Erg Technique vs. Water Technique

After I linked to the Rowing Biomechanics Newsletter a few posts ago, I looked back at some past issues and found one that sheds a little more light on the erg discussion we've been having. At the risk of getting off topic (this isn't lightweight specific) or too technical, I thought I'd mention it.

This issue discusses handle and force measurements taken from a rower while rowing an erg and while rowing a single. On an erg, foot-stretcher force develops sooner than in a boat, but leg velocity is higher in a boat. This higher leg velocity means a higher percentage of power comes from the legs in a boat when compared to the erg. On the erg then, more power comes from the arms than in a boat. There is, however, greater acceleration of the arms on the drive on the water. If you look at the power breakdown among legs, trunk, and arms, it looks like this:

Erg - 37%,41%,22%
Boat - 45%,37%,18%

Quite often you see some rowers with good erg scores, and many land only rowers, whip the handle in a way you know wouldn't work on the water. Maybe this is why. There is no claim here that the tested rower has perfect form, only that given the same rower, one rows differently in a boat than on an erg. The Newsletter's author, Valery Kleshnev, concludes that,

a comparison of various rowers’ profiles show that the power production differs between ergo and on-water. Rowers with fast legs produce more power on-water, while athletes with slower legs and stronger upper body have relatively higher ergo scores.

This may be stating the obvious, but even before accounting for technique and chemistry, rowing an erg isn't quite the same as rowing a boat.