percent in less than 30 seconds after each swim, your aerobic energy systems are probably maximized. In this case, it would be more productive to spend more time on race specific training. Use anaerobic threshold and maximum aerobic effort sets only to maintain your level of aerobic conditioning.
If your heart rate averages a drop from near maximum to the 60 percent level in 30 to 60 seconds after each swim, you need to work on improving your aerobic conditioning. Use AT pace training sets, such as 20 x 100 free with 10 seconds rest. Even, fast-paced swimming is a good way to test and monitor positive shifts in your anerobic threshold.
If your heart rate takes more than one minute to drop to the 60 percent level, you need to work on basic aerobic conditioning. In this scenario, it would be counterproductive to try to do maximum aerobic training sets. The bulk of all your training should be between cruise speed and AT pace mode, and high intensity anaerobic training should be minimal.
Anaerobic Training
When done properly, anaerobic training can yield big dividends because you are essentially training your body to deal with the discomfort of increased levels of lactic acid and the resultant drop in muscle pH. You can train your body to increase the production of lactic acid. It is actually an energy source. Additionally, you can enhance your ability to re-synthesize lactates and buffer lactates (just as Tums works on stomach acid).
If you can train your body to produce lactic acid faster, in larger quantities, while also buffering and clearing it out of the working muscles more efficiently, you should be able to sprint longer and faster at the end of your race. Moderation is the key. Do not attempt to do all forms of anaerobic training on a daily basis. Not only will it become counterproductive, but it could be dangerous, especially if you have not built up a solid aerobic foundation.
There are two types of anaerobic training: anaerobic endurance training and anaerobic power training.
The emphasis of anaerobic endurance training is facilitating the production of lactic acid by swimming fast repeats with short rest, approaching the maximum heart rate. Broken swims are one variation of this form of training. This type of set not only helps enhance your lactate tolerance, but it helps fine-tune your pacing skills. Anaerobic power training increases the ability to buffer and re-synthesize lactic acid. Swim short, fast repeats followed by short recovery swims (see Chart #2).
Speed Training
Speed training is meant to help you improve your ability to start races faster and more efficiently. For full effect, swim short repeats at race pace or faster with a generous amount of recovery time. The recovery period should be long enough to avoid accumulation of lactic acid. Insufficient recovery time will defeat the purpose. You should only feel mild lactic acid-induced discomfort. Speed training is enhanced by resistance and speed assisted swimming (see Chart #3).
Be sure to do your primary strokes to facilitate maximal adaptations in the specific muscle fibers. To enhance your speed training, try doing explosive starts off the blocks with half- or full-length sprints on long rest. Armed with this information, you should be able to practice converting your single-speed body into a finely-tuned, six-speed racing machine.
Train to train, or train to race -- the choice is yours!
Chart #1: Aerobic Training
Subtype of aerobic work Repeat Distances Rest Intervals Set Duration % of Aerobic Work % of Max. HR
Anaerobic Threshold 300 to 500 yd/m 10 to 30 sec. 20 to 30 min. 50% 70-85%
Cruise Speed 100 to 300 yd/m 5 to 20 sec. 15 to 30 min. 30% 60-70%
Max. Aerobic (VO2 max) 200 to 400 yd/m 1 min.to 2 min.+ 12 to 15 min. 20% 85-92%
Chart #2: Anaerobic Training
Subtype of aerobic work Repeat Distances Rest Intervals Set Duration % of Anaerobic Work % of Max. HR
Anaerobic Endurance 50 to 200 yd/m 30 sec. to 2 min. 600 to 800 yd/m 75% 92-97%
Anaerobic Power 50 to 100 yd/m 3 min.+ 200 to 400 yd/m 25% 97-100%
Chart #3: Speed Training
Subtype of aerobic work Repeat Distances Rest Intervals Set Duration % of Aerobic Work % of Max. HR
Speed assist (w/fins) 5 to 25 yd/m 1 to 5 min. 100 to 300 yd/m 50% Not applicable
Speed resist (w/tubing) 5 to 25 yd/m 1 to 5 min. 100 to 300 yd/m 50% Not applicable
Doug Huestis, M.S., coaches the Fog City Masters in San Francisco. He is a member of the USMS Sports Medicine Committee and is Administrative Vice Chair of Pacific Masters Swimming. He holds a master's degree in exercise physiology, and is formerly the head Masters coach for The Olympic Club (1990-97), where his swimmers broke over 200 Masters national and world records.