Translating Calories to Split Times for CrossFit Rowing Workouts on the Concept2

I recently received a question on whether there is a translation formula to convert Calories, commonly prescribed in CrossFit WODs that involve rowing, into 500m split times or watts, more commonly used by rowers to gauge pace.  CrossFit workouts use Calories on the Concept2 performance monitor to approximate “reps” when combining rowing with barbell movements or other rep-centric movements.

There is a complex formula behind the Calories measurement, and it does not translate directly into meters or watts because it is a measure of energy burned for a theoretical 175-lb. individual instead of mechanical work (i.e. distance the chain travels).

As a rower, however, I have a sense of the “pace” I need to maintain in Calories for certain WODs to generate desired results.  For example, in Fight Gone Bad I know that I should target a 1500-Calorie pace for the 1-minute rowing intervals in order to finish at 25+ Calories for the interval.

I decided to experiment a little to see if I could generate approximate Calories-to-pace conversions for 500m pace times from 2:00 down to 1:25 in 5-second intervals.  I did this by setting up 100-meter fixed distance intervals with 1 minute rest at drag factor 125, putting the display on average 500m pace, and trying to end each interval at exactly the target pace I desired.  For example, for the 1:45 pace target interval, I rowed for 100m, varying my pressure to try to end at exactly 1:45.0 average pace.  Then I could switch the display to Calories to see what that translated to.  It is of course impossible to hit the target average splits exactly, but here’s what I came up with:

image

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As you can see, Calories increases faster with pace than watts – it is not a linear relationship.

I hope this helps as a guideline for those integrating rowing with CrossFit!

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9 thoughts on “Translating Calories to Split Times for CrossFit Rowing Workouts on the Concept2

    • Thanks Rose, I would say for regular training calories is not a great way to gauge your progress – I would use pace per 500m, which is what most rowers use. CrossFit uses Calories in WODs because it (very) roughly translates into “reps,” but for training on the rower the pace per 500m split time is a better gauge.

  1. I wouldn’t be so sure about the watt conversion. When I cycle at a level pace higher RPM generates higher wattage, so I’d be inclined to suggest the same would occur in rowing.

  2. Hi DC, I agree with you, but the issue is that the RPM in cycling is much higher than the strokes per minute in rowing. The rowing stroke generates much more power than the cycling “stroke”, but the recovery phase in rowing generates no power and accounts for a greater % of the stroke cycle than in cycling, so on average the watts are lower. So I would expect that watts on the rower would track with watts on the bike only in very short, high-rating, sprint pieces (maybe 1 minute or less). Anything longer, the watts on the rower will not track upward in a linear relationship to RPM, rather they will increase more slowly on the rower than on the bike. There are some good threads that discuss this phenomenon as many rowers also do cycling, although I am not one of them. Check out http://forum.slowtwitch.com/forum/Slowtwitch_Forums_C1/Triathlon_Forum_F1/Cycling_watts_vs._erg_watts_P4873772/
    Appreciate any further comments/thoughts on this, or any comparative data you may have from your own experience.

  3. From the data you show calories did not increase faster than watts – just the opposite. For example, going from 1:59.5 to 1:25.0 watts increased by a factor of 2.78 (569.9/205.1). Calories increased by a smaller factor of 2.25 (2261/1005). The curves are misleading to the eye because the value scales of watts and calories are (arbitrarily) different but are plotted using the same axis.

  4. Ken – fair criticism – this was far from a scientific study. I believe the actual formula used by the C2 is:
    • Calories/Hour = Kcal/hr = (watts) x (4) x (0.8604) + 300
    This formula assumes a person of 175 pounds (80 kg) and a base rate of 300 cal/hour to move your body through the rowing motion at 30 strokes/minute.
    I’ll try to redo the chart above at some point based on this calculation instead of “as observed” values.

  5. Good to have a conversion. I took third at CRASH-Bs a number of years ago in 50-59 age group – 6:25.5 for 2K. Agree that rowers use the 500 split time as that is what matters in a 2K erg race or a race on the water. There is also less variation on the 500 split time than in calories per hour. Also, the most efficient way to row 2K on the erg is almost exactly even splits through first 1700 to 1800 meters and then row all out last 2-300. That’s why memory function on erg is good to look at to see splits through the different 500s. You should shoot for less than a 1 second average split time through first 3 500s. Last 500 should be slightly faster. Middle 1000 in an erg race is toughest.

    • Mark – agree on your points. I encourage my non-rower CrossFit colleagues to shoot for consistent splits and preferably to think about target splits before they undertake a workout. Congrats on your CRASH-B performance! May I be able to even get close to that in a few years when I get into that age group.

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