Applied Power Training for Rowers, Part 1

Summary

  1. Switch your erg sessions to use power – it is more linear and easier to compare than splits.
  2. Do regular tests to track performance changes, discover what training gives you the best results
  3. Use the linked spreadsheet to calculate aerobic and anaerobic power
  4. Determine power (/split) training zones for intervals
  5. Row more!

Introduction

The goal of any training is to get faster. How do we get faster as rowers?  Technique and fitness.  I won’t pretend to address technique here, this is just about developing your fitness to the highest level possible.

So how do we get fitter?  How do we know when we are getting fitter?  And how do different exercises affect our fitness?  Hopefully this write up will help to explain a few of my ideas regarding this, which are adopted from cycling/triathlete training and sports physiology.

Why else do we want to get fitter?  To eat more cakes, of course.

Note: all of this can be applied in exactly the same way to other sports by simply changing the variable: for running and swimming use pace, for cycling use power etc.

Energy systems

There are 3 systems that contribute to producing power in the body: Aerobic, Anaerobic and Neuromuscular. Briefly:

Neuromuscular

  • ~10sec power
  • strength
  • creatine-based
  • weight training to improve
  • improves slowly but detrains slowly too

Anaerobic

  • ~3min sprints
  • glucose (without oxygen) based
  • lactate build up
  • interval training to improve
  • improves quickly (6 weeks to max) but detrains quickly too

Aerobic

  • potentially unlimited duration
  • long term power source
  • fat & glucose + oxygen based
  • long sessions to improve
  • improves slowly but detrains slowly too

Note that the total output power is the SUM of these systems – for example if you pace yourself, your anaerobic system can contribute power over the duration of the exercise, not just the first 3mins.

 

Threshold power

The concept of threshold power describes the idea that, for a fixed unit of time, there is a maximum average power output that one can sustain.  For example, you might be racing in a 1k race (~3-4min) and sustain a power output of 300W, after which you collapse from exhaustion.  In comparison, over a 2k race (~6-8min) you might only be able to sustain a power output of 200W after which you collapse.  If you continue this line of reasoning, there is presumably a power output at which you can sustain more or less indefinitely as long as you get a ready supply of chocolate bars and water!

So if we plot the maximum threshold powers against time, we get a graph that looks something like the following:


That looks quite a lot like a hyperbola, and it turns out that we can model it as one.  The 4 dots are my 500m, 1k, 2k, and 5k average power (= splits).  This model breaks down a bit in the region below 1-2mins as you obviously can’t produce infinite power, but greater than this, and out to an hour or so it is reasonably accurate.  See a further post for an extension to the model that includes this area.  If we instead plot energy (so the power*time against time sustained for) against time then we get a linear relationship:

It is of the form y = m*x + c.  If we go through the maths (a bit of handwaving) it turns out the parameters correspond to m = the slope = “critical power” (the asymptote of the power graph above – the power output you should be able to sustain infinitely; or your aerobic power) and c = the intercept = anaerobic work capacity (sometimes called maximum oxygen debt, or how much anaerobic power you can put in above your critical power level).

Before you go thinking that I am some sort of genius for coming up with this; actually it is based upon the the Critical Power Model developed by RH Morton.  There is further reading here

The big thing to take away from this is that your anaerobic power is a capacity limit when you’re exercising above your aerobic power; whereas your aerobic power is a power limit.  So we have a reserve “battery” that we can use for sprinting above a certain power output, but it only contains a limited amount of energy; if we sprint less hard we can go for longer but eventually have to drop below the aerobic power level.

This makes complete sense and matches what we feel when we go too hard and blow through all our anaerobic capacity in the first 1000m of a 2k.  If we take it easier, we have more capacity in reserve, and can lift at the end.

So from this graph, we can see the relationship between your anaerobic and aerobic energy systems.  This goes some way towards illustrating why rowers have to be heroically aerobically fit even though the races are only 6-8mins long; the races are still about 80% using your aerobic system.

Fun with maths/examples: from the above, my critical power/aerobic power = 264W, and my AWC = 27kJ.  So, using this I can predict pacing for different lengths of time.

Power(av) = CP + AWC/t

eg

3min:

=> 264W + 27k/180sec = 264W + 150W = 414W

=> 1:34 splits for 3mins

=>64% Aerobic

7min:

=> 264W + 27k/420sec = 264W + 64W = 328W

=> 1:42 splits for 7mins

=> 80% Aerobic

30min:

=> 264W + 27k/1800sec = 264W + 15W = 279W

=> 1:48 splits for 30mins

=> 95% Aerobic

Aside: Splits vs power

Ergometer splits on a Concept2 are mathematically equivalent to power through the following relationship (from concept2.co.uk):

Power (watts) = 2.8/(500m_split_seconds/500)^3

Power in watts is easier to work with and gives a more linear response – eg, 5W is always 5W between 100-105W and 300-305W, but 1 second is hugely different between 1:31 – 1:30 and 2:31 – 2:30 splits.  I prefer to use watts, but remember it can be converted to splits if desired.

Additionally, watts then gives us the capability to compare to other exercises, so your cross training on the bike at the gym can be meaningful against your rowing training.  Watts can also be normalised for different athletes by dividing by weight to get watts/kg for comparison too.

 

Relating this back to Energy Systems, Training, and Cakes

From the graphs above, we can see now the interplay of the Aerobic and Anaerobic energy systems.  We now have a way to measure the two major energy systems involved in rowing.

The way I like to think of it, is that your Anaerobic Capacity is the icing on the Aerobic cake.  Doing lots of hard, short intervals (and eating lots of carbs!) will up your Anaerobic Capacity – to a point.  Usually it takes about 6 weeks of hard interval training to max out your Anaerobic system, but it detrains just as quickly.  So this explains why it is a great idea to do plenty of hard intervals in the run up to a race.

However, the base of the cake is your Aerobic system.  This is much slower to develop than the Anaerobic, but the gains stay with us for longer too.  According to Arthur Lydiard, the distance running guru:

“Aerobic development is essentially unlimited; the only constraints are training opportunities (available time, environmental conditions), training capacity, motivation, and resistance to injury/illness.” – http://www.lydiardfoundation.org/pdfs/osakalecture.pdf

Hooray!  So for the remainder of the year, we want to be doing whatever it takes to increase our Aerobic power.

 

Things to note

Stroke rate and drag factor affects the output.  There is a particular stroke rate and drag factor that is optimal for your physiology and power output.   For example, your 6k R18 session will likely be a long way from your predicted power for that time.  This is because a rating of 18 is unlikely to be close to efficient for your body, ie, you can produce more power at a higher rating.  I believe you’re best to be training at whatever stroke rate allows you to develop the best power for the lowest effort.

 

Wow, that’s great Nick. But what does it actually mean for me?

There are several things that you can take away from this:

– Row more often, on the erg or on the water.  DO IT!
– You now have a way to fairly accurately judge your current fitness in terms of anaerobic and aerobic components
– You can track improvements in these different areas, and see what training that you do gives you the most ‘bang for buck’
– You now have a way to relate different piece splits (eg, how does your 500m time relates to your 5000m time)
– You now have a way to estimate pacing for races (ergs or otherwise)
– You know how hard to train for different interval lengths

 

See part 2 for a continuation of this.

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