Skip to content Skip to footer

Training the Energy Systems

In the last issue of The Catch, we looked at the human energy systems and how they work. Whether you’re a recreational SUP paddler, use SUP to train for fitness, or are a die-hard SUP racer, it’s worth understanding how the energy to drive our paddling muscles is derived from the food we eat.  But while it’s nice to know how our bodies produce energy to drive muscle contraction, it’s more important to understand how we can use this knowledge to improve energy production and, ultimately, our paddling performance.  So, let’s take a look at training the energy systems – the type of training we need to do, the adaptations that occur, and how they result in improved performance.  

What happens when we train

When we train, we’re creating a stimulus that challenges our body and causes it to adapt so that, over time, the challenges can be more easily met.  This principle of a training stimulus causing adaptations holds across all different types of training.  The adaptations, the body systems involved, and the specifics of how they occur may be different but ultimately it comes down to the body adapting in ways that make the task you’re performing easier.

If we consider technique, our nervous system, which controls both how we move (the muscles involved and the sequence in which they contract) and the amount of muscle fibers involved (the strength of the contractions) adapts over time to the stimulus training provides it so that our movement becomes more automatic, more efficient and more powerful.  

If we consider strength, our muscles respond to training stimuli in multiple ways.  For example, if the training stimulus is appropriate, we’ll increase the cross-sectional area of the muscle fibers and increase muscle size.  Or, if a different training stimulus is applied our muscles adapt through increased neural recruitment of muscle fibers, allowing us to bring more of the muscle we have available to bear in a given task.  

It’s no different if we consider our body’s ability to produce the energy required to drive muscle contraction.  Through training, we provide a stimulus and adaptations occur as a result of that stimulus which lead to an improved ability to produce that energy.  This can directly lead to improved performance.

ATP – a quick review

If you haven’t read “Understanding the Energy Systems” in last month’s issue of The Catch, now would be a good time to do so.  You can link to it here.

You’ll recall (and this is a real quick review) that a molecule called ATP is the body’s energy currency, providing the energy required to make our muscles contract.  You’ll also recall that this ATP can be produced through three different pathways (or energy systems) which, in varying ways, are fueled by the food we eat.  Either in the presence of oxygen (aerobic metabolism) or in the absence of it (anaerobic metabolism) this food energy is used to produce ATP which in turn releases large amounts of energy when broken apart in our muscle fibers.  It is this energy that drives muscle contraction.

So when it comes to training the energy systems the question is, what types of training stimuli are required and what adaptations result that can improve our ability to produce ATP?  Let’s start with the aerobic system first. 

Adaptations to aerobic training

ATP produced aerobically requires the presence oxygen, so at a systemic level we’re looking at training activities that stimulate adaptations that improve delivery of oxygen to our working muscles.  However, adaptations don’t end there.  Adaptations also occur at the level of the individual muscle fibers which result in an increased ability to produce ATP. 

Let’s take a look at some of the adaptations first, then the types of training that stimulate them.  At the level of our cardiorespiratory system the following adaptations to aerobic training occur:

  • Increased stroke volume:  Stroke volume is defined as the amount of blood leaving the heart with each cardiac cycle.  Blood leaving the left ventricle is oxygenated, meaning it is carrying oxygen to areas of the body that need it, including working muscles.  If stroke volume increases, more oxygen carrying blood is pumped from the heart with each beat.  
  • Increased cardiac output:  Cardiac output is defined as the amount of blood pumped from each ventricle in one minute.  For reference, normal cardiac output is about 5 liters/min in a normal, healthy individual.  It is much higher in a trained athlete that’s exercising.  The more blood leaving the left ventricle in one minute, the more oxygen is being delivered.
  • Decreased resting HR, increased max HR:  Resting HR decreases as an adaptation to training as an increased stroke volume results in the same amount of blood being pumped to meet the body’s basal needs.  Highly trained athletes have a marginally higher max HR, which along with increased stroke volume result in greater cardiac output.  
  • Increased oxygen uptake:  This is the ability to take in oxygen through the respiratory system, get it to the working tissues via the cardiovascular system, and use it to produce energy.  Maximal oxygen uptake or VO2max is the oxygen uptake attained during maximal exercise that cannot be increased further despite further increases in exercise workload. VO2max is greater in trained athletes as a result of adaptations stimulated by their training.
  • Increased haemoglobin levels in blood:  Haemoglobin is the protein in red blood cells that carries oxygen.  Higher haemoglobin levels increase the oxygen carrying capacity of the blood.  Haemoglobin levels increase as an adaptation to aerobic training.
  • Increased anaerobic threshold:  Anaerobic threshold is the point at which the demand working muscles have for oxygen can no longer be met, meaning production of ATP aerobically has maxed out.  Any additional ATP required must then be produced anaerobically.

Basically, these adaptations contribute to improved aerobic performance by increasing the amount of oxygen that can be delivered to working muscles, allowing more ATP to be produced aerobically.  This, of course, should be of interest to SUP racers.  However, it should be noted that these adaptations also provide huge health benefits by increasing cardiac health and the ability to transport oxygen to tissues other than working muscles.  This should be of great interest to everyone that paddles. 

Beyond adaptations at the level of the cardiorespiratory system, there are adaptations to aerobic training that occur at the level of individual muscle fibers as well:

  • Increased myoglobin:  Myoglobin is the protein within muscle fibers that carries oxygen from the cell membrane to the mitochondria.  Myoglobin increases in skeletal muscle as an adaptation to aerobic training and means that more oxygen can be moved within muscle fibers of trained individuals, increasing its availability for use in aerobic metabolism
  • Increased number of mitochondria:  The mitochondria is the “powerhouse” of the cell and the site at which ATP is produced through aerobic metabolism in the muscle fiber.  The greater the number of mitochondria, the more ATP can be produced.  
  • Increased activity of aerobic enzymes:  Enzymes essential in aerobic metabolism increase as an adaptation to aerobic training

So, now that we know the types of adaptations that occur in response to aerobic training, let’s take a closer look at the type of training that’s required to stimulate them.

Training aerobically

Aerobic training can be grouped into two different types of training, largely dictated by intensity.  Base level aerobic training is generally lower in intensity and must be done for longer periods.  Work done at level 2 to 3 (60 to 75% of max HR) for prolonged periods forms the basis of most aerobic training programs.  In fact, adaptations at the level of the muscle fibers are not intensity dependent but rather time dependent.  How long you train for matters more than the intensity you train at when it comes to these adaptations.  Thirty minutes of sustained level 2 to 3 aerobic activity is great, but longer is better.  Sixty minutes is better than 50 and 90 minutes is better than 60.  

Higher level aerobic abilities like anaerobic threshold and aerobic power (VO2 max) need to be trained at higher intensities.  When training these higher-level components of aerobic fitness, it is not unusual to be training right at the capacity of the body’s ability to meet the oxygen demands of the working muscles, or even exceeding it.  So, when training aerobic power, for example, there is usually some degree of anaerobic component to the work as well.  

Training aerobic base

Training can get awfully boring if all you are doing is 60 to 90 minutes (or longer) of steady state aerobic work at level 2 to 3.  Fortunately, interval training can meet the same objectives.  The key when doing intervals to train aerobic base is that the work to rest ratio should be high – 5:1 or greater – and an adequate number of reps and sets must be performed so that a sufficient total training time is achieved.  Again, the effectiveness of base training is time dependent.  It is more important to spend more time in a comparatively lower training zone than it is to spend less time in a higher zone.  

Here are some sample workouts for training aerobic base in SUP which offer 30 to 90 minutes of work, depending on which end of the provided range you’re working at:

  • 30 to 90 min steady level 2
  • 30 to 90 min steady level 3
  • 30 to 90 min continuous fartlek level 2 to 3 (fartlek is a Swedish term meaning “speedplay” or changing tempo)
  • 20, 5, 10, 5 min, 30 sec to 1 min rest.  20, 10 min at level 2, 5 min at level 3
  • 5, 10, 5, 20, 5, 10, 5 min, 30 sec to 1 min rest.  20, 10 min at level 2, 5 min at level 3
  • 3 to 9 x 10 min, 30 sec to 1 min rest.  Can be at level 2, level 3 or split between level 2 and 3
  • 6 to 18 x 5 min, 30 sec to 1 min rest.  Level 2, 3 or mixture
  • 1 x 10 min, 2-3 x 5 min, 1 x 10 min, 2-3 x 5 min, 1 x 10 min.  10 min at level 2, 5 min at level 3.  No rest after 10 min, 1 min rest after each 5 min
  • 10, 8, 6, 4, 2, 3, 5, 7, 9, 11 min, 30 sec to 1 min rest, 7 min and above a level 2, below 7 min at level 3.

Note the large work to rest ratio in each of the above workouts.  These sample workouts just scratch the surface of what you can do with a little imagination by following the format of high work to rest and sticking with the level 2 to 3 range of work.  

You may be wondering when you should paddle at level 2 and when you should paddle at level 3.  In all honesty, I don’t think it matters that much.  I try to do at least half of the work in any given training week at level 2.  Remember, adaptations to low level aerobic training depend more on the duration of the exercise than the intensity.  If you can go longer at level 2 then at level 3, then training at level 2 is preferable.  That said, there are both technical and pacing considerations when paddle training, especially if you are training to race.  It is important to regularly paddle a little harder in your aerobic base training to become competent at pulling a little harder and faster from a technical perspective.  You don’t learn to paddle faster with good technique if you’re always paddling slower.  It is also easier to learn a sense of more race-relevant pacing if the intensity is a little higher than level 2.  

Both level 2 and level 3 training zones offer a pretty wide range of effort for most paddlers.  For example, a low level, level 3 effort is pretty much a hard level 2.  A low level, level 2 effort is almost too easy.  A high level, level 3 effort is considerably harder and approaching level 4.  Obviously, the lines blur between these levels a little.  I’ve never been too concerned about staying in level 2 and avoiding level 3 work like some coaches who, in my opinion, are perhaps a little too rigid with their training zones.  Paddling at level 3 offers a bit more realism to your training in terms of technique and pacing, particularly if you are a racer.  The key is to make sure that you aren’t always training base at the high end of level 3.  Again, in my experience a good rule of thumb is that at least 50% of your work should be level 2.  

Training higher-level aerobic abilities

While aerobic base training provides some stimulus towards foundational development of increased anaerobic threshold and aerobic power (VO2 max), if you’re really interested in improvement in these areas you need to train at higher intensities.  Realistically, this work needs to be done at a high-end level 3 or level 4.  While the work to rest ratio is still greater than 2:1, the training intervals are generally shorter than in base work and the rest periods longer.  

Training to elevate anaerobic threshold involves dancing along the boundary between aerobic and anaerobic effort as you do your work.  Again, time in training zone is important but now so is intensity.  Spending considerable amounts of time at threshold or shorter periods above it will help to push your aerobic capacity higher, building on adaptations made in the base work and increasing your body’s capacity to deliver and utilize large amounts of oxygen in muscles.  Improvements in these areas allow you to go both harder and longer aerobically, before you reach a point where ATP produced aerobically needs to be augmented with ATP produced anaerobically in order to maintain your work rate.  

Training aerobic power to increase VO2 max involves pushing to high sub-maximal to near maximal levels.  While this level may be hard to sustain for extended periods, doing work in intervals allows you to increase the total time spent in a workout at this level, thus maximizing the training effect.  While intensity is quite high and the intervals shorter, the work to rest ratio is still 2:1 or greater.  

Obviously, working at this intensity is going to see production of lactate as a result of a greater amount of the work being done anaerobically than when training aerobic base.  This blurring of the boundary between aerobic and anaerobic work in high intensity training reflects how both systems work in parallel and at the same time in competitive athletic situations.  

Here are some sample workouts for development of anaerobic threshold and aerobic power:

Anaerobic threshold

  • 2 to 4 sets of 10 x 70 sec level 4, 20 sec rest, 3 min rest between sets
  • 30 to 50 min of 40 sec level 4, 20 sec rest
  • 1 to 2 x 5 km time control (covering the distance as fast as you can), 8 min rest
  • 2 to 4 x 2 km controls, 8 min rest

Aerobic power

  • 6 to 10 x 4 min, level 4, 2 min rest
  • 1 to 2 x 4 min, 2 to 3 x 3 min, 2 to 4 x 2 min, level 4 or higher, 2 min rest

Again, there are countless ways to change the numbers in the intervals and accomplish the desired training effect.  A little imagination and a willingness to experiment is all you need.

Adaptations to anaerobic training

Similar to the adaptations seen in response to aerobic training, our bodies experience adaptations to anaerobic training as well, such as:

  • Increased number of mitochondria: This is an adaptation to aerobic training as well, and occurs largely because, in order to work anaerobically, you first have to max out what your aerobic system is capable of.  
  • Increased capillarization:  Capillaries are the smallest blood vessels which supply the target tissues, in this case the working muscles.  Since anaerobic training by definition layers on top of a maxed out aerobic system, both aerobic and anaerobic training contribute to the increase in capillarization.  Increased capillarization results in better blood supply to muscles, meaning enhanced oxygen and nutrient delivery and removal of waste products such as lactic acid. 
  • Increased buffering capacity:  Production of lactic acid as a by-product of anaerobic metabolism elevates blood acidity, eventually leading to muscle failure.  One prominent adaptation to anaerobic training is an increased capacity to buffer blood pH, reducing the effect of lactate on continued performance.  
  • Increased activity of anaerobic enzymes:  Enzymes essential to anaerobic metabolism increase as an adaptation to anaerobic training.

These adaptations either contribute to improved aerobic performance, thus delaying the need for the onset of anaerobic production of ATP, or to improved anaerobic performance and increased tolerance to high levels of lactic acid.  

Training Anaerobically

Unlike aerobic training, anaerobic training is done at higher intensities of shorter duration with longer periods of rest.  Consider anaerobic work to be done at level 4 or above.  Work to rest ratios range from equal up to 1:10, depending on the focus on the work being done.  

Lower intensity (level 4) anaerobic work is generally aimed at developing speed endurance and lactate tolerance.  Higher intensity anaerobic work lasting in the 45 to 90 seconds range is aimed at both production and then tolerance of lactic acid.  The shortest anaerobic workouts in the 10 to 15 second range are targeted at the ATP-CP system and see the greatest amount of rest, enough for creatine phosphate to be replenished during rest intervals.  

Because anaerobic work is done at such high intensity, it requires much greater recruitment by the nervous system of available muscle fibers in the paddling muscles.  This means that more muscle fibers are engaged in anaerobic work and that the demands on the nervous system are greater.  This increased neural involvement is another reason why more rest is required than in aerobic training.  

Here are some sample anaerobic workouts:

Speed endurance and lactate tolerance

  • 4 to 6 sets of 10 x 30 sec level 4 or higher, 30 sec rest, 3 min rest between sets.

Lactate production and tolerance

  • 6 to 10 x 45 to 90 seconds, all out, 4 to 6 min rest

Neuromuscular speed and lactate production

  • 8 to 10 x 20 to 30 seconds, all out, 6 to 8 min rest

Neuromuscular speed anaerobic alactic training

  • 8 to 10 x 10 to 15 seconds, all out, 8 to 10 min rest

Again, with some imagination you can come up with a number of different intervals for each type of anaerobic training, though because of the short length of the work pieces, the possibilities are more limited than they are for aerobic training.  

What to train and when

Clearly there are considerable differences between aerobic and anaerobic training.  For that matter, there are considerable differences between the different types of aerobic or anaerobic training as well.  You can’t train everything at once and it is best to have a plan with regards to when you are going to introduce a certain type of training into your program, what you are going to remove from your program to make room for it, and how often and for how long you are going to do that training.  These are all considerations that need to be taken into account when setting the periodization of a training program.  Since setting up a periodized program is beyond the scope of this post, let’s instead take a look at a few tips for including all these types of training into your program.

  1. Start with aerobic base first.  SUP is primarily an aerobic sport.  Most of the races are distance races.  If you’re going to perform well you need a good aerobic foundation.  For those that aren’t racing and are using SUP for fitness, the main cardiovascular health benefits that you look for from training are pretty much the adaptations derived from aerobic base work.  I’d suggest a training block focused exclusively on aerobic base for 8 to 12 weeks, especially at the start of each paddling season.
  1. Mix in higher level aerobic work.  After you’ve completed a block of aerobic base training, add in some higher-level aerobic work.  I’d suggest 2 to 3 workouts a week, well spread out from each other.  The rest of the week and at least 50% of the training should still be dedicated to aerobic base work.
  1. Include anaerobic work as needed.  If you’re racing, you’ll have a need for well-developed anaerobic abilities.  If you’re just training for fitness, anaerobic workouts can still be fun and valuable.  These are analogous to the High Intensity Interval Training (HIIT) workouts you see discussed in fitness publications and, since they require the aerobic system be maxed out before anaerobic work really starts, can create some of the same adaptations as higher-level aerobic training as well.  Add these into your program after you’ve done 6 weeks or so of higher-level aerobic work, replacing it with the new anaerobic work you add.  Again, you don’t want to do more than 2 to 3 anaerobic sessions/week which are well spread out.  The rest of the work in your week should always be, at the very minimum, 50% aerobic base.  Do your anaerobic training block for approximately 6 weeks at a time.  
  1. Sequence your anaerobic work.  Don’t just jump into anaerobic training with neuromuscular speed.  Start with some speed endurance work or longer anaerobic work for a few weeks before trying the shortest, most intense work.
  1. Don’t be afraid to go back to a base focus.  You can’t train at super intense levels indefinitely.  If you try you’ll undoubtedly see diminishing returns at first and then, perhaps, signs of overtraining.  This can be prevented by periodically returning to a training block focused on development of aerobic base.  Remember, periodically changing the training stimulus is the key to effective periodization.
  1. Cycle your work with periodic easier weeks.  We can’t go hard all the time.  Attempting to do so will only result in diminishing returns in your training and risk overtraining.  Do two to three harder weeks in which you progressively build the training load, then do an easier week, reducing training load by as much as 50%.  This will ensure that the quality of the work in the harder weeks is optimal and make it much more likely you’ll feel strong for the entire season, rather than tail off towards the end of the season, develop an injury or illness, or risk overtraining.   
    1. Rest is rest.  In any of the sample workouts provided above, when it says “rest” the expectation is that you actually rest.  Rest can mean stop and sit down on your board.  Or just stop and stand there.  Maybe after half of the rest interval has passed you can start to paddle very slowly again and start thinking about the next work interval.  Rest is NOT paddling at level 2 between the harder intervals.  Getting the best rest possible ensures that the next piece you do in your workout can be done with optimal quality, both in terms of effort and technique, and it is consistent quality that makes training successful.
  1. What you can do on the water, you can do on land.  Any and all of the workouts described here can be done on land as well as on the water.  In fact, many land-based activities are superior aerobic training activities as they use more muscle mass than we do paddling.  Activities that involve your legs more than paddling does require a greater total demand for oxygen because more muscle mass is being used.  These activities load your cardiovascular system more than paddling does, and can have a greater aerobic training effect.  

Here’s hoping you’ve found this two-part series of posts on the energy systems useful.  Understanding what’s going on in your body to produce energy required for muscle contraction is important, but knowing how to train the energy systems so your ability to produce that energy improves is even more so.  Whether you are new to paddling, training SUP for fitness or an active racer, having an idea of what you are trying to accomplish in your training and how to do it better makes your paddling both more fun and more productive.  

Happy Paddling! 

Paddle Events

May 26, 2024 06:00

California River Quest

Overview The California River Quest is a marathon/ultramarathon paddling race on the Sacramento River in Northern California. Racers may choose 25, 50, 75, or 100 mile courses. We welcome all…
The Dean Randazzo Cancer Foundation's 2024 Paddle for a Cause
June 8, 2024

18th Annual Paddle For A Cause

22.5 mile around Absecon Island [Atlantic City] , a separate 6 mile fun/race and a 1 mile team SUPsquatch race
June 23, 2024

DeSatnick Foundation Around the Cape Paddle

The 10th Annual Around the Cape Paddle will be held on SUNDAY JUNE 23, 2024 in Cape May NJ.

Recent Classifieds


Black Project Hydro S *80 sq in) blade


PRONE Paddleboard Hypr Hawaii 14′ Carbon


12ft 6in Darkroom Custom Racing Standup Paddleboard


one edge pro 2.0 hollow 14′ x 23.5”


2023 allstar wood carbon 14′ x 26”

Subscribe for Premium Content and Coaching

Join the Paddle Monster paid Plan Today!

Content and coaching for all levels. From paddle content, tips and community to full coaching, join Paddle Monster today!