High-Resistance Interval Training Improves 40-km Time-Trial Performance in Competitive Cyclists by Amy M. Taylor-MasonSportscience 9, 27-31, 2005 (sportsci.org/jour/05/amt-m.htm)
The author of the study substituted two days of "high resistance" intervals - akin to low stroke rate work in rowers during the cyclists competitive phase of training - a time most cyclists (crews?) are focussing on lower reistance high cadence work closer to race intensity.
She found an improvement of 7.6% in mean power during a 40 km time trial and 3.5% in peak power.
Implications for rowing? Those low stroke rate pieces may still have a place in your competitive season. Of course they have added benefits for rowers as they allow continued development of precise technique.
Of course the study was for cyclists competing over a longer distance, but the potential implications are interesting.