Concept2 Forum

From PubMed:

Scand J Med Sci Sports. 2009 Feb 2. [Epub ahead of print]

Scaling concept II rowing ergometer performance for differences in body mass to better reflect rowing in water.

Nevill AM, Beech C, Holder RL, Wyon M.
School of Sport, Performing Arts and Leisure, University of Wolverhampton, Walsall, West Midlands, UK.

We investigated whether the concept II indoor rowing ergometer accurately reflects rowing on water. Forty-nine junior elite male rowers from a Great Britain training camp completed a 2000 m concept II model C indoor rowing ergometer test and a water-based 2000 m single-scull rowing test. Rowing speed in water (3.66 m/s) was significantly slower than laboratory-based rowing performance (4.96 m/s). The relationship between the two rowing performances was found to be R(2)=28.9% (r=0.538). We identified that body mass (m) made a positive contribution to concept II rowing ergometer performance (r=0.68, P<0.001) but only a small, non-significant contribution to single-scull water rowing performance (r=0.039, P=0.79). The contribution that m made to single-scull rowing in addition to ergometer rowing speed (using allometric modeling) was found to be negative (P<0.001), confirming that m has a significant drag effect on water rowing speed. The optimal allometric model to predict single-scull rowing speed was the ratio (ergometer speed xm(-0.23))(1.87) that increased R(2) from 28.2% to 59.2%. Simply by dividing the concept II rowing ergometer speed by body mass (m(0.23)), the resulting "power-to-weight" ratio (ergometer speed xm(-0.23)) improves the ability of the concept II rowing performance to reflect rowing on water.

Interesting! Could you just put the conclusion in simpler terms? Did I understand correctly in that you divide the pace in minutes by the mass times 0.23?

There's something not quite right about that. 4.96/3.66 = 1.36.

Lightweight men 50 years and older often win a national OTW 1k race in ~4:00.

That implies a sub-3:00 1K on the erg, which no masters lightweight approaches.

The use of the phrase "junior elite" tells you all you need to know about this study.

The only formulation I can make come close is OTW = 1.87 x OTE / (kg^0.23), but that would require the junior elite rowers to average ~56.7 kilograms, about 125 lbs.

At 70 kg, right now I'd have to hustle to break 9:00 for 2K OTE, for which the formula predicts 12:48 OTW, which is just about right.
(My last 1K OTW was ~6:04.)

The ratio 3.66/4.96, however, predicts 12:12 OTW, which would require much improved OTW technique. But that, I assume, the junior elites have.

A concept 2 rowing ergometer will never be able to accurately measure performance to reflect that on the water. All it does is measure work done through the flywheel. That combined with spm simply isn't enough to realistically tell you how you'd go in a boat. All the other factors that tell you how well you'd move a boat are abscent.

It can't measure balance,catches, finishes, ability to row long strokes with the oar in the water and how straight the drive through the water is. It won't tell you if you miss water by dipping your hands or lunging with your oar at the catch. Rowing your finishes into your gut or if you pull the oar right through to the finish or just dump the finish and cut the stroke short. It won't tell you anything about correct body position or body sequence. It ceratinly won't tell your ability to read boat run and not check the boat by taking the catch too early or release the oar too early. Nor will it tell your ability to handle wind, rain, current, wash and waves.

Furthermore, in the boat you use extra muscles for oar control and balancing the boat that never come into play on the C2 erg. Ask anyone, how fatigued they get, who has just got into a boat in spring after a long winter out of the boat on the erg.

Hence, it's a nonsense excercise to use any sort of formulae to try and work it out. If you must use an erg that gives at least some of the data necessary then you might as well use a Rowperfect erg. A Rowperfect"Indoor Sculler" allows you to select the boat speed (8+, 4-, 1x etc) , select single scull, enter in your weight and automatically displays the result on your monitor as you row. No need to work it all out. Plus with it's limited tilt seat, dynamic action and oar flex spring loaded handle the degree of difficulty is closer to that of rowing on the water. But it's still missing some of the vital criteria that I mentioned above. But to think that a C2 erg can do it is just laughable.

The watery average speed was 3.66 m/s, which means an average 2k time of 9.1 minutes. So they were taking the "researchers" for a ride: their erg 2k average was 4.96 m/s so 6.7 minutes. Or maybe they'd never been afloat before. Even I could do a 9 minute 2k in a 1x, albeit ten years ago when 63.