Swim Training for the 50 Freestyle

High Octane Freestyle Part III: Training 

The 50-meter sprint primarily involves two of the three energy systems we have available to use. Stored energy and anaerobic energy production are the two principal ways in which we delivery ATP to our muscles for this short, all-out burst of speed. However, at the very end of the 50-meter race, when most are either won or lost, the aerobic energy system begins to kick in. Therefore, aerobic swim training also plays a role in the 50-meter races.

All three energy systems have the capacity to change or adapt to the environment when they are stressed in that environment over time. That simply means to improve the anaerobic systems, one must train with a method that stresses those systems. The same goes for the aerobic system.

The stored energy supply (ATP and creatine phosphate) with maximal exertion will last about 8-10 seconds. I am not certain how much more available storage of this source of energy can be developed by stressing that system (alactic training), or by ingesting creatine, which is controversial, but it can change. Alactic swim training is done by repeated burst maximal efforts of 8-10 seconds so as not to require anaerobic production of ATP, followed by enough recovery time to restore the stored energy supply. That time is typically around 30 seconds or so.

Developing the other anaerobic energy system, the production of ATP anaerobically (anaerobic glycolysis), which predominates the energy supply between 10 seconds up to around a minute of maximal effort, comes from what is called lactate training. This type of training includes repeated maximal effort sets of longer than 10 seconds up to one minute or so with enough recovery time so as not to overwork the aerobic system. That rest period is typically 1 to 3 minutes or more, depending on the duration of the maximal effort. This part of the anaerobic system is not improved by increasing the production rate of ATP, which is the same in trained or untrained muscles, but rather by improving the ability to buffer lactate. The release of a free hydrogen ion as a byproduct of anaerobic glycolysis results in the lowering of the pH of the body. Lactate training improves the ability of the muscle cell to remove the free hydrogen ion. The human body has a very low tolerance for changes in pH (acidification or alkalization) and if the body becomes too acidic, muscle contraction begins to diminish significantly. Athletes know this feeling all too well as the proverbial piano on the back.

The quickest and easiest way for the human to increase the pH and restore it to more neutrality is by increasing the respiratory rate, blowing off more carbon dioxide, or so-called oxygen debt. That is why swimmers do not feel the need to breathe much at the beginning of the race, but as the race progresses and the pH lowers, the swimmer cannot get enough oxygen (or blow off enough CO2).

Since the aerobic energy system (aerobic respiration or oxidative phosphorylation) comes into play at the end of the 50 meters, sprinters must also develop this system to some degree. Too much of the training required to develop this system is detrimental to the sprinter, since it often results in a degradation of good sprint technique and can shift the composition of the muscles toward an increase in slow twitch fibers used in the endurance events. Typically, sprinters will devote the earliest part of the season to developing a stronger aerobic system and the middle and end of the season toward building the anaerobic systems.

While all three of these energy systems can be improved, depending on the type of training we do, the fact is that the muscle mass and composition have a lot to do with the success or lack of success of a sprinter. The predominance of fast twitch fibers results in the ability to generate much more power than with slow twitch fibers. These types of fibers do not recover as quickly as the slow twitch variety, so sprinters cannot sustain a high speed for very long. All swimmers also have a certain number of muscle fibers that sit on the fence. They can be converted to faster twitch, resulting in more power, or slower twitch, resulting in a faster recovery rate, depending on which way the swimmer trains. Anaerobic training shifts them toward the fast side, while aerobic training shifts them toward the slow side.

Swimming is unique in that it presents a paradoxical relationship between muscle mass and speed. Because of the extraordinarily sensitive relationship between a swimmer’s morphology (build) and frontal drag, bigger does not always mean faster. In fact, in races beyond 50 meters, bigger, even if it also means stronger, often results in slower performances. Strength training in swimming remains one of the most challenging and controversial subjects because of this unique paradox.

Finally, because of the significant contribution of the kick to a swimmer’s speed, there are exceptional sprinters that do not necessarily have the expected fast twitch muscle composition, yet manage to go very fast. My son, Gary Jr, was a good example of a swimmer that did not have a great vertical leap, but still managed to win a couple of Olympic gold medals in the 50 meter freestyle. His kicking speed was incredibly fast.

In conclusion, if it is your goal to become a better sprinter, no matter what anatomical or physiological cards you were dealt, first, learn to use a sprinter’s high-octane technique. Second, train to develop the anaerobic systems, but do not completely neglect the aerobic system. You need all three. Third, build swim-specific strength outside of the pool, but don’t get too bulky. Fourth, work on developing a faster kick, where you likely have the most to gain.

If you need help in any of these areas, come visit us at The Race Club. We’d love to help you train smarter and swim faster.

Yours in swimming,

Gary Sr.

Read High Octane Freestyle Part I of III

Read High Octane Freestyle Part II of III

14 Responses to Swim Training for the 50 Freestyle

  1. Keith Rennolls

    Excellent article presenting details of a sprinter’s traing needs, that are found almost nowhere else.
    Almost all the training schedules of swimming clubs in the UK expect all swimmers, including sprinters to do the endurance training done by the 400m swimmer… Two two-hour pool sessions per day with high milage.
    It seems the ASA coach training is all endurance orientated… The reason that historically the UK has produced very few world class sprinters.
    If a parent has a natural sprinter, they need to avoid the big clubs, and find a smakl club with a flexible coach.

  2. OluKayode Garuba

    I totally agree with you. It is really difficult to find the right balance

  3. William Spence

    High Octane Freestyle Part III: Training
    Very good explanation of what goes on during high level exertion. A point I try to make with track sprinters is that the Russian track sprinters always ran 10K at least once a week to build their aerobic base and while they may have not been the most gifted of natural sprinters, they always had good results.

  4. Chris Harrigan

    I thought the creative phosphate system range is roughly from 10-30 seconds?

    • garyhallsr

      Stored high energy phosphate (Creatine phosphate and ATP) lasts around 8-10 seconds with maximum effort. The anaerobic production of ATP then takes over until the aerobic production kicks in at around 20-30 seconds. The amount of production of ATP coming from each system (aerobic or anaerobic) after 30 seconds depends on the intensity and the duration of the exercise.

  5. Sam Carroll

    Can you explain ways a swimmer can trick the body in regards to CO2. While watching a swim video, the presenter talked about slowly letting out oxygen so that you trick the body’s response. That is, you want to keep some oxygen rather than exhaling out in one breath. Apparently, if you hold the breath or get rid of all the Oxygen, CO2 builds up and the body screams for Oxygen, making you panic. Sorry, I can’t describe better. I’m looking for ways to trick the body so it’s not screaming for oxygen. I’m thinking at turns…where you’re applying force, turning, and staying underwater for at least 5 strokes while not breathing. Drills for that? Also, I see some swimmers exhaling through the nose while underwater. Is exhaling through the nose intuitive or can it be learned or genetic? Any drills for that? Including dryland. Thank you kindly.

    • garyhallsr

      The build up of CO2 from not exhaling triggers a reflex to breathe.. a survival mechanism. Trickling some of the CO2 out from the nose under the bodies of great swimmers may have more to do with reducing frontal drag from the bubbles than altering the breath reflex…but you may be right.
      Training hypoxically as you suggest on turns helps the body to better buffer lactate or the free Hydrogen ion that lowers pH

  6. David Clevenger

    I have a 12 year old daughter that trains year round swimming both long and short course. Genetics have blessed her with power and speed but we are still fighting flexibility to get the proper rotation so she can fully use said power and speed. Is this something she should be focusing on now or do we wait until she has physically matured?

    • garyhallsr

      Getting more flexibility in key joints for swimming (shoulder, ankle, hip etc) should start early in the career..not late. We have a Race Club stretch routine that we recommend that works on all of the key areas, including core strength.

  7. Christine Luo

    Excellent article! Gary, the question I have is what a typical set looks like to train anaerobic system? I often heard the critical swim speed training for increasing the lactate threshold. Will that be considered as aerobics training or anaerobic training? Thanks!

  8. garyhallsr

    Anaerobic training consists of both lactate training (usually around a minute or less of maximal exertion (race pace) with long rest..example 6 x 100 fast from a dive on 5 mins) and alactic training (short 8-10 second bursts of maximum effort). The former helps the body to improve its ability to buffer lactate (keep a more neutral pH) and the latter helps increase the stores of high energy phosphate in the muscle (creatine phosphate and adenosine triphosphate).
    I know it is confusing, but the anaerobic (lactate) threshold is usually referred to during aerobic training when the demands for ATP exceed what can be supplied by the aerobic system alone. At that point, the anaerobic system kicks in and begins to produce lactate as a byproduct.

  9. Christine Luo

    Gary, thank you so much for the explanation! Now I have a clear idea of the differences between the three energy systems and explains why I see a big improvement in her aerobic but not in her anaerobic in events.

  10. Sharon

    Hi Gary,

    I am wondering your opinion on optimal training for 13 – 16 year old female 50 and 100 sprinters ?

    E.g. if doing 7 sessions per week with dry land, should they do predominately anaerobic training, or mainly short speed work etc ?

    Your articles are so helpful. Thankyou.

    • garyhallsr


      Mike Bottom (head coach of U of Michigan and former head coach of The Race Club) would train his sprinters in 3 cycles, with more aerobic training early in the season, lactate and power training in the middle, and speed/recovery training at the end. This process seems to work the best, as even a 50 sprint uses about 5% of the aerobic energy system…and it all comes at the end. Training in all five disciplines is also necessary; swim, strength, mental, nutrition and recovery.


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